A shoe with random midsole deformations increases ankle joint variability and muscle activations during the forward lunge

摘要

Unstable shoes (USs) are designed to cause instability, which is suggested to elicit training benefits. However, studies of US are limited to standing, walking and running, and not all report increased muscle activations (Sacco et al. 2012; Stoggl, Haudum, Birklbauer, Murrer, & Miiller, 2010) and balance enhancements (Ramstrand, Thuesen, Nielsen, & Rusaw, 2010). Perhaps US may provide a greater training stimulus during more challenging dynamic movements, involving longer balancing phases. The forward lunge is a closed kinetic chain exercise, frequently utilized in exercise regimes that is applicable to daily life and sports. An US with random midsole deformations increases shank muscle activations and joint variability during walking and running, which according to dynamics systems theory would unlock the degrees of freedom and increase adaptability to perturbations (Apps et al., 2017). It was hypothesized that this shoe with irregular midsole (IM) would also increase instability during lunges.