Publications by year
In Press
Cockcroft EJ, williams C, jackman S, armstrong N, barker A (In Press). Agreement and Reliability of Fasted and Oral Glucose Tolerance Test-Derived Indices of Insulin Sensitivity and Beta Cell Function in Boys. International journal of sports medicince
Bowtell J, Shore A, Jackman S (In Press). An appraisal of trials investigating the effects on macular pigment optical density of lutein and zeaxanthin dietary interventions: a narrative review. Nutrition Reviews
Jackman SR, Witard OC, Philp A, Wallis GA, Baar K, Tipton KD (In Press). Branched-Chain Amino Acid Ingestion Stimulates Muscle Myofibrillar Protein Synthesis following Resistance Exercise in Humans. Frontiers in Physiology
Piacentini, MF, Witard, OC, Jackman SR, Tonoli, C, Turner, JE, Kies, AK, Jeukendrup, AE, Tipton, KD, Meeusen, R (In Press). Intensive Training Affects Mood with no Effect on Brain-Derived Neurotrophic Factor.
2023
Jackman SR, Wallis GA, Yu J, Philp A, Baar K, Tipton KD, Witard OC (2023). Co-ingestion of branched-chain amino acids and carbohydrate stimulates myofibrillar protein synthesis following resistance exercise in trained young men.
International Journal of Sport Nutrition and Exercise Metabolism,
33Abstract:
Co-ingestion of branched-chain amino acids and carbohydrate stimulates myofibrillar protein synthesis following resistance exercise in trained young men
Branched-chain amino acids (BCAA) and carbohydrate (CHO) are commonly recommended postexercise supplements. However,
no study has examined the interaction of CHO and BCAA ingestion on myofibrillar protein synthesis (MyoPS) rates following
exercise. We aimed to determine the response of MyoPS to the co-ingestion of BCAA and CHO following an acute bout of
resistance exercise. Ten resistance-trained young men completed two trials in counterbalanced order, ingesting isocaloric drinks
containing either 30.6-g CHO plus 5.6-g BCAA (B + C) or 34.7-g CHO alone following a bout of unilateral, leg resistance exercise.
MyoPS was measured postexercise with a primed, constant infusion of L-[ring13
C6] phenylalanine and collection of muscle
biopsies pre- and 4 hr postdrink ingestion. Blood samples were collected at time points before and after drink ingestion. Serum
insulin concentrations increased to a similar extent in both trials (p >. 05), peaking at 30 min postdrink ingestion. Plasma leucine
(514 ± 34 nmol/L), isoleucine (282 ± 23 nmol/L), and valine (687 ± 33 nmol/L) concentrations peaked at 0.5 hr postdrink in B + C
and remained elevated for 3 hr during exercise recovery. MyoPS was ∼15% greater (95% confidence interval [−0.002, 0.028],
p =. 039, Cohen’s d = 0.63) in B + C (0.128%/hr ± 0.011%/hr) than CHO alone (0.115%/hr ± 0.011%/hr) over the 4 hr postexercise
period. Co-ingestion of BCAA and CHO augments the acute response of MyoPS to resistance exercise in trained young males.
Abstract.
O'Leary M, Jackman SR, Bowtell JL (2023). Shatavari Supplementation in Postmenopausal Women Alters the Skeletal Muscle Proteome and Upregulates Proteins and Pathways Involved in Training Adaptation.
2022
Wangdi JT, O'Leary MF, Kelly VG, Jackman SR, Tang JCY, Dutton J, Bowtell JL (2022). Tart Cherry Supplement Enhances Skeletal Muscle Glutathione Peroxidase Expression and Functional Recovery after Muscle Damage.
Med Sci Sports Exerc,
54(4), 609-621.
Abstract:
Tart Cherry Supplement Enhances Skeletal Muscle Glutathione Peroxidase Expression and Functional Recovery after Muscle Damage.
INTRODUCTION: Montmorency cherry concentrate (MCC) supplementation enhances functional recovery from exercise, potentially due to antioxidant and anti-inflammatory effects. However, to date, supporting empirical evidence for these mechanistic hypotheses is reliant on indirect blood biomarkers. This study is the first to investigate functional recovery from exercise alongside molecular changes within the exercised muscle after MCC supplementation. METHODS: Ten participants completed two maximal unilateral eccentric knee extension trials after MCC or placebo (PLA) supplementation for 7 d before and 48 h after exercise. Knee extension maximum voluntary contractions, maximal isokinetic contractions, single leg jumps, and soreness measures were assessed before, immediately, 24 h, and 48 h after exercise. Venous blood and vastus lateralis muscle samples were collected at each time point. Plasma concentrations of interleukin-6, tumor necrosis factor alpha, C-reactive protein, creatine kinase, and phenolic acids were quantified. Intramuscular mRNA expressions of superoxide dismutase 1 (SOD1), SOD3, glutathione peroxidase 1 (GPX1), GPX3, GPX4, GPX7, catalase, and nuclear factor erythroid 2-related factor 2 and relative intramuscular protein expressions of SOD1, catalase, and GPX3 were quantified. RESULTS: MCC supplementation enhanced the recovery of normalized maximum voluntary contraction 1-s average compared with PLA (postexercise PLA, 59.5% ± 18.0%, vs MCC, 76.5% ± 13.9%; 24 h PLA, 69.8% ± 15.9%, vs MCC, 80.5% ± 15.3%; supplementation effect P = 0.024). MCC supplementation increased plasma hydroxybenzoic, hippuric, and vanillic acid concentrations (supplementation effect P = 0.028, P = 0.002, P = 0.003); SOD3, GPX3, GPX4, GPX7 (supplement effect P < 0.05), and GPX1 (interaction effect P = 0.017) gene expression; and GPX3 protein expression (supplementation effect P = 0.004) versus PLA. There were no significant differences between conditions for other outcome measures. CONCLUSIONS: MCC supplementation conserved isometric muscle strength and upregulated antioxidant gene and protein expression in parallel with increased phenolic acid concentrations.
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Author URL.
2021
Kilroe SP, Fulford J, Jackman S, Holwerda A, Gijsen A, van Loon L, Wall BT (2021). Dietary protein intake does not modulate daily myofibrillar protein synthesis rates or loss of muscle mass and function during short-term immobilization in young men: a randomized controlled trial.
Am J Clin Nutr,
113(3), 548-561.
Abstract:
Dietary protein intake does not modulate daily myofibrillar protein synthesis rates or loss of muscle mass and function during short-term immobilization in young men: a randomized controlled trial.
BACKGROUND: Short-term ( 0.05). Immobilization led to 2.3 ± 0.4%, 2.7 ± 0.2%, and 2.0 ± 0.4% decreases in quadriceps muscle volume (P 0.05). Daily MyoPS rates during immobilization were 30 ± 2% (HIGH), 26 ± 3% (LOW), and 27 ± 2% (NO) lower in the immobilized compared with the control leg, with no significant differences between groups (P > 0.05). CONCLUSIONS: Three days of muscle disuse induces considerable declines in muscle mass and daily MyoPS rates. However, daily protein intake does not modulate any of these muscle deconditioning responses.Clinical trial registry number: NCT03797781.
Abstract.
Author URL.
O’Leary MF, Jackman SR, Sabou VR, Campbell MI, Tang JCY, Dutton J, Bowtell JL (2021). Shatavari Supplementation in Postmenopausal Women Improves Handgrip Strength and Increases Vastus Lateralis Myosin Regulatory Light Chain Phosphorylation But Does Not Alter Markers of Bone Turnover: a Randomised Controlled Trial.
O’Leary MF, Jackman SR, Sabou VR, Campbell MI, Tang JCY, Dutton J, Bowtell JL (2021). Shatavari Supplementation in Postmenopausal Women Improves Handgrip Strength and Increases Vastus lateralis Myosin Regulatory Light Chain Phosphorylation but Does Not Alter Markers of Bone Turnover.
Nutrients,
13(12), 4282-4282.
Abstract:
Shatavari Supplementation in Postmenopausal Women Improves Handgrip Strength and Increases Vastus lateralis Myosin Regulatory Light Chain Phosphorylation but Does Not Alter Markers of Bone Turnover
Shatavari has long been used as an Ayurvedic herb for women’s health, but empirical evidence for its effectiveness has been lacking. Shatavari contains phytoestrogenic compounds that bind to the estradiol receptor. Postmenopausal estradiol deficiency contributes to sarcopenia and osteoporosis. In a randomised double-blind trial, 20 postmenopausal women (68.5 ± 6 years) ingested either placebo (N = 10) or shatavari (N = 10; 1000 mg/d, equivalent to 26,500 mg/d fresh weight shatavari) for 6 weeks. Handgrip and knee extensor strength were measured at baseline and at 6 weeks. Vastus lateralis (VL) biopsy samples were obtained. Data are presented as difference scores (Week 6—baseline, median ± interquartile range). Handgrip (but not knee extensor) strength was improved by shatavari supplementation (shatavari +0.7 ± 1.1 kg, placebo −0.4 ± 1.3 kg; p = 0.04). Myosin regulatory light chain phosphorylation, a known marker of improved myosin contractile function, was increased in VL following shatavari supplementation (immunoblotting; placebo −0.08 ± 0.5 a.u. shatavari +0.3 ± 1 arbitrary units (a.u.); p = 0.03). Shatavari increased the phosphorylation of Aktser473 (Aktser473 (placebo −0.6 ± 0.6 a.u. shatavari +0.2 ± 1.3 a.u.; p = 0.03) in VL. Shatavari supplementation did not alter plasma markers of bone turnover (P1NP, β-CTX) and stimulation of human osteoblasts with pooled sera (N = 8 per condition) from placebo and shatavari supplementation conditions did not alter cytokine or metabolic markers of osteoblast activity. Shatavari may improve muscle function and contractility via myosin conformational change and further investigation of its utility in conserving and enhancing musculoskeletal function, in larger and more diverse cohorts, is warranted.
Abstract.
Jones H (2021). The effect of patterns and distributions of physical activity on blood glucose control in individuals with Type 2 Diabetes Mellitus: an exploratory study.
Abstract:
The effect of patterns and distributions of physical activity on blood glucose control in individuals with Type 2 Diabetes Mellitus: an exploratory study
Physical activity (PA) is known to be beneficial for blood glucose control in individuals with Type 2 Diabetes Mellitus (T2DM). The American Diabetes Association (ADA) recommends 150 minutes or more of moderate to vigorous physical activity (MVPA) per week for individuals with T2DM, which may be perceived as an intimidating target. Recent evidence suggests that firstly, PA of all intensities, including lighter intensity activity, may be beneficial for blood glucose control and that secondly, the pattern in which PA is accumulated may be important, however this is poorly understood. The purpose of this thesis was to provide a detailed understanding of how the patterns (extent to which bouts of activity durations and intensities are accumulated within and between days) and distributions of all habitual PA (not just moderate and vigorous) influence daily glucose fluctations in individuals with T2DM. Free living PA was measured using an ActivPal accelerometer worn on the thigh and 24 hour glucose was measured using an iPro continuous glucose monitor in 33 participants (age, 72 ± 11 years). Stepping at a light-intensity and overall stepping time were associated with increased glucose time in target glucose range (TIR) and total daily area under the curve (AUC). Stepping at or above moderate intensity was associated with lower mean amplitude of glucose excursions (MAGE) (95% CI -0.016(-0.032, -0.001), p = 0.04). Individuals with high variation and high volumes of stepping time at or above moderate intensity and total daily steps were found to have significantly greater glucose TIR when compared to individuals with low variation and low volumes of activity. These findings suggest that daily light intensity activity is beneficial for daily glucose, and investigating activity on a daily basis rather than averaged over a week is crucial for improving the understanding of associations between glucose and activity in free-living.
Abstract.
2020
Torquati L, Jackman SR, Bowtell JL (2020). Can Inulin-Enriched Cereal Products Improve Mucosal Immunity in Athletes?. Clinical Nutrition ESPEN, 40, 500-501.
