Background: the repeated act of heading has been implicated in the link between football participation and risk of neurodegenerative disease, and acutely alters cerebrovascular outcomes in men. This study assessed whether exposure to a realistic number of headers acutely influences indices of cerebral blood flow regulation in female footballers. Methods: Nineteen female players completed a heading trial and seated control trial on two separate days. The heading trial involved six headers in one hour (one every 10 minutes), with the ball travelling at 40 ± 5 km/h. Cerebrovascular reactivity to hypercapnia and hypocapnia was determined using serial breath holding and hyperventilation attempts. Dynamic cerebral autoregulation (dCA) was assessed by scrutinizing the relationship between cerebral blood flow and mean arterial blood pressure during 5 minutes of squat stand maneuvers at 0.05 Hz. Neurovascular coupling (NVC) was quantified as the posterior cerebral artery blood velocity response to a visual search task. These outcomes were assessed before and one hour after the heading or control trial. Results: No significant time by trial interaction was present for the hypercapnic (P=0.48, ηp2=0.05) and hypocapnic (P=0.47, ηp2=0.06) challenge. Similarly, no significant interaction effect was present for any metric of dCA (P>0.12, ηp20.14, ηp2

Rugby Union (rugby) is a full-contact team sport characterised by frequent collision events. Over one third (2.7 million) of global rugby participants are women and girls. Yet, most rugby research, laws, and regulations are derived from the men’s game with limited transferability to the women’s game. This includes research focused on injury and concussion management. Greater insights are urgently required to enable appropriate adaptations and support for all rugby participants. Therefore, this paper presents the protocol for a project that sought to gather insights into the understanding, experiences, and attitudes of players and coaches in women’s rugby regarding key issues of concussion, injury, and training for injury prevention, as well as the implications of the menstrual cycle for training and performance. From August 2020 to November 2020, online, open, cross-sectional surveys for players and coaches were distributed globally through rugby governing bodies and women’s rugby social media platforms using snowball sampling. Survey responses were recorded anonymously via a GDPR-compliant online survey platform, JISC (jisc.ac.uk, Bristol, England). Participant eligibility included being ≥18 years and either actively playing or coaching women’s rugby 15s and/or sevens, or having done so in the past decade, at any level, in any country. To enhance the number and accuracy of responses, the survey was professionally translated into eight additional languages. A total of 1596 participants from 62 countries (27 ± 6 years; 7.5 ± 5.1 years of playing experience) and 296 participants from 37 countries (mean age = 36.64, SD = 9.09, mean experience = 6.53 years, SD = 3.31) completed the players’ and coaches’ surveys, respectively. Understanding women’s participation in and experiences of rugby is important to enable lifelong engagement and enjoyment of the sport and health during and following participation.

This paper investigates the human ability to perform rhythmic jumping on a vertically vibrating platform by analysing kinetics and kinematics. Ten test subjects participated, performing jumping on both non-vibrating and vibrating platforms. Vibration frequencies of 2.0, 2.4, and 2.8 Hz were used, with a vibration level of 2 m/s2. The frequency of jumping matched the vibration frequency, and for the first time, the jumps were timed relative to the platform’s position in the vibration cycle. A metronome prompted landings at four target positions: (i) reference position and on the way down (mid-down), (ii)lowest position (trough), (iii)reference position and on the way up (mid-up), and (iv)highest position (peak), at each frequency. The study compared the achievement of the target frequency of jumping between non-vibrating and vibrating platform conditions for each frequency. Results showed the worst performance when the target frequency was 2.8 Hz on the non-vibrating platform, confirming the difficulty of faster jumping on non-vibrating surfaces. The discrete relative phase analysis revealed a preference for landing at the trough and mid-up positions on the vibrating platform, particularly at 2.8 Hz. The preferred timing of jumps corresponded to greater toe clearance and impact ratio, but shorter contact duration compared to the non-vibrating platform. These findings hold promise for improving human-structure interaction models for assembly structures used in sports and musical events.

Research suggests that sensorimotor difficulties in autism could be reduced by providing individuals with explicit contextual information. To test this, we examined autistic visuomotor control during a virtual racquetball task, in which participants hit normal and unexpectedly-bouncy balls using a handheld controller. The probability of facing each type of ball was varied unpredictably over time. However, during cued trials, participants received explicit information about the likelihood of facing each uncertain outcome. When compared to neurotypical controls, autistic individuals displayed poorer task performance, atypical gaze profiles, and more restricted swing kinematics. These visuomotor patterns were not significantly affected by contextual cues, indicating that autistic people exhibit underlying differences in how prior information and environmental uncertainty are dynamically modulated during movement tasks.

