Comparison Of Intrinsic Foot Muscle Size And Strength Between Gymnasts And Shod Runners

Abstract

PURPOSE: Wearing supportive footwear during athletic activity may decrease the activity of the intrinsic foot muscles (IFM), leading to weaker muscles and suboptimal foot function. The purpose of this study was to compare the IFM size and strength of two athletic populations - gymnasts who train barefoot and runners who wear cushioned running shoes during training. METHODS: IFM size and toe flexor strength were measured from 13 female gymnasts (age: 19.8 ± .9 years; height: 158.9 ± 4.98 cm; weight: 56.9 ± 4.27 kg) and 21 female runners (age: 22.1 ± 2.95 years; height: 167.4 ± 8.88 cm; weight: 63.0 ± 9.38 kg). Strength was assessed from the big toe individually, and the 2nd, 3rd, and 4th toes together. During testing, the subject was seated with the knee flexed at 90°and the foot on the floor. The toes were aligned with a customized dynamometer. The subject gripped an S-beaner (great toe flexion) or a bar (lateral toe flexion) with their toe(s) and flexed to a maximal contraction for 3 seconds. The average of 3 trials was used for analysis. . Ultrasound images (10 MHz GE LogiqP6) were recorded of the abductor hallucis (ABDH), quadratus plantae (QP), flexor digitorum brevis (FDB) and flexor hallucis brevis (FHB). Measurements included the cross-sectional areas of the ABDH, QP, FDB and thickness of the FHB. ANCOVAs (with height and weight as covariates) were run to compare the IFM size and flexor strength between the groups of subjects. RESULTS: Gymnasts had larger FDB and FHB, as well as stronger great toe flexion than runners (see table). CONCLUSION: The IFM responsible for toe flexion and great toe flexion strength were greater in gymnasts than runners. Based on these data, training without cushioned footwear, in a task that requires finer control of the foot, has resulted in increased great toe flexion strength. Though it’s difficult to separate training task from footwear in this study, these findings lend support to the idea that training in cushioned footwear may hinder optimal IFM function.Table: No title available.