Investigating optimal technique in a noisy environment: Application to the upstart on uneven bars

Abstract

Additional Information:• NOTICE: this is the author's version of a work that was accepted for publication in Human Movement Science.Changes ABSTRACTThe upstart is a fundamental skill in gymnastics which is used to transfer a gymnast from a swing beneath the bar to a position above the bar. The aim of this study was to optimise the technique in the upstart on the uneven bars in order to determine the underlying control strategy used by gymnasts. A previous attempt based on minimising joint torque had failed to find a satisfactory solution without forcing the joint angle histories to pass through a "via-point" (Yamasaki et al., 2010). Using a computer simulation model of a gymnast and bar, the technique (joint angle histories) used in the upstart was optimised under three different criteria: minimising joint torque, minimising joint torque change and maximising success in the presence of movement variability. The third optimisation introduced "noise" into the joint angle time histories based on measurements of kinematic variability. All three optimisations were started from the technique used by a gymnast competing in an Olympic Games uneven bars final. Root mean squared (RMS) differences between the recorded and optimal joint angle time histories were computed. The two optimisations based on minimising joint torque diverged from the gymnast's technique. However, the technique based on maximising the number of successful performances in a noisy environment remained close to the gymnast's technique. It is concluded that the underlying strategy used in the upstart is not based on minimisation of joint torque; rather, it is based on ensuring success in the task despite the inherent variability in technique. Gymnasts develop techniques that are able to cope with the level of kinematic variability present in their movements.

Determining the Solution Space for a Coordinated Whole Body Movement in a Noisy Environment: Application to the Upstart in Gymnastics

“…18 Thus as gymnasts learn new skills they will develop techniques that are better able to cope with the level of noise resulting from the motor system. 1,4,27 An indication of the tolerance and covariation of the optimal upstart technique can be inferred from the regions of the contour plots associated with an acceptable success rate (Figure 6 and 7). Typically an elite gymnast would expect to have success rates in excess of 90% before including a skill within a competitive routine.…”

“…The study of Yamasaki et al 3 has since been repeated 1 , but with an extra criterion based on maximising success at the task whilst operating in a noisy environment. 4 The optimisation added noise to the joint angle time histories based on measures of human movement variability 5 which were used to represent movement execution noise resulting from the motor system.…”

The cross on rings performed by an Olympic champion

“…Low variability on forces means that a controlled skill is performed 26 . Because the cross is a closed skill, well learned and performed by experts, it is reasonable to assume a stable movement pattern would exist 27 . Asymmetry scores were used to analyse performance in sprint running 28 and to allow for asymmetry comparisons between athletes over time and between asymmetry and performance 21 .…”

Advances in the development of whole body computer simulation modelling of sports technique

“…In the field of sport effort is often maximised in order to achieve the performance outcome (Hiley, 2012). Movements that are heavily constrained by the mechanics of the movement and the strength and coordination ability of the gymnast may be effectively defined by these constraints rather than by any optimisation criterion (Hiley and Yeadon, 2013). Models employing sophisticated control algorithms to generate movement undoubtedly have a role in the study of the motor control and motor learning of sports movements.…”