The Effect of Habitual Walking in Minimalist Footwear on Dynamic Balance and Lower Limb Strength

Recent evidence suggests that habitual walking in minimalist shoes leads to reductions in knee loading in osteoarthritic women (Shakoor et al. 2013), and increased muscular strength and flexion in the metatarsophalangeal joints (Potthast et al. 2005) compared to traditional shoes. Further understanding of the benefits of habitual walking in minimalist footwear within clinical populations is warranted to establish potential beneficial effects on a range of conditions. The purpose of this study was to examine the chronic effect of minimalist footwear on measures of dynamic balance and strength of lower limb musculature. Fifteen healthy adult males voluntarily participated in the study (age 30.4 ± 9.4 yr) and were assigned into an intervention (IG; n=7) or control group (CG; n=8). The IG performed an 8 wk accommodation period of wearing minimalist footwear (2.5 mm sole thickness; Feelmax Osma 2) for at least 6 h.d-1 for 5 d.wk-1. Dynamic balance was assessed bilaterally using the Y-Balance Test (YBT) in 3 directions (anterior, posteromedial and posterolateral). Maximum voluntary isokinetic strength was measured for ankle plantarflexion and dorsiflexion (Humac Norm).Leg length and height were significantly correlated to reach distance in the anterior direction in the YBT (p > 0.05); excursion distances were normalised to participant’s leg length (Gribble & Hertel, 2003). Post-test analysis revealed an increase in the YBT in all directions for both groups; however only the anterior excursion distance in the left leg for the IG (p = 0.003) and the right leg for the CG (p =0.007) were significant. The IG had an increase in maximal eccentric plantarflexion in the left foot (18%; p = 0.021; see Fig 1); there was also a non-significant increase in concentric plantarflexion strength in both the right (45.8%, p = 0.146) and left foot (21.6%, p = 0.116). No improvement in lower limb strength was observed in the CG. There was also an inverse relationship between the percentage change for the IG in left foot anterior excursion distance and right concentric dorsiflexion strength (r = -0.87; p = 0.025). The findings suggest that habitual walking in minimalist footwear resulted in functional improvements in lower limb strength, however this did not translate into consistent improvements in dynamic balance.