PURPOSE: the potential impact of hormonal contraceptives (HCs) on player health and performance in women's rugby union (rugby) is not well understood, despite rugby's growing popularity worldwide. This study investigated the prevalence of HC use and reported associations with training and performance in a global sample of women rugby players. METHOD: a globally distributed online survey, seeking to explore experiences in women's rugby, was completed by 1596 current or former adult women 7s or 15s rugby players (mean age 27 [6] y; 7 [5] y playing experience) from 62 countries. The survey included a section of questions about reported HC use, including the type, reason for use, symptoms, and experiences relating to rugby training and performance. RESULTS: a total of 606 (38%) participants from 33 of the 62 (53%) countries reported using HCs, with the combined oral contraceptive pill reported as the most frequently used (44%). Almost half of participants using HCs (43%) tracked HC-related symptoms. Over 10% reported altered rugby performance due to HC-related symptoms, 22% required medication to manage symptoms, and 11% used HCs to control or stop their menstrual periods for rugby training and performance. CONCLUSIONS: the current study highlights the prevalence of HC use in women's rugby, identifying practices that may negatively affect performance, health, and well-being. Thus, there is an urgent need to better understand the motivations for such practices and knowledge of potential side effects among women rugby players across all levels and countries.

Background: Taking part in moderate-to-vigorous exercise in contact sports on a regular basis may be linked to an increase in cerebrovascular injury and head trauma. Validated objective measures are lacking in the initial post-event diagnosis of head injury. The exercise style, duration, and intensity may also confound diagnostic indicators. As a result, we propose that the new Interdisciplinary Group in Movement & Performance from Acute & Chronic Head Trauma (IMPACT) analyze a variety of functional (biomechanical and motor control) tests as well as related biochemistry to see how they are affected by contact in sports and head injury. The study’s goal will be to look into the performance and physiological changes in rugby players after a game for head trauma and injury. Methods: This one-of-a-kind study will use a randomized controlled trial (RCT) utilizing a sport participation group and a non-participation control group. Forty male rugby 7 s players will be recruited for the study and allocated randomly to the experimental groups. The intervention group will participate in three straight rugby matches during a local 7 s rugby event. At the pre-match baseline, demographic and anthropometric data will be collected. This will be followed by the pre-match baseline collection of biochemical, biomechanical, and cognitive-motor task data. After three consecutive matches, the same measures will be taken. During each match, a notational analysis will be undertaken to obtain contact information. All measurements will be taken again 24, 48, and 72 h after the third match. Discussion: When the number of games increases owing to weariness and/or stressful circumstances, we expect a decline in body movement, coordination, and cognitive-motor tasks. Changes in blood biochemistry are expected to correspond to changes in biomechanics and cognitive-motor processes. This research proposal will generate considerable, ecologically valid data on the occurrence of head trauma events under game conditions, as well as the influence of these events on the biological systems of the performers. This will lead to a greater understanding of how sports participants react to exercise-induced injuries. This study’s scope will have far-reaching ramifications for doctors, coaches, managers, scientists, and sports regulatory bodies concerned with the health and well-being of athletic populations at all levels of competition, including all genders and ages.

This study aimed to increase understanding of the biomechanics and dynamics of the upper limbs during the contact phase of the round-off (RO) performed using three techniques. Twenty female gymnasts performed six successful RO trials in each condition: parallel, T-shape and reverse. Kinetic and kinematic data were collected for each trial. All analyses focused on the contact phase for each hand. Continuous joint profiles examined the dynamics of these tasks as well as the kinetic sequencing. In each case, joint angles, angular velocity, moments and powers at the wrist and elbow joint were reported. Difference between the contact phases of the techniques was examined using a one-way ANOVA SPM. The T-shape technique demonstrated negative power at the wrist during contact; however, the elbow joint compensated with a significantly greater positive power generation during the propulsive phase, suggesting a more effective technique compared to the reduced powers of the reverse and parallel. The order of the peak joint powers during the contact phase, the reverse technique, demonstrated a proximal to distal sequence, in contrast to the distal to proximal for the other techniques. These findings highlight the task-specific coordinative structures during this closed chained action.

