The Activation Pattern of Trunk and Lower Limb Muscles in an Electromyographic Assessment; Comparison Between Ground and Treadmill Walking

BACKGROUND Due to biomechanical differences, various patterns of muscle contraction are expected to occur while walking over ground versus when walking on a treadmill. OBJECTIVES This study aimed to compare amplitude and duration of activation of selected trunk and lower extremity muscles during over-ground and treadmill walking. MATERIALS AND METHODS Through a simple sampling method, 19 sedentary healthy men within the age range of 20 - 40 were selected. Surface electromyography of rectus abdominis, external oblique, longissimus and multifidus muscles as the selected trunk muscles and vastus medialis, vastus lateralis and hamstrings as the selected lower limb muscles were recorded. RESULTS In each gait cycle, there were no statistically significant differences in duration of selected trunk as well as lower limb muscles activity between treadmill and over-ground walking. However the mean amplitude of rectus abdominis (P = 0.005), longissimus (P = 0.018) and multifidus (P = 0.044) as the selected trunk muscles as well as the mean amplitude of vastus lateralis (P = 0.005) and vastus medialis (P < 0.001) as the lower limb muscles was greater on treadmill compared with over ground. CONCLUSIONS Due to the stabilizing role of trunk and lower limb muscles during walking, these muscles seem to be active throughout the entire gait cycle. The increased muscle amplitude on treadmill can demonstrate that more motor units may be recruited during the contraction, which can be helpful in prescribing the appropriate type of exercise especially for patients with core muscle weakness.