Daily activity in minimal footwear increases foot strength

Abstract

The human foot is uniquely adapted to bipedal locomotion and has a deformable arch of variable stiffness. Intrinsic foot muscles regulate arch deformation, making them important for foot function. In this study we explore the hypothesis that normal daily activity in minimal footwear, which provides little or no support, increases foot muscle strength. Western adults wore minimal footwear for a six-month period (the “intervention” group). Foot strength, i.e., maximum isometric plantarflexion strength at the metatarsophalangeal joints, and foot biometrics were measured before and after the intervention. An additional group was investigated to add further insight on the long-term effects of footwear, consisting of Western adults with an average 2.5 years of experience in minimal footwear (the “experienced” group). This study shows that foot strength increases by, on average, 57.4% (p < 0.001) after six months of daily activity in minimal footwear. The experienced group had similar foot strength as the post intervention group, suggesting that six months of regular minimal footwear use is sufficient to gain full strength, which may aid healthy balance and gait.

The Effects of Minimalist Shoes on Plantar Intrinsic Foot Muscle Size and Strength: A Systematic Review

“…The four studies that assessed toe flexion strength used three different custom dynamometers 1 30 31 35 . Quinlan et al (2022) did not find a correlation between muscle size (CSA) and strength (hand-held dynamometer) in children, which opposes findings in adult populations 35 .…”

“…Some studies have demonstrated that habitually barefoot individuals have fewer foot and toe deformities and defects [27] as well as higher arch heights [28,29] compared to conventionally shod runners. Similarly, some individual studies have reported statistically significant improvements in IFM strength [1,30,31] and size [14,17,31,32] due to the usage of minimalist shoes. However, a systematic review to understand these changes in IFM strength or size has not yet been performed.…”

“…All 9 articles were assessed with the PEDro scale. Six of the studies were considered good with PEDro scores ranging from 6-7 [1,14,16,17,31,35], and 3 studies were considered fair with PEDro scores ranging from 4-5 [30,36].…”

“…One study used means of individual percent changes within each group [30], while all other studies compared group means before and after the intervention. Seven of the studies had statistically significant changes in muscle strength and size [1,14,16,17,[30][31][32], though consistent changes in size were not found in the same muscles across the included studies.…”

“…One study investigated children ages 9-12 [35]. Five of the studies recruited recreational or experienced runners who were habitually shod [14,16,17,30,31] with specific requirements in the amount to run or walk per week, as detailed in ▶ table 3. The studies used different training programs or protocols to transition into minimalist shoes.…”