Monteyne AJ, Coelho MOC, Porter C, Abdelrahman DR, Jameson TSO, Jackman SR, Blackwell JR, Finnigan TJA, Stephens FB, Dirks ML, et al (2020). Mycoprotein ingestion stimulates protein synthesis rates to a greater extent than milk protein in rested and exercised skeletal muscle of healthy young men: a randomized controlled trial.
Am J Clin Nutr,
112(2), 318-333.
Abstract:
Mycoprotein ingestion stimulates protein synthesis rates to a greater extent than milk protein in rested and exercised skeletal muscle of healthy young men: a randomized controlled trial.
BACKGROUND: Mycoprotein is a fungal-derived sustainable protein-rich food source, and its ingestion results in systemic amino acid and leucine concentrations similar to that following milk protein ingestion. OBJECTIVE: We assessed the mixed skeletal muscle protein synthetic response to the ingestion of a single bolus of mycoprotein compared with a leucine-matched bolus of milk protein, in rested and exercised muscle of resistance-trained young men. METHODS: Twenty resistance-trained healthy young males (age: 22 ± 1 y, body mass: 82 ± 2 kg, BMI: 25 ± 1 kg·m-2) took part in a randomized, double-blind, parallel-group study. Participants received primed, continuous infusions of L-[ring-2H5]phenylalanine and ingested either 31 g (26.2 g protein: 2.5 g leucine) milk protein (MILK) or 70 g (31.5 g protein: 2.5 g leucine) mycoprotein (MYCO) following a bout of unilateral resistance-type exercise (contralateral leg acting as resting control). Blood and m. vastus lateralis muscle samples were collected before exercise and protein ingestion, and following a 4-h postprandial period to assess mixed muscle fractional protein synthetic rates (FSRs) and myocellular signaling in response to the protein beverages in resting and exercised muscle. RESULTS: Mixed muscle FSRs increased following MILK ingestion (from 0.036 ± 0.008 to 0.052 ± 0.006%·h-1 in rested, and 0.035 ± 0.008 to 0.056 ± 0.005%·h-1 in exercised muscle; P
Abstract.
Author URL.
Kilroe SP, Fulford J, Holwerda AM, Jackman SR, Lee BP, Gijsen AP, van Loon LJC, Wall BT (2020). Short-term muscle disuse induces a rapid and sustained decline in daily myofibrillar protein synthesis rates.
American Journal of Physiology-Endocrinology and Metabolism,
318(2), E117-E130.
Abstract:
Short-term muscle disuse induces a rapid and sustained decline in daily myofibrillar protein synthesis rates
Short-term muscle disuse has been reported to lower both postabsorptive and postprandial myofibrillar protein synthesis rates. This study assessed the impact of disuse on daily myofibrillar protein synthesis rates following short-term (2 and 7 days) muscle disuse under free living conditions. Thirteen healthy young men (age: 20 ± 1 yr; BMI: 23 ± 1 kg/m−2) underwent 7 days of unilateral leg immobilization via a knee brace, with the nonimmobilized leg acting as a control. Four days before immobilization participants ingested 400 mL of 70% deuterated water, with 50-mL doses consumed daily thereafter. Upper leg bilateral MRI scans and muscle biopsies were collected before and after 2 and 7 days of immobilization to determine quadriceps volume and daily myofibrillar protein synthesis rates. Immobilization reduced quadriceps volume in the immobilized leg by 1.7 ± 0.3 and 6.7 ± 0.6% after 2 and 7 days, respectively, with no changes in the control leg. Over the 1-wk immobilization period, myofibrillar protein synthesis rates were 36 ± 4% lower in the immobilized (0.81 ± 0.04%/day) compared with the control (1.26 ± 0.04%/day) leg ( P < 0.001). Myofibrillar protein synthesis rates in the control leg did not change over time ( P = 0.775), but in the immobilized leg they were numerically lower during the 0- to 2-day period (16 ± 6%, 1.11 ± 0.09%/day, P = 0.153) and were significantly lower during the 2- to 7-day period (44 ± 5%, 0.70 ± 0.06%/day, P < 0.001) when compared with the control leg. We conclude that 1 wk of muscle disuse induces a rapid and sustained decline in daily myofibrillar protein synthesis rates in healthy young men.
Abstract.
2019
Aboo Bakkar Z, Fulford J, Gates PE, Jackman SR, Jones AM, Bond B, Bowtell JL (2019). Montmorency cherry supplementation attenuates vascular dysfunction induced by prolonged forearm occlusion in overweight, middle-aged men.
J Appl Physiol (1985),
126(1), 246-254.
Abstract:
Montmorency cherry supplementation attenuates vascular dysfunction induced by prolonged forearm occlusion in overweight, middle-aged men.
Flavonoid supplementation improves brachial artery flow-mediated dilation (FMD), but it is not known whether flavonoids protect against vascular dysfunction induced by ischemia-reperfusion (IR) injury and associated respiratory burst. In a randomized, double-blind, placebo-controlled, crossover study, we investigated whether 4 wk supplementation with freeze-dried Montmorency cherry (MC) attenuated suppression of FMD after IR induced by prolonged forearm occlusion. Twelve physically inactive overweight, middle-aged men (52.8 ± 5.8 yr, BMI: 28.1 ± 5.3 kg/m2) consumed MC (235 mg/day anthocyanins) or placebo capsules for 4 wk, with supplementation blocks separated by 4 wk washout. Before and after each supplementation block, FMD responses and plasma nitrate and nitrite ([ NO2- ]) concentrations were measured at baseline and 15, 30, and 45 min after prolonged (20 min) forearm occlusion. FMD response was significantly depressed by the prolonged occlusion ( P < 0.001). After a 45-min reperfusion, FMD was restored to baseline levels after MC (ΔFMD presupplementation: -30.5 ± 8.4%, postsupplementation: -0.6 ± 9.5%) but not placebo supplementation (ΔFMD presupplementation: -11.6 ± 10.6, postsupplementation: -25.4 ± 4.0%; condition × supplement interaction: P = 0.038). Plasma [ NO2- ] decreased after prolonged occlusion but recovered faster after MC compared with placebo (Δ45 min to baseline; MC: presupplementation: -15.3 ± 9.6, postsupplementation: -6.2 ± 8.1; Placebo: presupplementation: -16.3 ± 5.9, postsupplementation: -27.7 ± 11.1 nmol/l; condition × supplement × time interaction: P = 0.033). Plasma peroxiredoxin concentration ([Prx2]) was significantly higher after MC (presupplementation: 22.8 ± 1.4, postsupplementation: 28.0 ± 2.4 ng/ml, P = 0.029) but not after placebo supplementation (presupplementation: 22.1 ± 2.2, postsupplementation: 23.7 ± 1.5 ng/ml). In conclusion, 4 wk MC supplementation enhanced recovery of endothelium-dependent vasodilatation after IR, in parallel with faster recovery of plasma [ NO2- ], suggesting NO dependency. These protective effects seem to be related to increased plasma [Prx2], presumably conferring protection against the respiratory burst during reperfusion. NEW & NOTEWORTHY This is the first study to demonstrate that 4 wk of Montmorency cherry powder supplementation exerted protective effects on endothelium-dependent vasodilation after transient ischemia-reperfusion injury in overweight, physically inactive, nonmedicated, hypertensive middle-aged men. These effects seem to be due to increased nitric oxide availability, as evidenced by higher plasma nitrite concentration and peak arterial diameter during the flow-mediated dilation measurement. This may be a consequence of increased concentration of peroxiredoxin and other antioxidant systems and, hence, reduced reactive oxygen species exposure.
Abstract.
Author URL.
KILROE SP, FULFORD J, JACKMAN SR, VAN LOON LJC, WALL BT (2019). Temporal Muscle-specific Disuse Atrophy during One Week of Leg Immobilization.
Medicine & Science in Sports & Exercise,
52(4), 944-954.
Abstract:
Temporal Muscle-specific Disuse Atrophy during One Week of Leg Immobilization
ABSTRACT
.
. Purpose
. Musculoskeletal injuries necessitate periods of disuse (i.e. limb immobilization) during which rapid skeletal muscle atrophy occurs. The relative susceptibility of different muscles of the thigh to disuse atrophy remains uninvestigated. We assessed muscle disuse atrophy of individual thigh muscles throughout 1 wk of unilateral knee immobilization.
.
.
. Methods
. Thirteen healthy, young (20.2 ± 0.6 yr) men underwent 7 d of unilateral leg immobilization via knee bracing. Magnetic resonance imaging scans were performed bilaterally prior to, and following 2 and 7 d of immobilization to determine the volume and anatomical cross-sectional area of the individual muscle groups of the upper legs.
.
.
. Results
. In contrast to the control leg, total thigh muscle volume had decreased by 1.7% ± 0.3% (P < 0.01) and 5.5% ± 0.6% (P < 0.001) in the immobilized leg after 2 and 7 d of disuse, respectively. Muscle loss was significantly greater in the Musculus quadriceps (day 2; 1.7% ± 0.3% (P < 0.05) and day 7; 6.7% ± 0.6%) when compared with the Musculus hamstrings (day 2; 1.4% ± 0.2% (P < 0.01) and day 7; 3.5% ± 0.3%) after 7 d of disuse (P < 0.001). Individual muscles of the thigh exhibited different atrophy rates with the Musculus vastus lateralis anatomical cross-sectional area showing the greater (2.6% ± 0.4% and 7.2% ± 0.8%), and the Musculus gracilis the lesser (1.1% ± 0.7% and 2.3% ± 1.0%) decline following 2 and 7 d of immobilization, respectively (P < 0.01).
.
.
. Conclusions
. Thigh muscle disuse atrophy occurs rapidly and is already evident within 2 d of leg immobilization and progresses at a similar rate over the next 5 d (~0.8% muscle loss per day). M. quadriceps muscle shows more atrophy when compared with the M. hamstrings.
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Abstract.
Cockcroft EJ, Bond B, Williams CA, Harris S, Jackman SR, Armstrong N, Barker AR (2019). The effects of two weeks high-intensity interval training on fasting glucose, glucose tolerance and insulin resistance in adolescent boys: a pilot study.
BMC Sports Science, Medicine and Rehabilitation,
11(1).
Abstract:
The effects of two weeks high-intensity interval training on fasting glucose, glucose tolerance and insulin resistance in adolescent boys: a pilot study
Abstract
. Background
. Current evidence of metabolic health benefits of high-intensity interval training (HIIT) are limited to longer training periods or conducted in overweight youth. This study assessed 1) fasting and postprandial insulin and glucose before and after 2 weeks of HIIT in healthy adolescent boys, and 2) the relationship between pre intervention health outcomes and the effects of the HIIT intervention.
.
. Methods
. Seven healthy boys (age:14.3 ± 0.3 y, BMI: 21.6 ± 2.6, 3 participants classified as overweight) completed 6 sessions of HIIT over 2 weeks. Insulin resistance (IR) and blood glucose and insulin responses to a Mixed Meal Tolerance Test (MMTT) were assessed before (PRE), 20 h and 70 h after (POST) the final HIIT session.
.
. Results
. Two weeks of HIIT had no effect on fasting plasma glucose, insulin or IR at 20 h and 70 h POST HIIT, nor insulin and glucose response to MMTT (all P > 0.05). There was a strong negative correlation between PRE training IR and change in IR after HIIT (r = − 0.96, P < 0.05).
.
. Conclusion
. Two weeks of HIIT did not elicit improvements to fasting or postprandial glucose or insulin health outcomes in a group of adolescent boys. However the negative correlation between PRE IR and improvements after HIIT suggest that interventions of this type may be effective in adolescents with raised baseline IR.
.
Abstract.
Cockcroft E, Bond B, Williams CA, Harris S, Jackman SR, Armstrong N, Barker AR (2019). The effects of two weeks high-intensity interval training on fasting glucose, glucose tolerance and insulin resistance in adolescent boys; a pilot study.