(1) Background: We aimed to compare gender differences in knee biomechanics and neuromuscular
characteristics, and to determine the relationships between lower limb muscle pre-activations
and knee biomechanics during a single leg drop landing, in order to identify riskier landing
patterns to prevent injury and intervene properly. (2) Methods: Descriptive laboratory cross-sectional
study on 38 healthy untrained subjects with low to moderate physical activity status. (3) Results:
During the initial-contact phase of landing, females demonstrated greater peak vertical
ground reaction force (GRF) normalized to body weight (49.12 ± 7.53 vs. 39.88 ± 5.69 N/kg; p < 0.001;
Hedge’s g = 1.37), peak knee anterior reaction force normalized to body weight (0.23 ± 0.04 vs. 0.17
± 0.05 N/kg; p < 0.001; Hedge’s g = 1.33), and decreased pre-activation of the semitendinosus (45.10
± 20.05% vs. 34.03 ± 12.05%; p = 0.04; Hedge’s g = 0.67). The final regression equation was peak knee
anterior reaction force = 0.024 + 0.025 (peak knee flexion moment) − 0.02 (semitendinosus-to-vastus
lateralis pre-activation ratio) + 0.003 (peak vertical GRF) (R2 = 0.576, p < 0.001). (4) Conclusions:
Overall, the data provided in this study support that a reduced semitendinosus-to-vastus lateralis
pre-activation ratio predicted an increase in knee anterior reaction force and potentially an increase
in ACL forces. Female non-athletes had gender-specific landing characteristics that may contribute
to ACL injury. Future studies are warranted to consider more possible predictors of non-contact
ACL injury.

Background: Maintaining a healthy gait into old age is key to preserving the quality of life and reducing the risk of falling. Nonlinear dynamic analyses (NDAs) are a promising method of identifying characteristics of people who are at risk of falling based on their movement patterns. However, there is a range of NDA measures reported in the literature. The aim of this review was to summarise the variety, characteristics and range of the nonlinear dynamic measurements used to distinguish the gait kinematics of healthy older adults and older adults at risk of falling. Methods: Medline Ovid and Web of Science databases were searched. Forty-six papers were included for full-text review. Data extracted included participant and study design characteristics, fall risk assessment tools, analytical protocols and key results. Results: Among all nonlinear dynamic measures, Lyapunov Exponent (LyE) was most common, followed by entropy and then Fouquet Multipliers (FMs) measures. LyE and Multiscale Entropy (MSE) measures distinguished between older and younger adults and fall-prone versus non-fall-prone older adults. FMs were a less sensitive measure for studying changes in older adults’ gait. Methodology and data analysis procedures for estimating nonlinear dynamic measures differed greatly between studies and are a potential source of variability in cross-study comparisons and in generating reference values. Conclusion: Future studies should develop a standard procedure to apply and estimate LyE and entropy to quantify gait characteristics. This will enable the development of reference values in estimating the risk of falling.

Postural control research has focused on standing balance experiments on platforms moving with relatively large amplitudes (0.1-0.2 m). This study investigated balance strategies while standing on a platform moving 4 mm in anterior-posterior direction with frequency scaled linearly from 0.4 to 6 Hz. Platform motion and kinematic and kinetic information for nine healthy participants were recorded using motion capture and force plate systems. Coordination between hip, knee and ankle joint torque, and centre of mass (COM) and centre of pressure (COP) motion was quantified by vector coding. Significant main effect of platform frequency for knee-ankle and COP-COM phase relationship was observed (p = 0.023, p = 0.016). At frequencies below 2.11 and 2.34 Hz, ankle strategy was recruited. With ankle strategy, in-phase COP-COM motion with COP dominancy occurred at frequencies below 2.19 and 2.23 Hz during scaling up and down, respectively. As platform frequency passed these values, COM dominated over COP which was followed by anti-phase knee-ankle torque, called a knee strategy, and anti-phase motion between the COP and COM that allowed COP to regain dominance over COM. Collectively, we reveal knee strategy as a new and relevant strategy in real-life settings, and transition between ankle and knee strategies that underpinned transition between COP-COM relative motion.

