Speed Dependent Changes In Emg Patterns In Minimalistic Footwear; Effects Of Footstrike Pattern: Preliminary Results

To investigate speed dependent changes in EMG patterns during running in minimalistic footwear in relation to foot strike pattern. 6 competitive runners (42 + or - 10 years, 183.8 + or - 1.2 cm, and 75.4 + or - 8.1 kg), 3 of them were running with a RFS and 3 with a MFS/FFS, performed one minute trials at a treadmill at 6 different running speeds (10-15 km/h) while wearing minimal footwear. Smooth Rectified EMG (SRE) was filtered with a 3rd order low-pass filter with a cut-off frequency of 20 Hz. SRE was re-sampled to 100 HZ. Stance time decreased from 49 to 42% (mean 45.5 + or -2.6) of gait cycle in RFS and from 44 to 38% (mean 41 + or - 2.1) in MFS/FFS with increasing speed. For maximal amplitude, highest increases of 46% were found for the RF in the RFS condition and of 32% for ST and SL in the MFS/FFS condition.