2018
Cockcroft EJ, Williams CA, Jackman SR, Bassi S, Armstrong N, Barker AR (2018). A single bout of high-intensity interval exercise and work-matched moderate-intensity exercise has minimal effect on glucose tolerance and insulin sensitivity in 7- to 10-year-old boys.
Journal of Sports Sciences,
36(2), 149-155.
Abstract:
A single bout of high-intensity interval exercise and work-matched moderate-intensity exercise has minimal effect on glucose tolerance and insulin sensitivity in 7- to 10-year-old boys
The purpose of this study was to assess the acute effect of high-intensity interval exercise (HIIE) and moderate-intensity exercise (MIE) on glucose tolerance, insulin sensitivity and fat oxidation in young boys. Eleven boys (8.8 ± 0.8 y) completed three conditions: 1) HIIE; 2) work-matched MIE; and 3) rest (CON) followed by an oral glucose tolerance test (OGTT) to determine glucose tolerance and insulin sensitivity (Cederholm index). Fat oxidation was measured following the OGTT using indirect calorimetry. There was no effect for condition on plasma [glucose] and [insulin] area under the curve (AUC) responses following the OGTT (P > 0.09). However, there was a “trend” for a condition effect for insulin sensitivity with a small increase after HIIE (P = 0.04, ES = 0.28, 9.7%) and MIE (P = 0.07, ES = 0.21, 6.5%) compared to CON. There was an increase in fat oxidation AUC following HIIE (P = 0.008, ES = 0.79, 38.9%) compared to CON, but with no differences between MIE and CON and HIIE and MIE (P > 0.13). In conclusion, 7- to 10-year-old boys may have limited scope to improve insulin sensitivity and glucose tolerance after a single bout of HIIE and MIE. However, fat oxidation is augmented after HIIE but not MIE.
Abstract.
Dirks ML, Stephens FB, Jackman SR, Gordo J, Machin D, Pulsford R, van Loon L, Wall B (2018). A single day of bed rest, irrespective of energy balance, does not affect skeletal muscle gene expression or insulin sensitivity. Experimental Physiology, 103(6), 860-875.
Morgan PT, Wollman PM, Jackman SR, Bowtell JL (2018). Flavanol-Rich Cacao Mucilage Juice Enhances Recovery of Power but Not Strength from Intensive Exercise in Healthy, Young Men.
Sports (Basel),
6(4).
Abstract:
Flavanol-Rich Cacao Mucilage Juice Enhances Recovery of Power but Not Strength from Intensive Exercise in Healthy, Young Men.
(1) Background: Mucilage within cacao pods contains high levels of polyphenols. We investigated whether consumption of cacao juice enhances the recovery of muscle function following intensive knee extension exercise. (2) Methods: Ten recreationally active males completed two trials of 10 sets of 10 single leg knee extensions at ~80% one repetition maximum. Participants consumed each supplement (ZumoCacao® juice, CJ or a dextrose drink, PL) for 7 days prior to and 48 h post exercise. Knee extension maximum voluntary contraction (MVC) and a counter movement jump (CMJ) were performed at baseline, immediately, 24 h, and 48 h post-exercise. Venous blood samples were collected at each time point and analyzed for indices of inflammation, oxidative damage, and muscle damage. (3) Results: CMJ height recovered faster with CJ at 24 h and 48 h post-exercise (p < 0.05), but there was no effect of CJ on recovery of MVC (both p > 0.05). There was also no effect of the trial on any blood markers (all p > 0.05). (4) Conclusions: Supplementation with CJ for 7 days prior to and 2 days after intensive knee extensor exercise improved functional recovery as shown by an improved recovery of CMJ up to 48 h post-exercise. However, the precise mechanism of action is unclear and requires further investigation.
Abstract.
Author URL.
Bowtell J, Mohr M, Fulford J, Jackman S, Ermidis G, Krustrup P, Mileva K (2018). Improved Exercise Tolerance with Caffeine is Associated with Modulation of both Peripheral and Central Neural Processes in Human Participants. Frontiers in Nutrition, 5
Aboo Bakkar Z, Fulford J, Gates PE, Jackman SR, Jones AM, Bond B, Bowtell JL (2018). Prolonged forearm ischemia attenuates endothelium-dependent vasodilatation and plasma nitric oxide metabolites in overweight middle-aged men.
European Journal of Applied Physiology,
118(8), 1565-1572.
Abstract:
Prolonged forearm ischemia attenuates endothelium-dependent vasodilatation and plasma nitric oxide metabolites in overweight middle-aged men
Purpose: Repeated cycles of endothelial ischemia–reperfusion injury and the resulting respiratory burst contribute to the irreversible pathophysiology of vascular diseases, and yet, the effects of ischemia reperfusion on vascular function, oxidative stress, and nitric oxide (NO) bioavailability have not been assessed simultaneously. Therefore, this study sought to examine the effects of prolonged forearm occlusion and subsequent reperfusion on NO-dependent brachial artery endothelial function. Methods: Flow-mediated dilatation was measured at baseline and 15, 30, and 45 min after 20-min forearm occlusion in 14 healthy, but physically inactive middle-aged men (53.7 ± 1.2 years, BMI: 28.1 ± 0.1 kg m−2). Venous blood samples collected from the occluded arm were analyzed for NO metabolites and markers of oxidative stress. Results: FMD was significantly depressed after the prolonged occlusion compared to baseline, with a significant reduction 15-min post-occlusion (6.6 ± 0.7 to 2.9 ± 0.4%, p < 0.001); FMD remained depressed after 30 min (4.1 ± 0.6%, p = 0.001), but was not significantly different to baseline after 45-min recovery (5.4 ± 0.7%, p = 0.079). Plasma nitrate (main time effect: p = 0.015) and nitrite (main time effect: p = 0.034) concentrations were significantly reduced after prolonged occlusion. Plasma catalase activity was significantly elevated at 4- (p = 0.016) and 45-min (p = 0.001) post-occlusion, but plasma peroxiredoxin 2 and protein carbonyl content did not change. Conclusions: Prolonged forearm occlusion resulted in acute impairment of endothelium-dependent vasodilatation of the brachial artery for at least 30 min after reperfusion. We demonstrate that this vascular dysfunction is associated with oxidative stress and reduced NO bioavailability following reperfusion.
Abstract.
Jackman SR, Brook MS, Pulsford RM, Cockcroft EJ, Campbell MI, Rankin D, Atherton P, Smith K, Bowtell JL (2018). Tart cherry concentrate does not enhance muscle protein synthesis response to exercise and protein in healthy older men.
Exp Gerontol,
110, 202-208.
Abstract:
Tart cherry concentrate does not enhance muscle protein synthesis response to exercise and protein in healthy older men.
BACKGROUND: Oxidative stress and inflammation may contribute to anabolic resistance in response to protein and exercise in older adults. We investigated whether consumption of montmorency cherry concentrate (MCC) increased anabolic sensitivity to protein ingestion and resistance exercise in healthy older men. METHODS: Sixteen healthy older men were randomized to receive MCC (60 mL·d-1) or placebo (PLA) for two weeks, after baseline measures in week 1. During week 3, participants consumed 10 g whey protein·d-1 and completed three bouts of unilateral leg resistance exercise (4 × 8-10 repetitions at 80% 1RM). Participants consumed a bolus (150 mL) and weekly (50 mL) doses of deuterated water. Body water 2H enrichment was measured in saliva and vastus lateralis biopsies were taken from the non-exercised leg after weeks 1, 2 and 3, and the exercised leg after week 3, to measure tracer incorporation at rest, in response to protein and protein + exercise. RESULTS: Myofibrillar protein synthesis increased in response to exercise + protein compared to rest (p
Abstract.
Author URL.
2017
Cockcroft EJ, Williams CA, Weaver H, O'Connor A, Jackman SR, Armstrong N, Barker AR (2017). Acute Exercise and Insulin Sensitivity in Boys: a Time-Course Study.
Int J Sports Med,
38(13), 967-974.
Abstract:
Acute Exercise and Insulin Sensitivity in Boys: a Time-Course Study.
This study examined the time course of adaptions in insulin sensitivity (IS) in adolescent boys after acute high-intensity interval exercise (HIIE) and moderate-intensity exercise (MIE). Eight boys (15.1±0.4 y) completed three 3-day experimental trials in a randomised order: 1) 8×1 min cycling at 90% peak power with 75 s recovery (HIIE); 2) cycling at 90% of gas exchange threshold for a duration to match work during HIIE (MIE); and 3) rest (CON). Plasma [glucose] and [insulin] were measured before (PRE-Ex), 24 and 48 h post (24 h-POST, 48 h-POST) in a fasted state, and 40 min (POST-Ex) and 24 h (24 h-POST) post in response to an oral glucose tolerance test (OGTT). IS was estimated using the Cederholm (OGTT) and HOMA (fasted) indices. There was no change to HOMA at 24 h or 48 h-POST (all P>0.05). IS from the OGTT was higher POST-EX for HIIE compared to CON (17.4%, P=0.010, ES=1.06), and a non-significant increase in IS after MIE compared to CON (9.0%, P=0.14, ES=0.59). At 24 h-POST, IS was higher following both HIIE and MIE compared to CON (HIIE: P=0.019, 13.2%, ES=0.88; MIE: 9.7%, P=0.024, ES=0.65). In conclusion, improvements to IS after a single bout of HIIE and MIE persist up to 24 h after exercise when assessed by OGTT.
Abstract.
Author URL.
2016
Piacentini MF, Witard OC, Tonoli C, Jackman SR, Turner JE, Kies AK, Jeukendrup AE, Tipton KD, Meeusen R (2016). Effect of Intensive Training on Mood with No Effect on Brain-Derived Neurotrophic Factor.
International Journal of Sports Physiology and Performance,
11(6), 824-830.
Abstract:
Effect of Intensive Training on Mood with No Effect on Brain-Derived Neurotrophic Factor
Context:Monitoring mood state is a useful tool for avoiding nonfunctional overreaching. Brain-derived neurotrophic factor (BDNF) is implicated in stress-related mood disorders.Purpose:To investigate the impact of intensified training-induced mood disturbance on plasma BDNF concentrations at rest and in response to exercise.Methods: Eight cyclists performed 1 wk of normal (NT), 1 wk of intensified (INT), and 1 wk of recovery (REC) training. Fasted blood samples were collected before and after exercise on day 7 of each training week and analyzed for plasma BDNF and cortisol concentrations. A 24-item Profile of Mood State questionnaire was administered on day 7 of each training week, and global mood score (GMS) was calculated.Results:Time-trial performance was impaired during INT (P =. 01) and REC (P =. 02) compared with NT. Basal plasma cortisol (NT = 153 ± 16 ng/mL, INT = 130 ± 11 ng/mL, REC = 150 ± 14 ng/ml) and BDNF (NT = 484 ± 122 pg/mL, INT = 488 ± 122 pg/mL, REC = 383 ± 56 pg/mL) concentrations were similar between training conditions. Likewise, similar exercise-induced increases in cortisol and BDNF concentrations were observed between training conditions. GMS was 32% greater during INT vs NT (P <. 001).Conclusions: Consistent with a state of functional overreaching (FOR), impairments in performance and mood state with INT were restored after 1 wk of REC. These results support evidence for mood changes before plasma BDNF concentrations as a biochemical marker of FOR and that cortisol is not a useful marker for predicting FOR.
Abstract.
Macnaughton LS, Jeromson S, Witard OC, Jackman SR, Hamilton DL, Tipton KD (2016). Resistance Exercise Sustains p70S6K1 Activity in Response to Protein Ingestion at 4 hours: 2923 June 3 1: 30 PM - 1: 45 PM.
Med Sci Sports Exerc,
48(5 Suppl 1).
Author URL.
Bowtell JL, Jackman SR, Scott S, Connolly LJ, Mohr M, Ermidis G, Julian R, Yousefian F, Helge EW, Jørgensen NR, et al (2016). Short duration small sided football and to a lesser extent whole body vibration exercise induce acute changes in markers of bone turnover.
