Acute response to barefoot running in habitually shod males.

The aim of this study was to examine the immediate effects of barefoot (BF) running on lower limb kinematics and muscle activity in a group of habitually shod runners. Ten male runners with no prior BF or minimalist running experience performed 1-min bouts of treadmill running at 3 velocities in both shod and BF conditions. 2D video data were recorded in order to quantify ankle, knee and hip kinematics. Synchronous kinetic data were recorded from a force plate supporting the treadmill in order to quantify spatiotemporal variables. EMG data were collected from 6 lower limb muscles, quantifying recruitment patterns during discrete phases of the gait cycle. BF running resulted in significantly higher stride frequency and shorter ground contact times (P < .001). Additionally, BF running significantly reduced knee and hip range of motion but increased ankle range of motion during the absorptive phase of the stance. Alterations in ankle kinematics during BF running resulted from increased pre-activation of the medial (P < .05) and lateral (P < .01) gastrocnemius in addition to reductions in pre-activation of the tibialis anterior (P < .05). The results highlight that recruitment patterns and kinematics can change in as little as 30-s of BF running in individuals with no previous BF running experience.