Joint Moments and Powers in Healthy Young Adults During Stair Negotiation

The primary objective of this study was to determine lower limb joint moments and powers of stair negotiation in healthy young individuals. These results will provide baseline information for future studies with elderly and clinical populations designed to prevent falls that occur during stair negotiation. In previous stair negotiation studies, researchers investigated joint moments and powers initiating stair ascent in front of the stairway. Starting farther away from the stairway allows individuals to stabilize gait velocity and thus, exclude the influence of velocity on joint moments and powers generated during stair ascent. Ten young, healthy individuals underwent gait analysis during stair negotiation. Two way repeated measures ANOVA was used to determine the differences between two different conditions, starting farther away from the stairway (C1) and starting in front of the stairway (C2), for two consecutive steps (s1 and s2) on the stairway performed by the same leg. A motion analysis system was used to collect the three-dimensional spatial trajectories of the markers (joint angle data). Ground reaction forces were collected using two AMTI force platforms embedded in the first and the third stair treads. Our results demonstrated that ankle power absorption (PA1) was significantly higher during the s1 and s2 in C1 than during the s1 in C2. PA1 was significantly greater during s2 than during s1 in condition 2. Ankle power generation (PA2) was significantly higher during s2 than s1 in C1. The hip power absorption (PH2) was significantly higher during s1 in C1 than during s2 in C1, and s1 and s2 in C2. PH2 was significantly higher during s1 in C2 than s2 in both C1 and C2. These findings iv showed that the way individuals approach stairs will have a different affect on the ankle and the hip joints which has to be considered in future studies in stair negotiation