A, The start of the hip extension movement (dashed gray vertical line) was defined as the frame in which the frame displacement exceeded 0.04° and was maintained for 100 milliseconds. B, The raw electromyographic (EMG) data were rectified (thin black line) and low-pass filtered at 10 Hz (thick white line). The muscle onset (dashed gray vertical line) was defined as the point at which the EMG activity of the muscle exceeded the resting mean by 3 SDs (thick gray horizontal line) and maintained that activity for at least 75 milliseconds. Two repetitions of prone hip extension are displayed from a representative participant during the no-cues condition.