BioMed Research International,
2016Abstract:
Short duration small sided football and to a lesser extent whole body vibration exercise induce acute changes in markers of bone turnover
We aimed to study whether short-duration vibration exercise or football sessions of two different durations acutely changed plasma markers of bone turnover and muscle strain. Inactive premenopausal women (n=56) were randomized to complete a single bout of short (FG15) or long duration (FG60) small sided football or low magnitude whole body vibration training (VIB). Procollagen type 1 amino-terminal propeptide (P1NP) was increased during exercise for FG15 (51.6±23.0 to 56.5±22.5 μg·L-1, mean ± SD, P
Abstract.
2015
Bond B, Williams CA, Jackman SR, Woodward A, Armstrong N, Barker AR (2015). Accumulating exercise and postprandial health in adolescents.
Metabolism: clinical and experimentalAbstract:
Accumulating exercise and postprandial health in adolescents
Purpose: to examine the influence of exercise intensity on postprandial health outcomes in adolescents when exercise is accumulated throughout the day. Methods: 19 adolescents (9 male, 13.7 ± 0.4 y) completed three 1-day trials in a randomised order: 1) rest (CON); or four bouts of 2) 2 x 1 min cycling at 90% peak power with 75 s recovery (high-intensity interval exercise; HIIE); or 3) cycling at 90% of the gas exchange threshold (moderate-intensity exercise; MIE), which was work-matched to HIIE. Each bout was separated by 2 hours. Participants consumed a high fat milkshake for breakfast and lunch. Postprandial triacylglycerol (TAG), glucose, systolic blood pressure (SBP) and fat oxidation were assessed throughout the day. Results: There was no effect of trial on total area under the curve (TAUC) for TAG (P=0.87). TAUC-glucose was lower in HIIE compared to CON (P=0.03, ES=0.42) and MIE (P=0.04, ES=0.41), with no difference between MIE and CON (P=0.89, ES=0.04). Postprandial SBP was lower in HIIE compared to CON (P=0.04, ES=0.50) and MIE (P=0.04, ES=0.40), but not different between MIE and CON (P=0.52, ES=0.11). Resting fat oxidation was increased in HIIE compared to CON (P=0.01, ES=0.74) and MIE (P=0.05, ES=0.51), with no difference between MIE and CON (P=0.37, ES=0.24). Conclusion: Neither exercise trial attenuated postprandial lipaemia. However, accumulating brief bouts of HIIE, but not MIE, reduced postprandial plasma glucose and SBP, and increased resting fat oxidation in adolescent boys and girls. The intensity of accumulated exercise may therefore have important implications for health outcomes in youth.
Abstract.
Heneghan NR, Adab P, Jackman S, Balanos GM (2015). Authors’ reply to letter to the editor by engel and vemulpad. International Journal of Therapy and Rehabilitation, 22(6).
Bond B, Williams CA, Isic C, Jackman SR, Tolfrey K, Barrett LA, Barker AR (2015). Exercise intensity and postprandial health outcomes in adolescents.
Eur J Appl Physiol,
115(5), 927-936.
Abstract:
Exercise intensity and postprandial health outcomes in adolescents.
PURPOSE: the effect of exercise intensity and sex on postprandial risk factors for cardiovascular disease in adolescents is unknown. We examined the effect of a single bout of work-matched high-intensity interval exercise (HIIE) and moderate-intensity exercise (MIE) on postprandial triacylglycerol (TAG) and systolic blood pressure (SBP) in adolescents. METHOD: Twenty adolescents (10 male, 14.3 ± 0.3 years) completed three 1-day trials: (1) rest (CON); (2) 8 × 1 min cycling at 90 % peak power with 75 s recovery (HIIE); (3) cycling at 90 % of the gas exchange threshold (MIE), 1 h before consuming a high-fat milkshake (1.50 g fat and 80 kJ kg(-1)). Postprandial TAG, SBP and fat oxidation were assessed over 4 h RESULTS: Compared to CON, the incremental area under the curve for TAG (IAUC-TAG) was not significantly lowered in HIIE [P = 0.22, effect size (ES) = 0.24] or MIE (P = 0.65, ES = 0.04) for boys. For girls, HIIE and MIE lowered IAUC-TAG by 34 % (P = 0.02, ES = 0.58) and 38 % (P = 0.09, ES = 0.73), respectively, with no difference between HIIE and MIE (P = 0.74, ES = 0.14). Changes in TAG were not related to energy expenditure during exercise or postprandial fat oxidation. Postprandial SBP (total-AUC pooled for both sexes) was lower in HIIE compared to CON (P = 0.01, ES = 0.68) and MIE (P = 0.02, ES = 0.60), with no difference between MIE and CON (P = 0.45, ES = 0.14). CONCLUSION: a single bout of HIIE and MIE, performed 1 h before an HFM, can meaningfully attenuate IAUC-TAG in girls but not boys. Additionally, HIIE, but not MIE, may lower postprandial SBP in normotensive adolescents.
Abstract.
Author URL.
Bond B, Gates PE, Jackman SR, Corless LM, Williams CA, Barker AR (2015). Exercise intensity and the protection from postprandial vascular dysfunction in adolescents.
Am J Physiol Heart Circ Physiol,
308(11), H1443-H1450.
Abstract:
Exercise intensity and the protection from postprandial vascular dysfunction in adolescents.
Acute exercise transiently improves endothelial function and protects the vasculature from the deleterious effects of a high-fat meal (HFM). We sought to identify whether this response is dependent on exercise intensity in adolescents. Twenty adolescents (10 male, 14.3 ± 0.3 yr) completed three 1-day trials: 1) rest (CON); 2) 8 × 1 min cycling at 90% peak power with 75 s recovery [high-intensity interval exercise (HIIE)]; and 3) cycling at 90% of the gas exchange threshold [moderate-intensity exercise (MIE)] 1 h before consuming a HFM (1.50 g/kg fat). Macrovascular and microvascular endothelial function was assessed before and immediately after exercise and 3 h after the HFM by flow-mediated dilation (FMD) and laser Doppler imaging [peak reactive hyperemia (PRH)]. FMD and PRH increased 1 h after HIIE [P < 0.001, effect size (ES) = 1.20 and P = 0.048, ES = 0.56] but were unchanged after MIE. FMD and PRH were attenuated 3 h after the HFM in CON (P < 0.001, ES = 1.78 and P = 0.02, ES = 0.59). FMD remained greater 3 h after the HFM in HIIE compared with MIE (P < 0.001, ES = 1.47) and CON (P < 0.001, ES = 2.54), and in MIE compared with CON (P < 0.001, ES = 1.40). Compared with CON, PRH was greater 3 h after the HFM in HIIE (P = 0.02, ES = 0.71) and MIE (P = 0.02, ES = 0.84), with no differences between HIIE and MIE (P = 0.72, ES = 0.16). Plasma triacylglycerol concentration and total antioxidant status concentration were not different between trials. We conclude that exercise intensity plays an important role in protecting the vasculature from the deleterious effects of a HFM. Performing HIIE may provide superior vascular benefits than MIE in adolescent groups.
Abstract.
Author URL.
Cockcroft EJ, Williams CA, Tomlinson O, Vlachopoulos D, Jackman S, Armstrong N, Barker AR (2015). High Intensity Interval Exercise is an Effective Alternative to Moderate Intensity Exercise for Improving Insulin Sensitivity in Adolescent Boys. Journal of Science and Medicine in Sport
Heneghan N, Adab P, Jackman S, Balanos G (2015). Musculoskeletal dysfunction in chronic obstructive pulmonary disease (COPD): an observational study.
International Journal of Therapy and Rehabilitation,
22(3), 119-128.
Abstract:
Musculoskeletal dysfunction in chronic obstructive pulmonary disease (COPD): an observational study
Background/Aims: Chronic obstructive pulmonary disease (COPD) is widely recognised as a multisystem disease that extends beyond the lung and can further impair functional capacity, including that of the musculoskeletal system. While it has been reported that these changes may contribute to exercise limitation and disability, there has been little research to describe the nature and extent of changes in the musculoskeletal system. Therefore, the aim of this study was to examine differences in posture, joint mobility and muscle sensitivity in subjects with COPD compared with a matched group of healthy subjects. A secondary aim was to explore whether a relationship exists between pulmonary function and musculoskeletal changes. Finally, the data were used to evaluate whether an association exists between cervicothoracic posture, joint mobility and muscle sensitivity, and having diagnosed COPD. Methods: a prospective observational study was reported in accordance with Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. Participants with stable COPD (n=33; mean±SD age: 67 ± 9 years; FEV1% predicted: 50.94 ±19.40%) and age-matched controls (n=55; mean±SD age: 67 ± 6 years; FEV1% predicted: 104.53 ±16.86%) were recruited from primary and secondary care sources. Pulmonary function and performance-based outcome measures (predictors) included posture, spinal joint mobility, and accessory respiratory muscle sensitivity. Sociodemographic data and confounding variables were assessed using questionnaires and performance-based measures. Results: Reduced thoracic (p
Abstract.
Krustrup P, Bradley PS, Christensen JF, Castagna C, Jackman S, Connolly L, Randers MB, Mohr M, Bangsbo J (2015). The Yo-Yo IE2 test: physiological response for untrained men versus trained soccer players.
Med Sci Sports Exerc,
47(1), 100-108.
Abstract:
The Yo-Yo IE2 test: physiological response for untrained men versus trained soccer players.
PURPOSE: This study aimed to examine the physical capacity and physiological response to the Yo-Yo Intermittent Endurance level 2 test (IE2) for untrained individuals (UTR) and trained male soccer players (TR) and to investigate the determinants of intense intermittent exercise performance. METHODS: Thirty-four healthy UTR males and 15 age-matched TR performed a maximal incremental treadmill test and a Yo-Yo IE2 test. Muscle biopsies and blood samples were obtained, and heart rate (HR) was measured before, during, and after tests. RESULTS: UTR had a 67% lower (P < 0.01) Yo-Yo IE2 performance (665 ± 271 vs 2027 ± 298 m; effect size (ES), 4.8), 34% lower V˙O2max (P < 0.01), and 19% lower resting muscle glycogen (P < 0.05) than those of TR. Blood lactate concentration and HR during the first 560 m of the Yo-Yo IE2 test were higher (P < 0.01) in UTR than those in TR (560 m, 7.4 ± 2.8 vs 2.4 ± 0.8 mM; ES, 1.7-2.8; 188 ± 11 vs 173 ± 8 bpm; ES, 0.9-1.5), with no differences at exhaustion. Time >95% HRmax was lower (P < 0.01) in UTR than that in TR (1.0 ± 1.1 vs 6.3 ± 2.9 min; ES, 3.1). Mean rates of muscle creatine phosphate utilization (16.5 ± 9.5 vs 4.3 ± 2.7 mmol·kg d.w·min), muscle lactate accumulation (16.8 ± 9.1 vs 4.2 ± 2.9 mmol·kg d.w.·min), and glycogen breakdown (29.6 ± 14.2 vs 7.7 ± 5.4 mmol·kg d.w.·min) were fourfold higher (P < 0.01; ES, 1.4-1.7) in UTR than those in TR. For UTR, correlations (P < 0.01) were observed between Yo-Yo IE2 performance and V˙O2max (r = 0.77), incremental treadmill test performance (r = 0.79), and muscle citrate synthase activity (r = 0.57) but not for TR (r = -0.12 to 0.50; P > 0.05). CONCLUSIONS: the Yo-Yo IE2 test was shown to possess high construct validity by showing large differences in performance, HR, and anaerobic metabolism between UTR and TR. In addition, V˙O2max seemed to be important for intermittent exercise performance in UTR but not for TR.
Abstract.
Author URL.
Bond B, Cockcroft EJ, Williams CA, Harris S, Gates PE, Jackman SR, Armstrong N, Barker AR (2015). Two weeks of high-intensity interval training improves novel but not traditional cardiovascular disease risk factors in adolescents.
