This study examined loads imposed on the lumbar spine during walking at slow and fast speeds. EMG activity of lumbar spine muscles (erector spinae, rectus abdominus, and abdominal obliques) were monitored and correlated with a biomechanical model of loads on the lumbar spine developed by Albert Schultz, PhD (Spine, 6(1): 76-82, 1981) that incorporated 22 single muscle equivalents. EMG activity accurately predicted loads on the lumbar spine during walking at slow and fast speeds. Coefficients of linear correlation ranged between 0.71 to 1.00 for EMG activity as correlated with model predictions. An article from this Master's thesis was published in 1989 in the Journal of Orthopaedic Research, 7:371-377.