Effects of obesity on the energetics/mechanics of slope walking. This study aims to determine whether walking slowly up an incline can be an effective means of achieving high rates of energy expenditure while reducing lower extremity joint loads (compared to brisk overground, level walking). We quantify lower extremity biomechanics during uphill/downhill walking via our new dual-belt, force measuring inclinable treadmill and motion capture system. As part of this study we are developing more accurate motion capture techniques and anthropometric models for obese and lean populations to better quantify the mechanics and energetics of gradient walking. We will use this data to develop musculoskeletal models to estimate contact forces to assist with specific exercise prescriptions for individuals with obesity. Our current results show that obese and non-obese employ different movement strategies when walking on level and uphill grades. There is an increase in joint flexion and hip extensor angular impulse as subjects walk up steeper grades with obese having larger values than non-obese. In early stance, non-obese trend toward having greater peak knee extensor moments which increase with grade, while obese have lower knee extensor moments which remain consistent across grades. There is a proximal shift in power production to the hip as the grade increase with this shift being greater in obese. When compared to non-obese, obese have more hip, less ankle, and similar knee joint work. The obese show less net joint work (J/kg) than non-obese with grade. However, at level walking, obese have greater net joint work with a similar metabolic rate. These results indicate a possible stratagem in obese to reduce knee loading and/or reduce metabolic cost/rate. Click on figure of the skeleton for a video.

Figure. 3. E gross and E net during treadmill walking in non-obese (open shapes) and obese adults (filled shapes). The average VO2, gross (A), E gross (B), mass-specific E gross (C), and mass-specific E net (D) plotted as a function of walking velocity.