Surface EMGs
After standard skin preparation, surface EMGs were used to record lower extremity and/or trunk muscles, depending on the task being tested. Muscles assessed for mapping and voluntary movement testing included bilateral vastus medialis, rectus femoris, tibialis anterior, hamstring, medial gastrocnemius, and gluteus medius. Muscles assessed for voluntary trunk and hip extension in semi-standing included bilateral medial hamstrings, vastus lateralis, gluteus medius, transverse abdominis, erector spinae at the level of the T10 vertebrae, and erector spinae at the level of the T5 vertebrae. All EMGs were collected at a 2000 Hz sampling rate using LabChart 8.1.21 (Windows)- ADInstruments. EMGs show in figures are rectified with a 10–990 Hz bandpass filter. In some instances, a root-mean-square filter was layered overtop of the original filtering with a 100-sample window.