Trunk flexion strategy and the loads in the lower limbs when walking up surfaces of different slopes

Walking inclined ground surfaces presents a number of challenges to the human locomotor system, especially for those with neuromusculoskeletal injuries or diseases. The purpose of the current study was to perform a complete 3D kinetics analysis of the locomotor system during uphill walking on surfaces of different inclinations in order to reveal interactions of the joints and the trunk motion, and the related mechanical demands for future clinical applications. Fifteen young adults were asked to walk on inclined sloped walkways with 0, 5, 10, 15 degrees of slopes while kinematic and kinetic data were collected and analyzed. The results showed that the subjects increased the anterior tilt of the pelvis and the flexion of the trunk with increased inclination angles, maintaining more or less constant moments at the ankle, but modulating the moments at the hip and knee during the first half of the stance phase, and the moments at the hip only during the second half of the stance phase. In response to weight acceptance and propulsion of the body's COM, differences in the peak inter-segmental joint resultant force magnitudes at different inclination angles occurred primarily in the anterioposterior direction for all the joints of the lower extremities. The angular extensor impulses at all the joints increased linearly with increased slope, suggesting an overall linear joint angular impulse control during uphill walking. The current data and findings may serve as baseline data for future clinical purposes and may be helpful for other ergonomic applications. ? 2012 National Taiwan University.