Investigating optimal technique in a noisy environment: Application to the upstart on uneven bars Michael J. Hiley ⇑ , Maurice R. Yeadon School of Sport, Exercise & Health Sciences, Loughborough University, Loughborough, UK article info Article history: Available online 23 December 2012 PsycINFO classification: 2330 Keywords: Simulation Optimization criterion Movement variability Gymnastics abstract The upstart is a fundamental skill in gymnastics where it 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 optimize the technique in the upstart on the uneven bars in order to determine the underlying con- trol strategy used by gymnasts. A previous attempt based on mini- mizing joint torque had failed to find a satisfactory solution without forcing the joint angle histories to pass through a ‘‘via- point’’ (Yamasaki, Gotoh, & Xin, 2010). Using a computer simulation model of a gymnast and bar, the technique (joint angle histories) used in the upstart was optimized under three different criteria: minimizing joint torque, minimizing joint torque change and maxi- mizing success in the presence of movement variability. The third optimization introduced ‘‘noise’’ into the joint angle time histories based on measurements of kinematic variability. All three optimiza- tions 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 his- tories were computed. The two optimizations based on minimizing joint torque diverged from the gymnast’s technique. However, the technique based on maximizing the number of successful perfor- mances 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 minimization 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. Ó 2012 Elsevier B.V. All rights reserved. 0167-9457/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.humov.2012.11.004 ⇑ Corresponding author. Tel.: +44 (0)1509 226373; fax: +44 (0)1509 226301. E-mail address: m.j.hiley@lboro.ac.uk (M.J. Hiley). Human Movement Science 32 (2013) 181–191 Contents lists available at SciVerse ScienceDirect Human Movement Science journal homepage: www.elsevier.com/locate/humov