The objective of this project is to directly measure rectus and biceps femoris muscle dynamics during a variety of tasks, like walking, running, and slips. The hip joint is critical for stabilizing walking through proper foot placement and is considered the “motor” of the legs. Thus, understanding how hip muscles produce and transfer energy across the limb can provide a roadmap for the design of assistive devices that work in concert with these major muscle groups to make walking more stable and less metabolically costly. To measure muscle dynamics our lab uses B-mode ultrasound in addition to the biomechanical toolkit of electromyography, motion capture, and musculoskeletal simulations.