Genevieve Williams

Kinematic changes during learning the longswing on high bar

The purpose of this study is to provide evidence of technique changes during learning a sports-specific skill, the looped bar longswing (LLS). Thirteen male participants with no previous high bar experience took part in a training study. Kinematic data were collected using a CODA motion analysis system (200 Hz) during eight weekly testing sessions. Analyses focused on the amplitude of swing and the functional phase (FP) actions, defined by the rapid flexion to extension of the shoulders and extension to flexion of the hips as the performer passed through the lower vertical. Three groups were identified based on the number of sessions it took each participant to perform the LLS (G1: most successful, G2: intermediate, and G3: least successful). All participants were able to significantly increase swing amplitude over the training period (p < 0.05). For each participant the hip FP started significantly: later for G1, earlier for G2, and did not change for G3. Extension actions at the shoulders were dissimilar to those reported for elite gymnasts performing the longswing. The FP of the hips provides a mechanism to distinguish between the learners of different skill levels. The study has provided support for a single-subject design when investigating technique changes during learning.

Coordination as a function of skill level in the gymnastics longswing

Abstract The purpose of this study was to investigate the nature of inter-joint coordination at different levels of skilled performance to: (1) distinguish learners who were successful versus unsuccessful in terms of their task performance; (2) investigate the pathways of change during the learning of a new coordination pattern and (3) examine how the learner’s coordination patterns relate to those of experts in the longswing gymnastics skill. Continuous relative phase of hip and shoulder joint motions was examined for longswings performed by two groups of novices, successful (n = 4) and unsuccessful (n = 4) over five practice sessions, and two expert gymnasts. Principal component analysis showed that during longswing positions where least continuous relative phase variability occurred for expert gymnasts, high variability distinguished the successful from the unsuccessful novice group. Continuous relative phase profiles of successful novices became more out-of-phase over practice and less similar to the closely in-phase coupling of the expert gymnasts. Collectively, the findings support the proposition that at the level in inter-joint coordination a technique emerges that facilitates successful performance but is not more like an expert’s movement coordination. This finding questions the appropriateness of inferring development towards a “gold champion” movement coordination.

Biomechanical energetic analysis of technique during learning the longswing on the high bar

Abstract Biomechanical energetic analysis of technique can be performed to identify limits or constraints to performance outcome at the level of joint work, and to assess the mechanical efficiency of techniques. The aim of this study was to investigate the biomechanical energetic processes during learning the longswing on the high bar. Twelve male, novice participants took part in a training study. Kinematic and kinetics data were collected during swing attempts in eight weekly testing sessions. Inverse dynamics analysis was performed from known zero forces at the toes. Joint work, total energy, and bar energy were calculated. Biomechanical constraints to action, that is, limits to novice performance, were identified as “total work” and “shoulder work”. The most biomechanically efficient technique was associated with an onset of the hip functional phase and joint work that occurred between 10–45° before the bottom of the swing. The learning of gross motor skills is realised through the establishment of a set of techniques with task specific biomechanical constraints. Knowledge of the biomechanical constraints to action associated with more effective and efficient techniques will be useful for both assessing learning and establishing effective learning interventions.

Changes in joint kinetics during learning the longswing on high bar

Abstract Biomechanics helps us understand the association between technique changes and performance improvement during learning. The aim of this research was to investigate joint kinetic characteristics of technique during learning of the longswing on the high bar. Twelve male, novice participants took part in the learning study. During swing attempts in 8 weekly testing sessions, kinematic data were collected. Inverse dynamics analysis was performed from known zero forces at the toes to quantify joint moments and power at the hips and shoulders. Key biomechanical constraints that limited performance outcome were identified based on changes in joint kinetics during learning. These constraints were the ability to perform a large shoulder power and to overcome passive kinetics acting during the downswing. Constraints to action at the level of joint kinetics differentially challenge learners and therefore could underpin more individual, specific learning interventions. Functional phases, defined by maximum hyperextension to flexion of the hips and maximum flexion to extension of the shoulders, did not describe the key joint kinetics of the hip and shoulder for novices. The functional phases may serve however to identify novices that were unable to overcome the passive kinetic constraint.

Coordination in gait: Demonstration of a spectral approach

ABSTRACT 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.

