A 6-week short foot exercise intervention enhances barefoot and shod vertical but not horizontal jump performance in team sports players

The foot muscles stiffen the metatarsophalangeal joint during the propulsive phase of jumping. This increases the external moment arm of the ground reaction force and increases plantar flexor force production (Smith et al., 2022) and may explain the increased vertical heights (Yamauchi & Koyama, 2020) and horizontal jump distances (Goldmann et al., 2013) associated with foot strength. Previous foot training interventions that improved jump performance mostly utilised specific toe flexor strengthening exercises. The short foot exercise (SFE) requires no equipment and involves raising the medial longitudinal arch by drawing in the metatarsal heads which target the intrinsic foot muscles (Gooding et al., 2016). Yet, the effect on jump performance is unknown. Moreover, previous foot training interventions have not considered the effect of footwear on jump performance. Footwear stiffness has been shown to enhance jump height (Lam et al., 2018), but may diminish the effect of stronger foot muscles.