A Parameter to Describe Coordination of Hip and Knee Flexion during Obstructed Gait

During obstacle crossing, healthy adults increase toeground/obstacle clearance from an average of 3 cm during level walking to approximately 10-15 cm over an obstacle (Chen et al., 1991; Patla et al., 1996; Chou et al., 1997) to minimize the risk of tripping. The hip, knee and ankle joints of the swing limb are modulated for phase and amplitude of flexion to ensure appropriate elevation of the swing foot over the obstacle (Patla et al., 1996). Due to a different proximity of the swing foot at the time of toe-off with the location of the obstacle, strategies with emphasis on different joints are adopted to elevate the swing foot to clear the obstacle (McFayden and Winter, 1991; Patla et al., 1996; Chou et al., 1997). The purposes of this study was to define a parameter that could describe different coordination strategies of hip and knee flexion of the leading and trailing limbs during obstacle crossing and to examine its relationship with the obstacle height in healthy young adults.