Correlates of children's independent outdoor play: Cross-sectional analyses from the Millennium Cohort Study

Time spent outdoors is associated with higher levels of physical activity. To date, correlates of independent outdoor play have not been investigated. This study aimed to identify potential demographic, behavioural, environmental and social correlates of childrens independent outdoor play. Data were from the Millennium Cohort Study when children were aged 7 years. Parents reported whether their children played out unsupervised (yes/no) as well as the above mentioned correlates of unsupervised outdoor play. Childrens physical activity levels were measured using waist worn accelerometry. Multiple logistic regression was used to examine associations between correlates and odds of independent (unsupervised) outdoor play. Adjusted multiple linear regression was used to estimate associations between independent outdoor play and objective measures of physical activity. Activity was measured as average daily moderate-to-vigorous activity, steps, and sedentary behaviour. 3856 (n = 29%) participants were categorised as engaging in independent outdoor play. Older age, being white British, being in poverty, living in close proximity to both family friends and family, having fewer internalising problems, having more externalising conduct problems and fewer pro-social behaviours were associated with higher odds of independent outdoor play. Independent outdoor play was associated with > 2 additional minutes of moderate-to-vigorous activity (B = 2.21 95% CI, 1.09 to 3.34), > 330 additional steps per day (B = 336.66 95% CI 209.80 to 463.51), and nearly 5 min less time spent sedentary per day (B = − 4.91 95% CI − 7.54, − 2.29) Younger children, those from a higher socio-economic-status, those isolated in location from family friends and family, and those with high levels of prosocial behaviour have lower levels of independent outdoor play. Independent outdoor play was associated with higher levels of physical activity and less time sedentary. Future interventions to promote independent outdoor play should target such populations.

Multidimensional joint coupling: a case study visualisation approach to movement coordination and variability

Abstract 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.

Qualitative and quantitative change in the kinematics of learning a non-dominant overarm throw

This study investigated changes in non-dominant overarm throw technique over practice from the perspective of three distinct though potentially complementary approaches to motor skill acquisition. Ten participants (mean ± SD age 22 ± 2 yrs, stature 1.71 ± 0.60 m, mass 73 ± 14 kg) completed 9-practice sessions (each 10 trials), during which whole-body kinematic data were collected. In line with the motor learning model of Newell (1985), we examined changes in the coupling between the centre-of-mass (CoM) and wrist motion. During initial practice, coupling was initially in-phase moving to wrist-led coupling with whole-body motion. With practice a more complex backwards wrist-led coupling that progressed to forward wrist-led coupling was observed. Secondly, in line with Bernsteins (1967) notion of freezing before freeing degrees of freedom; a significant increase in joint angle range of motion (ROM) at the lower limb joints and shoulder, and significant decrease in elbow and wrist ROM was observed. Thirdly, ROM changes coincided with the time course of changes in the four components of technique change in overarm throwing action proposed by Robertson and Halverson (1984). Participants began in mid to high action levels for the torso/arm components, while the step component progressed to higher action levels with practice. Common practice induced changes in the collective posture-ball release dynamics and were supported by individual strategies at the joint ROM level revealing the complementarity nature of the three approaches and their key dependent variables to the analysis of learning to throw.

Limit cycle dynamics of the gymnastics longswing

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.

Prospective associations between measures of gross and fine motor coordination in infants and objectively measured physical activity and sedentary behavior in childhood

Abstract One important determinant of childhood physical activity and sedentary behavior may be that of motor development in infancy. The present analyses aimed to investigate whether gross and fine motor delays in infants were associated with objective and self-reported activity in childhood. Data were from the UK Millennium Cohort Study, a prospective cohort study, involving UK children born on or around the millennium (September 2000 and January 2002). When children were 9 months old, parents reported childrens fine and gross motor-coordination, and at 7 years, sports club attendance and daily TV viewing time. Childrens physical activity was measured using accelerometers at 7 years. Adjusted regression models were used to examine associations between delayed motor development and accelerometry measured moderate-to-vigorous physical activity and sedentary behavior, and parent-reported sport club attendance and TV viewing time. In this sample (n = 13,021), gross motor delay in infancy was associated with less time in moderate-to-vigorous physical activity (B −5.0 95% confidence interval [CI] −6.8, −3.2) and more time sedentary (B 13.5 95% CI 9.3, 17.8) in childhood. Gross and fine motor delays during infancy were associated with a reduced risk of having high attendance at sports clubs in childhood (both relative risk [RR] 0.7, 95% CI 0.6, 0.9). Fine motor delays, but not gross delays, were also associated with an increased risk of having high TV viewing time (RR 1.3 95% CI 1.0, 1.6). Findings from the present study suggest that delays in motor development in infancy are associated with physical activity and sedentary time in childhood.