Edinburgh Napier University

  Human gait has been extensively investigated, althoughless is reported about trunk muscle activation during gait.The study aim was to determine internal oblique (IO) andexternal oblique (EO) muscle activity during walking andrunning, using a quartile method of analysis. Kinematicdata were collected using 10 high speed cameras toidentify reflective markers positioned over the left andright lateral malleoli in 12 healthy participants. Surfaceelectromyography (EMG) electrodes were attached to EOand IO (left and right sides). EMG signals were transmitted via telemetry and synchronised with the kinematic data collected during treadmill walk and run (three trials each). Surface EMG data were full-wave rectified and re-sampled to match kinematic data. Data were cut into motion cycles based on the right malleolus. From each motion cycle, the stride parameters of height and length based on the left and right malleoli were calculated. EMG data were expressed as a percentage of the Maximal Observed EMG (%MOE) and the first (Q1), second (Q2), third (Q3) and interquartile range (IQR) were calculated. For Q2 during walk, OI left was significantly greater than OE left (p=0.038), but no statistical significance between any muscles for Q2 was found during running. There were no statistically significant IQR differences found between any of the muscles duringwalking or running. In conclusion, OI and OE are similarin their phasic activity during walking and running.