Am J Physiol Heart Circ Physiol,
309(6), H1039-H1047.
Abstract:
Two weeks of high-intensity interval training improves novel but not traditional cardiovascular disease risk factors in adolescents.
High-intensity interval training (HIIT) improves traditional cardiovascular disease (CVD) risk factors in adolescents, but no study has identified the influence of HIIT on endothelial and autonomic function in this group. Thirteen 13- to 14-yr-old adolescents (6 girls) completed six HIIT sessions over 2 wk. Each training session consisted of eight to ten 1-min repetitions of cycling at 90% peak power interspersed with 75 s of unloaded cycling. Traditional (triglycerides, cholesterol, glucose, insulin, and blood pressure) and novel [flow-mediated dilation (FMD), heart rate variability (HRV)] CVD risk factors were assessed in a fasted and postprandial state before (PRE), 1 day after (POST-1D), and 3 days after (POST-3D) training. Aerobic fitness was determined PRE and POST-3D. Two weeks of HIIT had no effect on aerobic fitness or traditional CVD risk factors determined in the fasted or postprandial state (P > 0.15). Compared with PRE, fasted FMD was improved POST-1D [P = 0.003, effect size (ES) = 0.70] but not POST-3D (P = 0.32, ES = 0.22). Fasted FMD was greater POST-1D compared with POST-3D (P = 0.04, ES = 0.48). Compared with PRE, postprandial FMD was greater POST-1D (P < 0.001, ES = 1.01) and POST-3D (P = 0.01, ES = 0.60). Fasted HRV was greater POST-1D (P = 0.001, ES = 0.71) and POST-3D (P = 0.02, ES = 0.44). The test meal lowered HRV in all laboratory visits (P < 0.001, ES = 0.59), but there were no differences in postprandial HRV between visits (P > 0.32 for all). Two weeks of HIIT enhanced endothelial function and HRV without improvements in traditional CVD risk factors. However, most of this favorable adaptation was lost POST-3D, suggesting that regularly performing high-intensity exercise is needed to maintain these benefits.
Abstract.
Author URL.
2014
Barene S, Krustrup P, Jackman SR, Brekke OL, Holtermann A (2014). Do soccer and Zumba exercise improve fitness and indicators of health among female hospital employees? a 12-week RCT.
Scandinavian Journal of Medicine and Science in Sports,
24(6), 990-999.
Abstract:
Do soccer and Zumba exercise improve fitness and indicators of health among female hospital employees? a 12-week RCT
This randomized controlled study investigated the effectiveness of soccer and Zumba on fitness and health indicators in female participants recruited from a workplace. One hundred seven hospital employees were cluster-randomized to either a soccer group (SG), Zumba group (ZG), or control group (CG). Intervention effects for the two training groups were compared with CG. The training was conducted outside working hours as 2-3 1-h sessions per week for 12 weeks. Peak oxygen uptake (VO2peak), fat percentage, fat mass, bone mineral content, and plasma osteocalcin were measured before and after the intervention period. Based on intention-to-treat-analyses, SG significantly improved the VO2peak relative to body mass (5%; P=0.02) and decreased heart rate during 100-W cycle exercise (-7bpm; P=0.01), total body fat percentage (-1.1%; P=0.002), and total body fat mass (-1.0kg; P=0.001) compared with CG. ZG significantly improved the VO2peak relative to body mass (5%; P=0.03) and decreased total fat mass (-0.6kg; P
Abstract.
Barene S, Krustrup P, Jackman SR, Brekke OL, Holtermann A (2014). Do soccer and Zumba exercise improve fitness and indicators of health among female hospital employees? a 12-week RCT.
Scand J Med Sci Sports,
24(6), 990-999.
Abstract:
Do soccer and Zumba exercise improve fitness and indicators of health among female hospital employees? a 12-week RCT.
This randomized controlled study investigated the effectiveness of soccer and Zumba on fitness and health indicators in female participants recruited from a workplace. One hundred seven hospital employees were cluster-randomized to either a soccer group (SG), Zumba group (ZG), or control group (CG). Intervention effects for the two training groups were compared with CG. The training was conducted outside working hours as 2-3 1-h sessions per week for 12 weeks. Peak oxygen uptake (VO2peak ), fat percentage, fat mass, bone mineral content, and plasma osteocalcin were measured before and after the intervention period. Based on intention-to-treat-analyses, SG significantly improved the VO2peak relative to body mass (5%; P = 0.02) and decreased heart rate during 100-W cycle exercise (-7 bpm; P = 0.01), total body fat percentage (-1.1%; P = 0.002), and total body fat mass (-1.0 kg; P = 0.001) compared with CG. ZG significantly improved the VO2peak relative to body mass (5%; P = 0.03) and decreased total fat mass (-0.6 kg; P
Abstract.
Author URL.
Skiba PF, Jackman S, Clarke D, Vanhatalo A, Jones AM (2014). Effect of work and recovery durations on W' reconstitution during intermittent exercise.
Med Sci Sports Exerc,
46(7), 1433-1440.
Abstract:
Effect of work and recovery durations on W' reconstitution during intermittent exercise.
PURPOSE: We recently presented an integrating model of the curvature constant of the hyperbolic power-time relationship (W') that permits the calculation of the W' balance (W'BAL) remaining at any time during intermittent exercise. Although a relationship between recovery power and the rate of W' recovery was demonstrated, the effect of the length of work or recovery intervals remains unclear. METHODS: After determining VO2max, critical power, and W', 11 subjects completed six separate exercise tests on a cycle ergometer on different days, and in random order. Tests consisted of a period of intermittent severe-intensity exercise until the subject depleted approximately 50% of their predicted W'BAL, followed by a constant work rate (CWR) exercise bout until exhaustion. Work rates were kept constant between trials; however, either work or recovery durations during intermittent exercise were varied. The actual W' measured during the CWR (W'ACT) was compared with the amount of W' predicted to be available by the W'BAL model. RESULTS: Although some differences between W'BAL and W'ACT were noted, these amounted to only -1.6 ± 1.1 kJ when averaged across all conditions. The W'ACT was linearly correlated with the difference between VO2 at the start of CWR and VO2max (r = 0.79, P < 0.01). CONCLUSIONS: the W'BAL model provided a generally robust prediction of CWR W'. There may exist a physiological optimum formulation of work and recovery intervals such that baseline VO2 can be minimized, leading to an enhancement of subsequent exercise tolerance. These results may have important implications for athletic training and racing.
Abstract.
Author URL.
Skiba PF, Jackman S, Clarke D, Vanhatalo A, Jones AM (2014). Effect of work and recovery durations on W′ reconstitution during intermittent exercise.
Medicine and Science in Sports and Exercise,
46(7), 1433-1440.
Abstract:
Effect of work and recovery durations on W′ reconstitution during intermittent exercise
Purpose: We recently presented an integrating model of the curvature constant of the hyperbolic power-time relationship (W′) that permits the calculation of the W′ balance (W′BAL) remaining at any time during intermittent exercise. Although a relationship between recovery power and the rate of W′ recovery was demonstrated, the effect of the length of work or recovery intervals remains unclear. Methods: After determining V̇O2max, critical power, and W′, 11 subjects completed six separate exercise tests on a cycle ergometer on different days, and in random order. Tests consisted of a period of intermittent severe-intensity exercise until the subject depleted approximately 50% of their predicted W′BAL, followed by a constant work rate (CWR) exercise bout until exhaustion. Work rates were kept constant between trials; however, either work or recovery durations during intermittent exercise were varied. The actual W′ measured during the CWR (W′ACT) was compared with the amount of W′ predicted to be available by the W′BAL model. Results: Although some differences between W′BAL and W′ACT were noted, these amounted to only-1.6 ± 1.1 kJ when averaged across all conditions. The W′ACT was linearly correlated with the difference between V̇O2 at the start of CWR and V̇O2max (r = 0.79, P < 0.01). Conclusions: the W′BAL model provided a generally robust prediction of CWR W′. There may exist a physiological optimum formulation of work and recovery intervals such that baseline V̇O2 can be minimized, leading to an enhancement of subsequent exercise tolerance. These results may have important implications for athletic training and racing. © 2014 by the American College of Sports Medicine.
Abstract.
Connolly LJ, Scott S, Mohr M, Ermidis G, Julian R, Bangsbo J, Jackman SR, Bowtell JL, Davies RC, Hopkins SJ, et al (2014). Effects of small-volume soccer and vibration training on body composition, aerobic fitness, and muscular PCr kinetics for inactive women aged 20-45. Journal of Sport and Health Science
Connolly LJ, Scott S, Mohr M, Ermidis G, Julian R, Bangsbo J, Jackman SR, Bowtell JL, Davies RC, Hopkins SJ, et al (2014). Effects of small-volume soccer and vibration training on body composition, aerobic fitness, and muscular PCr kinetics for inactive women aged 20-45.
Journal of Sport and Health Science,
3(4), 284-292.
Abstract:
Effects of small-volume soccer and vibration training on body composition, aerobic fitness, and muscular PCr kinetics for inactive women aged 20-45
Purpose: the present study investigated the effects of 16 weeks of small-volume, small-sided soccer training soccer group (SG, n=13) and oscillating whole-body vibration training vibration group (VG, n=17) on body composition, aerobic fitness, and muscle PCr kinetics in healthy inactive premenopausal women in comparison with an inactive control group (CO, n=14). Methods: Training for SG and VG consisted of twice-weekly 15-min sessions with average heart rates (HRs) of ~155 and 90bpm respectively. Pre- and post-measurements of body composition (DXA), phosphocreatine (PCr) on- and off-kinetics, and HR measurements during standardised submaximal exercise were performed. Results: After 16 weeks of training in SG, fat percentage was lowered (p=0.03) by 1.7%±2.4% from 37.5%±6.9% to 35.8%±6.2% and the PCr decrease in the quadriceps during knee-extension ramp exercise was attenuated (4%±8%, p=0.04), with no changes in VG or CO (time-group effect: p=0.03 and p=0.03). Submaximal exercise HR was also reduced in SG after 16 weeks of training (6%±5% of HRmax, p=0.01). Conclusion: Short duration soccer training for 16 weeks appears to be sufficient to induce favourable changes in body composition and indicators of aerobic fitness and muscle oxidative capacity in untrained premenopausal women.
Abstract.
Bendiksen M, Williams CA, Hornstrup T, Clausen H, Kloppenborg J, Shumikhin D, Brito J, Horton J, Barene S, Jackman SR, et al (2014). Heart rate response and fitness effects of various types of physical education for 8- to 9-year-old schoolchildren.
European Journal of Sport Science,
14(8), 861-869.
Abstract:
Heart rate response and fitness effects of various types of physical education for 8- to 9-year-old schoolchildren
Abstract: the present study investigated the heart rate (HR) response to various types of physical education (PE) activities for 8- to 9-year-olds (five school classes, n = 93) and the fitness effects of a short-term PE training programme (three of the five classes, n = 59) with high compared to low-to-moderate aerobic intensity. HR was recorded during small-sided indoor soccer (SO), basketball (BB), unihockey (UH), circuit training (CT), walking (W) and Nintendo Wii Boxing (NWB) and Nintendo Wii Tennis (NWT). Maximal HR (HRmax) and physical fitness was determined by the Yo-Yo Intermittent Recovery Level 1 Children's test (YYIR1C) test. Following cluster randomisation, three classes were tested before and after 6 wks with 2 × 30 min/wk SO and UH lessons [high-intensity (HI), 2 classes, n = 39] or low-to-moderate intensity PE lessons (CON, 1 class, n = 20). Average HR in SO (76 ± 1% HRmax), BA (77 ± 1% HRmax) and UH (74 ± 1% HRmax) was higher (P < 0.05) than in CT (62 ± 1% HRmax), W (57 ± 1% HRmax), NWB (65 ± 2% HRmax) and NWT (57 ± 1% HRmax). Time with HR > 80% and 90% HRmax, respectively, was higher (P < 0.05) in SO (42 ± 4 and 12 ± 2%), BB (41 ± 5 and 13 ± 3%) and UH (34 ± 3 and 9 ± 2%) than in CT, W and NW (0–5%), with time >80% HRmax being higher (P < 0.05) in SO than UH. After 6 wk, YYIR1C performance was increased (P < 0.05) by 22% in HI (673 ± 57 to 821 ± 71 m), but unaltered in CON (674 ± 88 to 568 ± 81 m). HR 2 min into YYIR1C was lowered (P < 0.05) in HI after 6 wks (92.4 ± 0.8 to 89.1 ± 0.9% HRmax), but not in CON. In conclusion, ball games elicited high aerobic loading for young schoolchildren and a short-term, low-volume ball game PE-intervention improved physical fitness. Traditional PE sessions had no effects on intermittent exercise performance.
