Consistency of performances in the Tkatchev release and re-grasp on high bar

Fifty years of performance-related sports biomechanics research

Over the past fifty years there has been considerable development in motion analysis systems and in computer simulation modelling of sports movements while the relevance and importance of functional variability of sports technique has become increasingly recognised. Technical developments for experimental work have led to increased, and still increasing, subject numbers. Increased subjects per study give better statistical power, the ability to utilise different data analyses, and thus the determination of more subtle and nuanced factors. The overall number of studies has also increased massively. Most actions in sport can, and have, been studied at some level with even the more challenging ones, such as player on player impacts, having some developing research. Computer simulation models of sports movements have ranged from simple (one or two segment) models to very complex musculoskeletal models and have used parameters ranging from the generic to individual-specific. Simple models have given insights into the key mechanics of movement while individual-specific model optimisations have been used to improve athlete performance. Our depth of understanding of the mechanics of sports techniques has increased across a wide range of sports. In the future there is likely to be more development and use of markerless motion capture, individual-specific model parameters, and more consideration of motor control aspects in the analysis of sports technique.

Current issues and future directions in gymnastics research: biomechanics, motor control and coaching interface

The sport of gymnastics is undergoing a global examination of its culture and the relationship between the gymnast, coach and environment is a central focus. The aim of this review is to explore biomechanics and motor control research in skill development and technique selection in artistic gymnastics with a focus on the underlying concepts and scientific principles that allow performance enhancement, skill development and injury risk reduction. The current review examines peer reviewed papers from 2000 onwards, with a focus on contemporary approaches in the field of gymnastics research, and highlights several key directions for future gymnastics research. Based on our review and the integration of the models of Newell (1986) and Irwin et al. (2005), we recommend that future gymnastics research should embrace at the very least a multidisciplinary approach and aim for an interdisciplinary paradigm.

A Review of Forward-Dynamics Simulation Models for Predicting Optimal Technique in Maximal Effort Sporting Movements

The identification of optimum technique for maximal effort sporting tasks is one of the greatest challenges within sports biomechanics. A theoretical approach using forward-dynamics simulation allows individual parameters to be systematically perturbed independently of potentially confounding variables. Each study typically follows a four-stage process of model construction, parameter determination, model evaluation, and model optimization. This review critically evaluates forward-dynamics simulation models of maximal effort sporting movements using a dynamical systems theory framework. Organismic, environmental, and task constraints applied within such models are critically evaluated, and recommendations are made regarding future directions and best practices. The incorporation of self-organizational processes representing movement variability and “intrinsic dynamics” remains limited. In the future, forward-dynamics simulation models predicting individual-specific optimal techniques of sporting movements may be used as indicative rather than prescriptive tools within a coaching framework to aid applied practice and understanding, although researchers and practitioners should continue to consider concerns resulting from dynamical systems theory regarding the complexity of models and particularly regarding self-organization processes.

Identification of the contribution of contact and aerial biomechanical parameters in acrobatic performance

INTRODUCTION

Teaching acrobatic skills with a minimal amount of repetition is a major challenge for coaches. Biomechanical, statistical or computer simulation tools can help them identify the most determinant factors of performance. Release parameters, change in moment of inertia and segmental momentum transfers were identified in the prediction of acrobatics success. The purpose of the present study was to evaluate the relative contribution of these parameters in performance throughout expertise or optimisation based improvements. The counter movement forward in flight (CMFIF) was chosen for its intrinsic dichotomy between the accessibility of its attempt and complexity of its mastery.

METHODS

Three repetitions of the CMFIF performed by eight novice and eight advanced female gymnasts were recorded using a motion capture system. Optimal aerial techniques that maximise rotation potential at regrasp were also computed. A 14-segment-multibody-model defined through the Rigid Body Dynamics Library was used to compute recorded and optimal kinematics, and biomechanical parameters. A stepwise multiple linear regression was used to determine the relative contribution of these parameters in novice recorded, novice optimised, advanced recorded and advanced optimised trials. Finally, fixed effects of expertise and optimisation were tested through a mixed-effects analysis.

RESULTS AND DISCUSSION

Variation in release state only contributed to performances in novice recorded trials. Moment of inertia contribution to performance increased from novice recorded, to novice optimised, advanced recorded, and advanced optimised trials. Contribution to performance of momentum transfer to the trunk during the flight prevailed in all recorded trials. Although optimisation decreased transfer contribution, momentum transfer to the arms appeared.

CONCLUSION

Findings suggest that novices should be coached on both contact and aerial technique. Inversely, mainly improved aerial technique helped advanced gymnasts increase their performance. For both, reduction of the moment of inertia should be focused on. The method proposed in this article could be generalized to any aerial skill learning investigation.

What governs successful performance of a complex whole body movement: The Kovacs release-regrasp on horizontal bar?

The Kovacs is a release and regrasp skill performed on the horizontal bar in men׳s artistic gymnastics. It is a popular skill in elite competitive gymnastics with over 40% of male gymnasts performing a variation of the Kovacs at the London 2012 Olympics. In the qualifying competition 84% of Kovacs were successfully regrasped, with the remaining 16% resulting in a fall. The aim of the present study was to determine why some gymnasts are more successful than others at regrasping the bar, with a secondary aim to determine how a less successful gymnast could alter his technique in order to become more successful. Nine performances of the Kovacs by each of two gymnasts, one 100% successful and one 11% successful, were analysed to determine differences in release and regrasp parameters. The technique of the less successful gymnast was optimised using a computer simulation model to increase the percentage of catches (success rate). The successful gymnast had larger and more consistent release windows and a radial velocity towards the bar at regrasp. The less successful gymnast had higher horizontal velocity at release and a mean radial velocity away from the bar at regrasp. Optimising his simulated technique increased the rate of success from 11% to 93%. The actions prior to release were performed earlier than in the recorded performances leading to a more vertical path of the mass centre at release and a radial velocity towards the bar at regrasp.

Effect of hip flexibility on optimal stalder performances on high bar

In the optimisation of sports movements using computer simulation models, the joint actuators must be constrained in order to obtain realistic results. In models of a gymnast, the main constraint used in previous studies was maximum voluntary active joint torque. In the stalder, gymnasts reach their maximal hip flexion under the bar. The purpose of this study was to introduce a model of passive torque to assess the effect of the gymnast's flexibility on the technique of the straddled stalder. A three-dimensional kinematics driven simulation model was developed. The kinematics of the shoulder flexion, hip flexion and hip abduction were optimised to minimise torques for four hip flexion flexibilities: 100 degrees, 110 degrees, 120 degrees and 130 degrees. With decreased flexibility, the piked posture period is shorter and occurs later. Moreover the peaks of shoulder and hip torques increase. Gymnasts with low hip flexibility need to be stronger to achieve a stalder; hip flexibility should be considered by coaches before teaching this skill.