Modifications in lower leg muscle activation when walking barefoot or in minimalist shoes across different age-groups

Ageing is associated with a decline in muscle strength and impaired sensory mechanisms which contribute to an increased risk of falls. Walking barefooted has been suggested to promote increased muscle strength and improved proprioceptive sensibility through better activation of foot and ankle musculature. Minimalist footwear has been marketed as a method of reaping the suggested benefits of barefoot walking whilst still providing a protective surface. The aim of this study was to investigate if walking barefoot or in minimalist footwear provokes increased muscle activation compared to walking in conventional footwear. Seventy healthy adults (age range 20-87) volunteered for this study. All participants walked along a 7m walking lane five times in four different footwear conditions (barefoot (BF), minimalist shoes (MSH), their own shoes (SH) and control shoes (CON)). Muscle activity of their tibialis anterior (TA), gastrocnemius medialis (GCM) and peroneus longus (PL) were recorded simultaneously and normalised to the BF condition. MSH are intermediate in terms of ankle kinematics and muscle activation patterns. Walking BF or in MSH results in a decrease in TA activity at initial stance due to a flatter foot at contact in comparison to conventional footwear. Walking BF reduces PL activity at initial stance in the young and middle age but not the old. Walking in supportive footwear appears to reduce the balance modulation role of the GCM in the young and middle age but not the old, possibly as a result of slower walking speed when BF.