University of Kassel, Institute for Sports and Sport Science, Kassel, Germany
Many open motor skills, for example in team sports and combat sports, are executed under mild to severe conditions of instability. Therefore, over the past two decades, coaching professionals and athletes have shown increasing interest in training routines to enhance the physical prerequisites for strength performance in this regard. Exercise scientists have identified instability resistance training as a possible means to improve strength performance under conditions of instability with a special emphasis on the core muscles. In this letter article, more specifically, we firstly argue that effects of resistance training may be found not only in the core muscles but in the stabilizer muscles in general. Moreover, specific testing procedures are needed to assess strength performance under instability as compared to stable testing. As a second issue of this letter article, we consider instability to be an inappropriate term to characterize mild to moderate equilibrium disturbances during competition and exercise. Instead, when conceptualizing the human body as a dynamic system, metastability appears to better suit the conditions of strength performance on slippery surfaces, waves, during gusts of wind or tackling opponents for example. In fact, this term is conventionally used to characterize other dynamic systems in thermodynamics, financial markets, climatology, and social groups for instance. In the recent past, metastability has been discussed for issues in motor control as well. Hence, we argue that metastability idea should be applied to exercise science as well when assigning the biomechanical equilibrium conditions during perturbed strength performance.
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