Abstract.
Bendiksen M, Williams CA, Hornstrup T, Clausen H, Kloppenborg J, Shumikhin D, Brito J, Horton J, Barene S, Jackman SR, et al (2014). Heart rate response and fitness effects of various types of physical education for 8- to 9-year-old schoolchildren. European Journal of Sport Science
Witard OC, Turner JE, Jackman SR, Kies AK, Jeukendrup AE, Bosch JA, Tipton KD (2014). High dietary protein restores overreaching induced impairments in leukocyte trafficking and reduces the incidence of upper respiratory tract infection in elite cyclists.
Brain, Behavior, and Immunity,
39, 211-219.
Abstract:
High dietary protein restores overreaching induced impairments in leukocyte trafficking and reduces the incidence of upper respiratory tract infection in elite cyclists
The present study examined whether a high protein diet prevents the impaired leukocyte redistribution in response to acute exercise caused by a large volume of high-intensity exercise training. Eight cyclists (VO2max: 64.2±6.5mLkg-1min-1) undertook two separate weeks of high-intensity training while consuming either a high protein diet (3gkg-1proteinBM-1day-1) or an energy and carbohydrate-matched control diet (1.5gkg-1proteinBM-1day-1). High-intensity training weeks were preceded by a week of normal-intensity training under the control diet. Leukocyte and lymphocyte sub-population responses to acute exercise were determined at the end of each training week. Self-reported symptoms of upper-respiratory tract infections (URTI) were monitored daily by questionnaire. Undertaking high-intensity training with a high protein diet restored leukocyte kinetics to similar levels observed during normal-intensity training: CD8+ TL mobilization (normal-intensity: 29,319±13,130cells/μL×~165min vs. high-intensity with protein: 26,031±17,474cells/μL×~165min, P>0.05), CD8+ TL egress (normal-intensity: 624±264cells/μL vs. high-intensity with protein: 597±478cells/μL, P>0.05). This pattern was driven by effector-memory populations mobilizing (normal-intensity: 6,145±6,227cells/μL×~165min vs. high-intensity with protein: 6,783±8,203cells/μL×~165min, P>0.05) and extravastating from blood (normal-intensity: 147±129cells/μL vs. high-intensity with protein: 165±192cells/μL, P>0.05). High-intensity training while consuming a high protein diet was associated with fewer symptoms of URTI compared to performing high-intensity training with a normal diet (P
Abstract.
Witard OC, Jackman SR, Breen L, Smith K, Selby A, Tipton KD (2014). Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise.
Am J Clin Nutr,
99(1), 86-95.
Abstract:
Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise.
BACKGROUND: the intake of whey, compared with casein and soy protein intakes, stimulates a greater acute response of muscle protein synthesis (MPS) to protein ingestion in rested and exercised muscle. OBJECTIVE: We characterized the dose-response relation of postabsorptive rates of myofibrillar MPS to increasing amounts of whey protein at rest and after exercise in resistance-trained, young men. DESIGN: Volunteers (n = 48) consumed a standardized, high-protein (0.54 g/kg body mass) breakfast. Three hours later, a bout of unilateral exercise (8 × 10 leg presses and leg extensions; 80% one-repetition maximum) was performed. Volunteers ingested 0, 10, 20, or 40 g whey protein isolate immediately (~10 min) after exercise. Postabsorptive rates of myofibrillar MPS and whole-body rates of phenylalanine oxidation and urea production were measured over a 4-h postdrink period by continuous tracer infusion of labeled [(13)C6] phenylalanine and [(15)N2] urea. RESULTS: Myofibrillar MPS (mean ± SD) increased (P < 0.05) above 0 g whey protein (0.041 ± 0.015%/h) by 49% and 56% with the ingestion of 20 and 40 g whey protein, respectively, whereas no additional stimulation was observed with 10 g whey protein (P > 0.05). Rates of phenylalanine oxidation and urea production increased with the ingestion of 40 g whey protein. CONCLUSIONS: a 20-g dose of whey protein is sufficient for the maximal stimulation of postabsorptive rates of myofibrillar MPS in rested and exercised muscle of ~80-kg resistance-trained, young men. A dose of whey protein >20 g stimulates amino acid oxidation and ureagenesis. This trial was registered at http://www.isrctn.org/ as ISRCTN92528122.
Abstract.
Author URL.
Helge EW, Randers MB, Hornstrup T, Nielsen JJ, Blackwell J, Jackman SR, Krustrup P (2014). Street football is a feasible health-enhancing activity for homeless men: Biochemical bone marker profile and balance improved.
Scandinavian Journal of Medicine and Science in Sports,
24(SUPPL.1), 122-129.
Abstract:
Street football is a feasible health-enhancing activity for homeless men: Biochemical bone marker profile and balance improved
This case-control study investigated the feasibility of street football as a health-enhancing activity for homeless men, specifically the musculoskeletal effects of 12 weeks of training. Twenty-two homeless men participated in the football group (FG) and 10 served as controls (C). Plasma osteocalcin, TRACP5b, leptin, and postural balance were measured, and whole-body DXA scanning was performed. The attendance rate was 75% (2.2±0.7 sessions per week). During 60min of training, the total distance covered was 5534±610m, with 1040±353, 2744±671, and 864±224m covered by high-intensity, low-intensity, and backwards/sideways running, respectively. In FG, osteocalcin increased by 27% from 20.1±11.1 to 25.6±11.8ng/mL (P=0.007). Postural balance increased by 39% (P=0.004) and 46% (P=0.006) in right and left leg. Trunk bone mineral density increased by 1.0% from 0.959±0.095 to 0.969±0.090g/cm2 (P=0.02). No effects were observed in C. In conclusion, street football appears to be a feasible training activity with musculoskeletal health benefits for homeless men. The attendance rate and the training intensity were high, and 12 weeks of training resulted in a substantial anabolic response in bone metabolism. Postural balance improved markedly, and the overall risk of falling, and hospitalization due to sudden trauma, could be reduced by street football for homeless men. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Abstract.
2013
Hansen PR, Andersen LJ, Rebelo AN, Brito J, Hornstrup T, Schmidt JF, Jackman SR, Mota J, Rêgo C, Oliveira J, et al (2013). Cardiovascular effects of 3 months of football training in overweight children examined by comprehensive echocardiography: a pilot study.
Journal of Sports Sciences,
31(13), 1432-1440.
Abstract:
Cardiovascular effects of 3 months of football training in overweight children examined by comprehensive echocardiography: a pilot study
We examined effects of a 3-month football training programme in overweight children using comprehensive echocardiography and peripheral arterial tonometry. Twenty preadolescent overweight children (17 boys, 3 girls aged 8-12 yrs; body mass index [BMI] ≥ 85th percentile) participated in a structured 3-month football training programme, consisting of 4 weekly 60-90 min sessions with mean heart rate (HR) > 80% of HRmax (football group, FG). A parallel control group (CG) included 11 children (7 boys, 4 girls) of equivalent age from an obesity clinic. After 3 months, systolic blood pressure was unchanged in FG, but had increased in CG (112 [s 6] vs. 122 [10] mmHg, P = 0.02). FG demonstrated increased left ventricular (LV) posterior wall diameter (0.60 [0.07] vs. 0.68 [0.10] cm, P < 0.001) and an improved right ventricular systolic function determined by tricuspid annular plane systolic excursion (TAPSE, 2.01 [0.29] vs. 2.27 [0.28] cm, P = 0.003). Measures of LV systolic function showed only discrete alterations and two-dimensional (2D) global strain was not changed. After 3 months, global isovolumetric relaxation time (IVRTglobal) had increased in FG (64.0 [7.5] vs. 73.9 [9.4] ms, P < 0.001) while other examined LV diastolic function variables were not altered. No echocardiographic changes were observed in CG. Between-group differences in pre-post delta values were observed for systolic blood pressure, TAPSE, and IVRTglobal (P = 0.02-0.03). We conclude that short-term football training may have positive structural and functional effects on the cardiovascular system in overweight preadolescent children. © 2013 Taylor & Francis.
Abstract.
Hansen PR, Andersen LJ, Rebelo AN, Brito J, Hornstrup T, Schmidt JF, Jackman SR, Mota J, Rêgo C, Oliveira J, et al (2013). Cardiovascular effects of 3 months of football training in overweight children examined by comprehensive echocardiography: a pilot study.
J Sports Sci,
31(13), 1432-1440.
Abstract:
Cardiovascular effects of 3 months of football training in overweight children examined by comprehensive echocardiography: a pilot study.
We examined effects of a 3-month football training programme in overweight children using comprehensive echocardiography and peripheral arterial tonometry. Twenty preadolescent overweight children (17 boys, 3 girls aged 8-12 yrs; body mass index [BMI] ≥ 85(th) percentile) participated in a structured 3-month football training programme, consisting of 4 weekly 60-90 min sessions with mean heart rate (HR) > 80% of HRmax (football group, FG). A parallel control group (CG) included 11 children (7 boys, 4 girls) of equivalent age from an obesity clinic. After 3 months, systolic blood pressure was unchanged in FG, but had increased in CG (112 [s 6] vs. 122 [10] mmHg, P = 0.02). FG demonstrated increased left ventricular (LV) posterior wall diameter (0.60 [0.07] vs. 0.68 [0.10] cm, P < 0.001) and an improved right ventricular systolic function determined by tricuspid annular plane systolic excursion (TAPSE, 2.01 [0.29] vs. 2.27 [0.28] cm, P = 0.003). Measures of LV systolic function showed only discrete alterations and two-dimensional (2D) global strain was not changed. After 3 months, global isovolumetric relaxation time (IVRTglobal) had increased in FG (64.0 [7.5] vs. 73.9 [9.4] ms, P < 0.001) while other examined LV diastolic function variables were not altered. No echocardiographic changes were observed in CG. Between-group differences in pre-post delta values were observed for systolic blood pressure, TAPSE, and IVRTglobal (P = 0.02-0.03). We conclude that short-term football training may have positive structural and functional effects on the cardiovascular system in overweight preadolescent children.
Abstract.
Author URL.
Wylie LJ, Mohr M, Krustrup P, Jackman SR, Ermιdis G, Kelly J, Black MI, Bailey SJ, Vanhatalo A, Jones AM, et al (2013). Dietary nitrate supplementation improves team sport-specific intense intermittent exercise performance.
European Journal of Applied Physiology,
113(7), 1673-1684.