The integration of prior expectations, sensory information, and environmental volatility is proposed to be atypical in Autism Spectrum Disorder, yet few studies have tested these predictive processes in active movement tasks. To address this gap in the research, we used an immersive virtual-reality racquetball paradigm to explore how visual sampling behaviours and movement kinematics are adjusted in relation to unexpected, uncertain, and volatile changes in environmental statistics. We found that prior expectations concerning ball 'bounciness' affected sensorimotor control in both autistic and neurotypical participants, with all individuals using prediction-driven gaze strategies to track the virtual ball. However, autistic participants showed substantial differences in visuomotor behaviour when environmental conditions were more volatile. Specifically, uncertainty-related performance difficulties in these conditions were accompanied by atypical movement kinematics and visual sampling responses. Results support proposals that autistic people overestimate the volatility of sensory environments, and suggest that context-sensitive differences in active inference could explain a range of movement-related difficulties in autism.

Combining biomechanics and motor control, the aim of this study was to investigate the limit cycle dynamics during the high bar longswing across the UK elite gymnastics pathway age groupings. Senior, junior and development gymnasts (N = 30) performed three sets of eight consecutive longswings on the high bar. The centre of mass motion was examined through Poincaré plots and recurrence quantification analysis exploring the limit cycle dynamics of the longswing. Close to one-dimensional limit cycles were displayed for the senior (correlation dimension (CD) = 1.17 ± .08), junior (CD = 1.26 ± .08) and development gymnasts (CD = 1.33 ± .14). Senior elite gymnasts displayed increased recurrence characteristics in addition to longer longswing duration (p 

AbstractThe aim of this study was to identify motor control solutions associated with the ability to maintain handstand balance. Using a novel approach, we investigated the dynamical interactions between centre of pressure (CoP) and centre of mass (CoM) motion. A gymnastics cohort was divided into a ‘less skilled’ group, who held handstands for 4–6 s, and a ‘more skilled’ group, who held handstands in excess of 10 s. CoP–CoM causality was investigated in anterior–posterior (AP) and medio-lateral (ML) directions, in addition to time–space, time–frequency and Hurst Exponent (H) analyses. Lower AP CoP to CoM causal drive and lower H values (&gt; 0.6) indicated the more skilled gymnasts were less reliant on CoP mechanics to drive CoM motion. More skilled performance demonstrated greater adaptability through use of reactive, as opposed to anticipatory, control strategies. Skilled performers additionally exploited mechanical advantages in ML (e.g. a wider base of support), compared to the less skilled athletes. A multiple regression analysis revealed H and frequency domain measures to be better predictors of handstand balance duration than time–space domain measures. The study findings highlight the advantage of an adaptable motor control system with a directional profile, and provide new insight into the clear, measurable footprint of CoP on the dynamics of CoM.

We studied novice gymnasts (N = 25) learning to form the longswing movement coordination pattern. The focus was the emerging behavioural organisation of centre of mass (CM) dynamics and the relative phase of the bar-CM angular motion. Seven novices learned a complete longswing by the end of the study, 8 novices showed no improvement in proportion of circle completed, and the remainder produced modest but persistent increments of final swing height without achieving a full circle. The radial angular velocity generated in the free fall phase and the circle location of bar-CM relative phase progressively and predominantly predicted circle completion. Bar-CM relative phase produced a consistent qualitative relation within- and between-subjects characteristic of a collective variable with the bar leading the CM on the initial downward antiphase segment and the CM leading on the upward antiphase segment. The ratio of these phases was related by the last practice session to degree of circle completion. The findings showed strong individual differences in the effect of practice on the early steps of learning the movement coordination where the progressive emergence of the longswing circle is driven by exploiting the positive- and minimising the negative-influence of gravity on the bar-CM coordination dynamics (candidate collective variable).

This paper is Part II of a study of the effects of practice on young adult novice gymnasts learning the movement coordination pattern of the longswing. The focus was the early stage of learning a critical component of the longswing, namely: through joint motion to inject mechanical energy into the upswing segment effectively to complete the longswing circle. Twenty-five novice male gymnasts received expert instruction while practicing two sessions a week for 3 weeks between a pre- and a post-practice assessment test trial. Seven novices completed a full circle by the end of Test 4. Completion of the longswing was positively related to the angular velocity generated in the gravity driven free fall of the initial segment and the greater rate of energy input in the upward segment. A successful performance in terms of the emergent movement pattern requires coordination of the onset, rate and level of energy input to counterbalance the negative influence of gravity on the second half upwards segment. The development of the complete longswing through the emergence of the collective variable dynamics (Paper 1) and biomechanical energetics of the gymnast (Paper 2) informs coaches, scientists and clinicians regarding task decomposition and learning the longswing.

