Gender difference in gait during transition from level to stair descent in healthy older adults

Stair descent is associated with high incidence of falls and associated injuries, especially in older adults. Older women have shown greater risk of fall as compared to men and show greater hesitation during upper transition. However, there is no quantitative evidence to explain this gender difference. Therefore, the purpose of this dissertation is to investigate gender differences in gait of older adults during stair descent transitions. A total of 28 participants (12 male and 16 female; 68.5 years and 69 years respectively) performed stair descent in a step-over-step manner at a self-selected speed over a custom made three-step staircase with embedded force plates. The kinetic comparison during the stair descent transition shows that women exert higher frontal plane hip moments (-1.0 Nm/kg) and extensor moment and eccentric power (0.74 Nm/kg and 3.15 W/kg) on the trail leg knee joint as compared to men (-0.82 Nm/kg, 0.89 Nm/kg, 3.83 W/kg, respectively). Women also exerted lower eccentric power at the knee joint of the lead leg as compared to men. Analysis of angular momentum of the body about the stance foot revealed that women show greater change in angular momentum across the staircase as compared to men (0.92 Nms/ kgm and 0.45 Nms/ kgm, respectively). Women showed greater changes in angular momentum during double support phase primarily because of increased ground reaction force (GRF). Changes in angular momentum also showed that maximum control of angular momentum occurred during Step 0. These changes in angular momentum, signifying decreased stability, along with decreased knee control may explain increased risk of fall during stair descent in older women. Increased dependence on GRF to control the forward angular momentum provides quantitative evidence that women show hesitation during stair descent transition.