Abstract:
Dietary nitrate supplementation improves team sport-specific intense intermittent exercise performance
Recent studies have suggested that dietary inorganic nitrate (NO 3- ) supplementation may improve muscle efficiency and endurance exercise tolerance but possible effects during team sport-specific intense intermittent exercise have not been examined. We hypothesized that NO 3- supplementation would enhance high-intensity intermittent exercise performance. Fourteen male recreational team-sport players were assigned in a double-blind, randomized, crossover design to consume 490 mL of concentrated, nitrate-rich beetroot juice (BR) and nitrate-depleted placebo juice (PL) over ∼30 h preceding the completion of a Yo-Yo intermittent recovery level 1 test (Yo-Yo IR1). Resting plasma nitrite concentration ([NO 2- ]) was ∼400 % greater in BR compared to PL. Plasma [NO 2- ] declined by 20 % in PL (P < 0.05) and by 54 % in BR (P < 0.05) from pre-exercise to end-exercise. Performance in the Yo-Yo IR1 was 4.2 % greater (P < 0.05) with BR (1,704 ± 304 m) compared to PL (1,636 ± 288 m). Blood [lactate] was not different between BR and PL, but the mean blood [glucose] was lower (3.8 ± 0.8 vs. 4.2 ± 1.1 mM, P < 0.05) and the rise in plasma [K + ] tended to be reduced in BR compared to PL (P = 0.08). These findings suggest that NO 3- supplementation may promote NO production via the nitrate-nitrite-NO pathway and enhance Yo-Yo IR1 test performance, perhaps by facilitating greater muscle glucose uptake or by better maintaining muscle excitability. Dietary NO 3- supplementation improves performance during intense intermittent exercise and may be a useful ergogenic aid for team sports players. © 2013 Springer-Verlag Berlin Heidelberg.
Abstract.
Wylie LJ, Mohr M, Krustrup P, Jackman SR, Ermιdis G, Kelly J, Black MI, Bailey SJ, Vanhatalo A, Jones AM, et al (2013). Dietary nitrate supplementation improves team sport-specific intense intermittent exercise performance.
Eur J Appl Physiol,
113(7), 1673-1684.
Abstract:
Dietary nitrate supplementation improves team sport-specific intense intermittent exercise performance.
Recent studies have suggested that dietary inorganic nitrate (NO₃(-)) supplementation may improve muscle efficiency and endurance exercise tolerance but possible effects during team sport-specific intense intermittent exercise have not been examined. We hypothesized that NO₃(-) supplementation would enhance high-intensity intermittent exercise performance. Fourteen male recreational team-sport players were assigned in a double-blind, randomized, crossover design to consume 490 mL of concentrated, nitrate-rich beetroot juice (BR) and nitrate-depleted placebo juice (PL) over ~30 h preceding the completion of a Yo-Yo intermittent recovery level 1 test (Yo-Yo IR1). Resting plasma nitrite concentration ([NO₂(-)]) was ~400% greater in BR compared to PL. Plasma [NO₂(-)] declined by 20% in PL (P < 0.05) and by 54 % in BR (P < 0.05) from pre-exercise to end-exercise. Performance in the Yo-Yo IR1 was 4.2% greater (P < 0.05) with BR (1,704 ± 304 m) compared to PL (1,636 ± 288 m). Blood [lactate] was not different between BR and PL, but the mean blood [glucose] was lower (3.8 ± 0.8 vs. 4.2 ± 1.1 mM, P < 0.05) and the rise in plasma [K(+)] tended to be reduced in BR compared to PL (P = 0.08). These findings suggest that NO₃(-) supplementation may promote NO production via the nitrate-nitrite-NO pathway and enhance Yo-Yo IR1 test performance, perhaps by facilitating greater muscle glucose uptake or by better maintaining muscle excitability. Dietary NO₃(-) supplementation improves performance during intense intermittent exercise and may be a useful ergogenic aid for team sports players.
Abstract.
Author URL.
Witard OC, Turner JE, Jackman SR, Kies AK, Jeukendrup AE, Bosch JA, Tipton KD (2013). High dietary protein restores overreaching induced impairments in leukocyte trafficking and reduces the incidence of upper respiratory tract infection in elite cyclists. Brain, Behavior, and Immunity
Jackman SR, Scott S, Randers MB, Ørntoft C, Blackwell J, Abdossaleh Z, Helge EW, Mohr M, Krustrup P (2013). Musculoskeletal health profile for elite female footballers versus untrained young women before and after 16 weeks of football training.
Journal of Sports Sciences,
31(13), 1468-1474.
Abstract:
Musculoskeletal health profile for elite female footballers versus untrained young women before and after 16 weeks of football training
We investigated the musculoskeletal health profile of elite female football players (ET) in comparison to untrained (UT) young women subjected to 16 weeks of football training (2 × 1 h per week). DXA scans, blood sampling, sprint testing and Flamingo postural balance testing were carried out for 27 Danish national team players and 28 untrained women, with eight women being tested after training. At baseline total BMD and BMC were 13% (1.305 ± 0.050 versus 1.159 ± 0.056 g · cm-2) and 23% (3047 ± 235 versus 2477 ± 526 g) higher (P
Abstract.
Jackman SR, Scott S, Randers MB, Orntoft C, Blackwell J, Zar A, Helge EW, Mohr M, Krustrup P (2013). Musculoskeletal health profile for elite female footballers versus untrained young women before and after 16 weeks of football training.
J Sports Sci,
31(13), 1468-1474.
Abstract:
Musculoskeletal health profile for elite female footballers versus untrained young women before and after 16 weeks of football training.
We investigated the musculoskeletal health profile of elite female football players (ET) in comparison to untrained (UT) young women subjected to 16 weeks of football training (2 × 1 h per week). DXA scans, blood sampling, sprint testing and Flamingo postural balance testing were carried out for 27 Danish national team players and 28 untrained women, with eight women being tested after training. At baseline total BMD and BMC were 13% (1.305 ± 0.050 versus 1.159 ± 0.056 g · cm(-2)) and 23% (3047 ± 235 versus 2477 ± 526 g) higher (P
Abstract.
Author URL.
Krustrup P, Randers MB, Andersen LJ, Jackman SR, Bangsbo J, Hansen PR (2013). Soccer improves fitness and attenuates cardiovascular risk factors in hypertensive men.
Medicine and Science in Sports and Exercise,
45(3), 553-560.
Abstract:
Soccer improves fitness and attenuates cardiovascular risk factors in hypertensive men
INTRODUCTION: the present study investigated the fitness and health effects of medium-term soccer training for untrained hypertensive middle-age men. METHODS: Thirty-three untrained males (31-54 yr) with mild-to-moderate hypertension were randomized 2:1 to a soccer training group (STG, two 1-h sessions per week, n = 22, 68% on medication) and a doctor advice group receiving traditional physician-guided recommendations on cardiovascular risk factor modification (DAG, n = 11, 73% on medication). Two-way repeated-measures ANOVA time-group statistics was applied. RESULTS: During soccer training, average HR was 155 ± 9 bpm or 85% ± 7% HRmax. In STG, systolic and diastolic blood pressures decreased (P < 0.01) over 6 months from 151 ± 10 to 139 ± 10 mm Hg and from 92 ± 7 to 84 ± 6 mm Hg, respectively, with smaller (P < 0.05) decreases in DAG (from 153 ± 8 to 145 ± 8 mm Hg and from 96 ± 6 to 93 ± 6 mm Hg, respectively). In STG, VO2max increased (P < 0.01) from 32.6 ± 4.9 to 35.4 ± 6.6 mL·min·kg and relative VO2 during cycling at 100 W was lowered (P < 0.05) from 55% ± 7% to 50% ± 8% VO2max over 6 months, with no changes in DAG. In STG, resting HR was lowered by 8 ± 11 bpm (P < 0.05), and the augmentation index (a measure of arterial stiffness) was lowered (P < 0.05) by 7.3 ± 14.0 over 6 months, with no change in DAG. CONCLUSIONS: Six months of soccer training improved aerobic fitness, reduced blood pressure, and resulted in an array of other favorable effects on cardiovascular risk profile for untrained middle-age hypertensive men. Soccer training, therefore, may be a better nonpharmacological treatment for hypertensive men than traditional physician-guided advice. Copyright © 2013 by the American College of Sports Medicine.
Abstract.
Krustrup P, Randers MB, Andersen LJ, Jackman SR, Bangsbo J, Hansen PR (2013). Soccer improves fitness and attenuates cardiovascular risk factors in hypertensive men.
Med Sci Sports Exerc,
45(3), 553-560.
Abstract:
Soccer improves fitness and attenuates cardiovascular risk factors in hypertensive men.
INTRODUCTION: the present study investigated the fitness and health effects of medium-term soccer training for untrained hypertensive middle-age men. METHODS: Thirty-three untrained males (31-54 yr) with mild-to-moderate hypertension were randomized 2:1 to a soccer training group (STG, two 1-h sessions per week, n = 22, 68% on medication) and a doctor advice group receiving traditional physician-guided recommendations on cardiovascular risk factor modification (DAG, n = 11, 73% on medication). Two-way repeated-measures ANOVA time-group statistics was applied. RESULTS: During soccer training, average HR was 155 ± 9 bpm or 85% ± 7% HRmax. In STG, systolic and diastolic blood pressures decreased (P < 0.01) over 6 months from 151 ± 10 to 139 ± 10 mm Hg and from 92 ± 7 to 84 ± 6 mm Hg, respectively, with smaller (P < 0.05) decreases in DAG (from 153 ± 8 to 145 ± 8 mm Hg and from 96 ± 6 to 93 ± 6 mm Hg, respectively). In STG, V˙O2max increased (P < 0.01) from 32.6 ± 4.9 to 35.4 ± 6.6 mL·min-1·kg-1 and relative V˙O2 during cycling at 100 W was lowered (P < 0.05) from 55% ± 7% to 50% ± 8% V˙O2max over 6 months, with no changes in DAG. In STG, resting HR was lowered by 8 ± 11 bpm (P < 0.05), and the augmentation index (a measure of arterial stiffness) was lowered (P < 0.05) by 7.3 ± 14.0 over 6 months, with no change in DAG. CONCLUSIONS: Six months of soccer training improved aerobic fitness, reduced blood pressure, and resulted in an array of other favorable effects on cardiovascular risk profile for untrained middle-age hypertensive men. Soccer training, therefore, may be a better nonpharmacological treatment for hypertensive men than traditional physician-guided advice.
Abstract.
Author URL.
2012
Witard OC, Turner JE, Jackman SR, Tipton KD, Jeukendrup AE, Kies AK, Bosch JA (2012). High-intensity training reduces CD8<sup>+</sup> T-cell redistribution in response to exercise.
Medicine and Science in Sports and Exercise,
44(9), 1689-1697.
Abstract:
High-intensity training reduces CD8+ T-cell redistribution in response to exercise
Purpose: We examined whether exercise-induced lymphocytosis and lymphocytopenia are impaired with high-intensity training. Methods: Eight trained cyclists (V̇O2max = 64.2 ± 6.5 mL•kg -1•min-1) undertook 1 wk of normal-intensity training and a second week of high-intensity training. On day 7 of each week, participants performed a cycling task, consisting of 120 min of submaximal exercise followed by a 45-min time trial. Blood was collected before, during, and after exercise. CD8+ T lymphocytes (CD8TLs) were identified, as well as CD8TL subpopulations on the basis of CD45RA and CD27 expression. Results: High-intensity training (18,577 ± 10,984 cells per microliter × ∼165 min) was associated with a smaller exercise-induced mobilization of CD8+TLs compared with normal-intensity training (28,473 ± 16,163 cells per microliter × ∼165 min, P = 0.09). The response of highly cytotoxic CD8+TLs (CD45RA+CD27 -) to exercise was smaller after 1 wk of high-intensity training (3144 ± 924 cells per microliter × ∼165 min) compared with normal-intensity training (6417 ± 2143 cells per microliter × ∼165 min, P < 0.05). High-intensity training reduced postexercise CD8+TL lymphocytopenia (-436 ± 234 cells per microliter) compared with normal-intensity training (-630 ± 320 cells per microliter, P < 0.05). This was driven by a reduced egress of naive CD8+TLs (CD27+CD45RA+). High-intensity training was associated with reduced plasma epinephrine (-37%) and cortisol (-15%) responses (P < 0.05). Conclusions: High-intensity training impaired CD8+TL mobilization and egress in response to exercise. Highly cytotoxic CD8 +TLs were primarily responsible for the reduced mobilization of CD8+TLs, which occurred in parallel with smaller neuroendocrine responses. The reduced capacity for CD8+TLs to leave blood after exercise with high-intensity training was accounted for primarily by naive, and also, highly cytotoxic CD8+TLs. This impaired CD8+TL redistribution in athletes undertaking intensified training may imply reduced immune surveillance. © 2012 by the American College of Sports Medicine.