This study investigated overarm throwing technique at different developmental ages in children from the perspective of three distinct, though potentially complementary, approaches to motor skill acquisition. Children at 6, 10, and 14 years of age (N = 18), completed dominant overarm throws during which whole-body kinematic data were collected. Firstly, application of Newell's ([1985]. Coordination, control and skill. In Advances in Psychology (Vol. 27, pp. 295-317). North-Holland.) stages of learning identified three distinct age-related coupling modes between forward motion of the centre-of-mass (CoM) and the wrist, which demonstrated a greater range of couplings for older children. Secondly, in line with Bernstein's ([1967]. The coordination and regulation of movement. London: Pergamon Press.) hypothesis of freezing before freeing degrees of freedom, a significantly smaller range of motion (ROM) at the ankle and knee joints, but greater ROM at the hip and upper limb joints was found for the 6 year old group compared to the 10 and 14 year old groups. Thirdly, based on the components model (Roberton & Halverson [1984]. Developing children-their changing movement: a guide for teachers. Lea & Febiger.), the overarm throws demonstrated by 6 year olds were characterised as primitive to intermediate, where 10 and 14 year old's throws were characterised by the penultimate action level for each component. Characteristics of CoM-wrist coupling more clearly identify children's age-related technique and highlight the importance of posture-ball release dynamics. The posture-ball dynamics were supported by changes in ROM and the components model, revealing the complementary nature of the three approaches to the analysis of age-related differences in overarm throwing action.

A case study visualisation approach to examining the coordination and variability of multiple interacting segments is presented using a whole-body gymnastic skill as the task example. One elite male gymnast performed 10 trials of 10 longswings whilst three-dimensional locations of joint centres were tracked using a motion analysis system. Segment angles were used to define coupling between the arms and trunk, trunk and thighs and thighs and shanks. Rectified continuous relative phase profiles for each interacting couple for 80 longswings were produced. Graphical representations of coordination couplings are presented that include the traditional single coupling, followed by the relational dynamics of two couplings and finally three couplings simultaneously plotted. This method highlights the power of visualisation of movement dynamics and identifies properties of the global interacting segmental couplings that a more formal analysis may not reveal. Visualisation precedes and informs the appropriate qualitative and quantitative analysis of the dynamics.

Objectives: This review aims to: (1) map the use of sonification in human movement tasks for physical therapy; (2) identify methods of data capture, tasks and its effects on human subjects; (3) suggest future research directions. News: Sonification can be described as a technique to translate data into sound. It has been used for human motion analysis tasks even if it is not part of most physical therapist's lexicon. Prospects and projects: Identify and analyze publications where sonification was used as an audio-feedback technique for physical therapy. Thirty-five papers were included, 13 randomized-control-trials. Thirteen papers reported an investigation on a specific dysfunction, while upper limb movements were investigated in fifteen papers. Inertial measurement units were the most commonly used technology to capture human movement, 10 papers reported improvements in motor control and/or movement quality. Gaps in the literature were identified: (1) absence of sonification framework for rehabilitation, (2) no long-term comparison with gold-standard interventions for specific populations, (3) approaches for cardio-respiratory physical therapy and injury prevention were absent. Conclusion: Sonification has the potential to support rehabilitation for physical therapy. Effects of sonification were varied and ranged from improvements in movement quality/control, increased movement and body-awareness and improvements in performance when compared with activities with audio-visual or non-specific audio-feedback among others. Data for sonification was mainly captured using inertial measurement units, smartphones and optical tracking devices but others are also commonly used. Well-designed clinical trials supported by current promising results need to be developed. We recommend testing different sonification techniques in common physical therapy disfunctions using significant outcome measures to understand and maximize its effects on motor learning and control while scoping for further benefits.

