Increased Hip-Flexion Gait as an Exercise Modality for the Reduction of Knee Joint Contact Forces: A Preliminary Investigation

Background: Increased hip-flexion gait (HFgait) has been shown to promote increased aerobic demands by increasing peak swing-phase hip-flexion angles while walking at comfortable speeds. Biomechanically, HFgait produces a gait pattern similar to walking, while removing the flight phase from running and reducing tibial accelerations. We sought to identify knee joint contact forces between HFgait and common exercise modalities, including running, walking, and cycling, across intensity levels. Methods: Ten healthy participants completed two bouts (low and high intensity) of four different exercises: treadmill running, walking, HFgait, and cycling. Tibiofemoral joint compressive force (TCF) was estimated using a static optimization-based approach. Results: Peak TCF was greater in running compared to HFgait, walking, and cycling; greater in HFgait compared to cycling; and greater in walking compared to cycling. The integral of TCF (iTCF) was greater in running compared to cycling, greater in HFgait compared to running, walking, and cycling, and greater in walking compared to running and cycling. Conclusions: HFgait produced lower knee joint loading than running, comparable joint loading to walking, and greater joint loading than cycling. Thus, HFgait may serve as an exercise modality for populations where joint loading is of particular concern, while achieving aerobic demands similar to running or increased functional demands compared to stationary cycling.