Abstract.
Andersen TB, Bendiksen M, Pedersen JM, Ørntoft C, Brito J, Jackman SR, Williams CA, Krustrup P (2012). Kicking velocity and physical, technical, tactical match performance for U18 female football players - Effect of a new ball.
Human Movement Science,
31(6), 1624-1638.
Abstract:
Kicking velocity and physical, technical, tactical match performance for U18 female football players - Effect of a new ball
We investigated kicking velocity and physical, technical, and tactical match performance for under-18 (U18) female football players and evaluated the effect of using a newly developed lighter smaller ball. Ten regional league teams participated. Maximal ball velocity was 4±1% higher when kicking the new ball (NB) compared with the standard ball (SB) in a laboratory testing situation (23.2±0.4 vs. 22.4±0.3ms-1; p.05), but lower-limb muscular RPE was lower with NB (4.2±0.4 vs. 5.2±0.3; p.05). High-intensity running decreased (p.05). In conclusion, physiological demands were high in youth female football games, and decrements in running performance occurred towards the end of games. The players kicked faster and reported lower muscular exertion during games played with a lighter smaller ball, but locomotor activities, heart rate and overall technical-tactical game performance remained unaffected. © 2012 Elsevier B.V.
Abstract.
Andersen TB, Bendiksen M, Pedersen JM, Ørntoft C, Brito J, Jackman SR, Williams CA, Krustrup P (2012). Kicking velocity and physical, technical, tactical match performance for U18 female football players--effect of a new ball.
Hum Mov Sci,
31(6), 1624-1638.
Abstract:
Kicking velocity and physical, technical, tactical match performance for U18 female football players--effect of a new ball.
We investigated kicking velocity and physical, technical, and tactical match performance for under-18 (U18) female football players and evaluated the effect of using a newly developed lighter smaller ball. Ten regional league teams participated. Maximal ball velocity was 4±1% higher when kicking the new ball (NB) compared with the standard ball (SB) in a laboratory testing situation (23.2±0.4 vs. 22.4±0.3 ms(-1); p.05), but lower-limb muscular RPE was lower with NB (4.2±0.4 vs. 5.2±0.3; p.05). High-intensity running decreased (p.05). In conclusion, physiological demands were high in youth female football games, and decrements in running performance occurred towards the end of games. The players kicked faster and reported lower muscular exertion during games played with a lighter smaller ball, but locomotor activities, heart rate and overall technical-tactical game performance remained unaffected.
Abstract.
Author URL.
2011
Witard OC, Jackman SR, Kies AK, Jeukendrup AE, Tipton KD (2011). Effect of increased dietary protein on tolerance to intensified training.
Med Sci Sports Exerc,
43(4), 598-607.
Abstract:
Effect of increased dietary protein on tolerance to intensified training.
PURPOSE: the purpose of the present study was to examine the effect of increased protein intake on short-term decrements in endurance performance during a block of high-intensity training. METHODS: Trained male cyclists (VO(2max) = 64.2 ± 6.5 mL·kg(-1)·min(-1)) completed two 3-wk trials both divided equally into normal (NOR), intensified (INT), and recovery (REC) training. In a counterbalanced crossover experimental design, cyclists received either a high-protein (PRO; 3 g protein·kg(-1) body mass (BM)·d(-1)) or a normal diet (CON; 1.5 g protein·kg(-1) BM·d(-1)) during INT and REC. Dietary carbohydrate content remained constant at 6 g·kg(-1) BM·d(-1). Energy balance was maintained during each training week. Endurance performance was assessed with a VO(2max) test and a preloaded time trial. Alterations in blood metabolite responses to exercise were measured at rest, during, and after exercise. Cyclists completed the Daily Analysis of Life Demands for Athletes (DALDA) questionnaire each day. RESULTS: Increased dietary protein intake led to a possible attenuation (4.3%; 90% confidence limits ×/÷5.4%) in the decrement in time trial performance after a block of high-intensity training compared with NOR (PRO = 2639 ± 350 s; CON = 2555 ± 313 s). Restoration of endurance performance during recovery training possibly benefited (2.0%; ×/÷4.9%) from additional protein intake. Frequency of symptoms of stress described as "worse than normal" reported after a block of high-intensity training was very likely (97%) attenuated (17; ±11 AUC of "a" scores part B, DALDA for INT + REC) by increasing the protein content of the diet. No discernable changes in blood metabolite concentrations were observed in PRO. CONCLUSIONS: Additional protein intake reduced symptoms of psychological stress and may result in a worthwhile amelioration of the performance decline experienced during a block of high-intensity training.
Abstract.
Author URL.
Breen L, Philp A, Witard OC, Jackman SR, Selby A, Smith K, Baar K, Tipton KD (2011). The influence of carbohydrate-protein co-ingestion following endurance exercise on myofibrillar and mitochondrial protein synthesis.
Journal of Physiology,
589(16), 4011-4025.
Abstract:
The influence of carbohydrate-protein co-ingestion following endurance exercise on myofibrillar and mitochondrial protein synthesis
The aim of the present study was to determine mitochondrial and myofibrillar muscle protein synthesis (MPS) when carbohydrate (CHO) or carbohydrate plus protein (C+P) beverages were ingested following prolonged cycling exercise. The intracellular mechanisms thought to regulate MPS were also investigated. In a single-blind, cross-over study, 10 trained cyclists (age 29 ± 6 years, 66.5 ± 5.1 ml kg -1 min -1) completed two trials in a randomized order. Subjects cycled for 90 min at 77 ± 1% before ingesting a CHO (25 g of carbohydrate) or C+P (25 g carbohydrate + 10 g whey protein) beverage immediately and 30 min post-exercise. A primed constant infusion of l-[ring- 13C 6]phenylalanine began 1.5h prior to exercise and continued until 4h post-exercise. Muscle biopsy samples were obtained to determine myofibrillar and mitochondrial MPS and the phosphorylation of intracellular signalling proteins. Arterialized blood samples were obtained throughout the protocol. Plasma amino acid and urea concentrations increased following ingestion of C+P only. Serum insulin concentration increased more for C+P than CHO. Myofibrillar MPS was ∼35% greater for C+P compared with CHO (0.087 ± 0.007 and 0.057 ± 0.006%h -1, respectively; P= 0.025). Mitochondrial MPS rates were similar for C+P and CHO (0.082 ± 0.011 and 0.086 ± 0.018%h -1, respectively). mTOR Ser2448 phosphorylation was greater for C+P compared with CHO at 4h post-exercise (P < 0.05). p70S6K Thr389 phosphorylation increased at 4h post-exercise for C+P (P < 0.05), whilst eEF2 Thr56 phosphorylation increased by ∼40% at 4h post-exercise for CHO only (P < 0.01). The present study demonstrates that the ingestion of protein in addition to carbohydrate stimulates an increase in myofibrillar, but not mitochondrial, MPS following prolonged cycling. These data indicate that the increase in myofibrillar MPS for C+P could, potentially, be mediated through p70S6K, downstream of mTOR, which in turn may suppress the rise in eEF2 on translation elongation. © 2011 the Authors. Journal compilation © 2011 the Physiological Society.
Abstract.
Breen L, Philp A, Witard OC, Jackman SR, Selby A, Smith K, Baar K, Tipton KD (2011). The influence of carbohydrate-protein co-ingestion following endurance exercise on myofibrillar and mitochondrial protein synthesis.
J Physiol,
589(Pt 16), 4011-4025.
Abstract:
The influence of carbohydrate-protein co-ingestion following endurance exercise on myofibrillar and mitochondrial protein synthesis.
The aim of the present study was to determine mitochondrial and myofibrillar muscle protein synthesis (MPS) when carbohydrate (CHO) or carbohydrate plus protein (C+P) beverages were ingested following prolonged cycling exercise. The intracellular mechanisms thought to regulate MPS were also investigated. In a single-blind, cross-over study, 10 trained cyclists (age 29 ± 6 years, VO2max 66.5 ± 5.1 ml kg(−1) min(−1)) completed two trials in a randomized order. Subjects cycled for 90 min at 77 ± 1% VO2max before ingesting a CHO (25 g of carbohydrate) or C+P (25 g carbohydrate + 10 g whey protein) beverage immediately and 30 min post-exercise. A primed constant infusion of L-[ring-(13)C6]phenylalanine began 1.5 h prior to exercise and continued until 4 h post-exercise. Muscle biopsy samples were obtained to determine myofibrillar and mitochondrial MPS and the phosphorylation of intracellular signalling proteins. Arterialized blood samples were obtained throughout the protocol. Plasma amino acid and urea concentrations increased following ingestion of C+P only. Serum insulin concentration increased more for C+P than CHO. Myofibrillar MPS was ∼35% greater for C+P compared with CHO (0.087 ± 0.007 and 0.057 ± 0.006% h(−1), respectively; P = 0.025). Mitochondrial MPS rates were similar for C+P and CHO (0.082 ± 0.011 and 0.086 ± 0.018% h(−1), respectively). mTOR(Ser2448) phosphorylation was greater for C+P compared with CHO at 4 h post-exercise (P < 0.05). p70S6K(Thr389) phosphorylation increased at 4 h post-exercise for C+P (P < 0.05), whilst eEF2(Thr56) phosphorylation increased by ∼40% at 4 h post-exercise for CHO only (P < 0.01). The present study demonstrates that the ingestion of protein in addition to carbohydrate stimulates an increase in myofibrillar, but not mitochondrial, MPS following prolonged cycling. These data indicate that the increase in myofibrillar MPS for C+P could, potentially, be mediated through p70S6K, downstream of mTOR, which in turn may suppress the rise in eEF2 on translation elongation.
Abstract.
Author URL.
2010
Jackman SR, Witard OC, Jeukendrup AE, Tipton KD (2010). Branched-chain amino acid ingestion can ameliorate soreness from eccentric exercise.
Med Sci Sports Exerc,
42(5), 962-970.
Abstract:
Branched-chain amino acid ingestion can ameliorate soreness from eccentric exercise.
PURPOSE: the purpose of this study was to examine the role of branched-chain amino acid (BCAA) supplementation during recovery from intense eccentric exercise. METHODS: Twenty-four non-weight-trained males were assigned to one of two groups: one group (supplementary, SUP) ingested BCAA beverages (n = 12); the second group (placebo, PLA) ingested artificially flavored water (n = 12). Diet was controlled throughout the testing period to match habitual intake. The eccentric exercise protocol consisted of 12 x 10 repetitions of unilateral eccentric knee extension exercise at 120% concentric one repetition maximum. On the day of the exercise, supplements were consumed 30 min before exercise, 1.5 h after exercise, between lunch and dinner, and before bed. On the following 2 d, four supplements were consumed between meals. Muscle soreness, muscle function, and putative blood markers of muscle damage were assessed before and after (1, 8, 24, 48, and 72 h) exercise. RESULTS: Muscle function decreased after the eccentric exercise (P < 0.0001), but the degree of force loss was unaffected by BCAA ingestion (51% +/- 3% with SUP vs -48% +/- 7% with PLA). A decrease in flexed muscle soreness was observed in SUP compared with PLA at 48 h (21 +/- 3 mm vs 32 +/- 3 mm, P = 0.02) and 72 h (17 +/- 3 mm vs 27 +/- 4 mm, P = 0.038). Flexed muscle soreness, expressed as area under the curve, was lower in SUP than in PLA (P = 0.024). CONCLUSIONS: BCAA supplementation may attenuate muscle soreness, but it does not ameliorate eccentric exercise-induced decrements in muscle function or increases in reputed blood markers of muscle damage, when consumed before exercise and for 3 d after an eccentric exercise bout.
Abstract.
Author URL.
2008
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