Children with developmental coordination disorder (DCD) struggle with the acquisition of coordinated motor skills. This paper adopts a dynamical systems perspective to assess how individual coordination solutions might emerge following an intervention that trained accurate gaze control in a throw and catch task. Kinematic data were collected from six upper body sensors from twenty-one children with DCD, using a 3D motion analysis system, before and after a 4-week training intervention. Covariance matrices between kinematic measures were computed and distances between pairs of covariance matrices calculated using Riemannian geometry. Multidimensional scaling was then used to analyse differences between coordination patterns. The gaze trained group revealed significantly higher total coordination (sum of all the pairwise covariances) following training than a technique-trained control group. While the increase in total coordination also significantly predicted improvement in task performance, the distinct post-intervention coordination patterns for the gaze trained group were not consistent. Additionally, the gaze trained group revealed individual coordination patterns for successful catch attempts that were different from all the coordination patterns before training, whereas the control group did not. Taken together, the results of this interdisciplinary study illustrate how gaze training may encourage the emergence of coordination via self-organization in children with DCD.

Biomechanical research exploring the age-based mechanics of running gait can provide valuable insight into the reported decline in master endurance running performance. However, few studies have shown consistent biomechanical differences in the gait of trained distance runners compared to their younger counterparts. It might be that differences occur in the interaction between joints. The aim was to explore the differences in tri-joint synchrony of the lower limb, quantified through cluster phase analysis, of runners at 50 years of age compared to seven years later. Cluster phase analysis was used to examine changes in synchrony between 3 joints of the lower limb during the stance phase of running. Ten male, endurance-trained athletes M50 (age = 53.54 ± 2.56 years, mass = 71.05 ± 7.92 kg) participated in the study and returned after seven years M57 (age = 60.49 ± 2.56 years, mass = 69.08 ± 8.23 kg). Lower limb kinematics (Vicon, 120 Hz) and ground reaction forces (Kistler, 1080  Hz) were collected as participants performed multiple trials at a horizontal running velocity = 3.83 ± 0.40 m·s-1 over the force plate. Significant increase (31%) in rate of force development in the absorption phase, and significantly reduced sagittal plane knee joint range of motion (30.50 v 23.68°) were found following the seven years of ageing. No further discrete single joint measures were significantly different between M50 and M57. Joint synchrony between the hip, knee and ankle was significantly higher at M57 compared to M50 during the absorption phase of stance. The force attenuation strategy is compromised after seven years of ageing, which is associated with more synchronous movements in the lower limb joints. Increased joint synchrony as a function of age could be a mechanism associated with this key injury provoking phase of running gait.

Many important notions in Life Sciences are linked with the idea of cycles, periodicity, fluctuations and transitions. The aim of this paper is to use spectral analysis in a unique way to study and quantify whole body coordination during gait. A participant walked at 3 km/h and ran at 15 km/h on a treadmill for 2 minutes. Position of the approximate center of rotation of the toe, ankle, knee, hip, shoulder, elbow and wrist, heel, PSIS and head were collected (CODAmotion; 100 Hz). Fast Fourier Transform was performed on x-coordinate data of the 1) knee marker; 2) 4 markers attached to the free lower limb (toe, ankle, heel and knee); 3) left and right free lower limbs; 4) whole body (all markers). Gait is described by a largely harmonic and resonant oscillator that operates unilateral free limbs at the stride frequency, and axial regions at the step frequency. Running is described by a more harmonic and resonant oscillating structure than walking, with a 3 times higher Q factor and 47% lower Inharmonicity Index. This method is presented as a way to capture global dynamics of our complex multi-segment system, and presents a novel application of spectral analysis to study coordination.

The purpose of the study was to examine the macroscopic dynamics of the longswing through a limit cycle analysis of the motion of the center of mass (CM) as a function of skill level. One elite international, five gymnasts able to perform release and regrasp skills, five gymnasts unable to perform release and regrasp skills, and five novice gymnasts each performed four consecutive longswings on a high bar. Kinematic data were collected to facilitate the calculation of the center of mass position of the performer during swinging. Poincare plots were used to explore the limit cycle dynamics of the center of mass movement. The attractor dynamic was very close to a one-dimensional limit cycle for the elite (D = 1.18) but higher for the release and regrasp group (D = 1.35 ± 0.06) and non-release and regrasp group (D = 1.37 ± 0.07). The novice dynamic was characterized by a two-dimensional limit cycle (D = 2.49 ± 0.28) that also had more variability and lower determinism. In the frequency domain, Inharmonicity was lower and the Q factor higher as a function of increased skill level. The findings show that the dynamical degrees of freedom of the CM in the skilled performance were reduced compared to those of novices and represented a more efficient and predictive, rather than exploratory, technique.