The effect of minimalist shoe training on lower limb kinematics and kinetics

Previous literature has focused mainly on acute changes in minimalist shoe running. Thus, limited data exists on a transition process, warranting longitudinally designed studies. PURPOSE: To determine if lower limb running gait would be adapted and if impact force would be attenuated in response to a minimalist shoe transition programme. METHODS:Twenty-two healthy male endurance runners (age 24 ± 2.2 yrs; weekly mileage 27 ± 5.9 km) were randomly assigned into two groups: experimental (E) who underwent a seven-week Vibram Fivefingers Bikilas® (VF) training program; and control (C) who maintained usual shod training. Vicon® (eight cameras) motion capture system, synchronized with a Bertec® force plate, recorded lower limb running biomechanics. Twelve bilateral running trials from all participants were performed in the VF at pre- and post-tests respectively. Self-selected running speeds were monitored with timing gates at 3.5 m/s ± 10 % (within day) ± 1 % (between day). Parameters of interest were kinematic: step frequency (SF), strike index (SI), and sagittal plane knee footstrike angle (FSA); and kinetic: vertical impact force peak (VIP), vertical average loading rate 20-80 % of impact transient (VALR) and maximum vertical pushing peak (VPP). RESULTS:T-tests revealed no statistically significant pre-post changes between the E and C group for any kinematic or kinetic parameters of interest (p > 0.05). The E group did however show tendencies to decrease SI (shift towards rearfoot strike) (49 ± 25.5% to 40 ± 24.7%), increase knee FSA (17 ± 5.3 degrees to 19 ± 5.9 degrees), and increase SF (159 ± 9.9 steps/min to 161 ± 9.2 steps/min) from pre- to post. The E group also showed a non-significant trend to increase VIP by 10% (1.25 ± 0.3 BW to 1.38 ± 0.3 BW), increase VALR by 18% (54 ± 28.6 BW/s to 63 ± 31.8 BW/s), and maintain VPP at (2.4 ± 0.2 BW) from pre- to post. CONCLUSIONS:No statistically significant learning effect with regard to lower limb kinematic adaptation or kinetic impact force attenuation was observed after seven-weeks of VF training. This could be attributed either to an inability to sense higher impact while running in VF, or due to insufficient time permitted for kinematic habits to develop and/or musculoskeletal adaptation comparable to that of an experienced barefoot runner.status: publishe