Background: Ankle osteoarthritis has been associated with trauma, instability, and inflammatory arthritis. Limited literature exists examining the effect of body weight on ankle joint loading. The purpose of this study was to examine the relationship between increased weight and gender on ankle kinematics and kinetics.
Methods: Fifty-three (28 male, 25 female) subjects were recruited for the study. All subjects underwent a standard level walking gait analysis in four different weight conditions (normal, 10%, 15%, and 20% increased body weight). Testing order was randomized. A series of mixed-factor, repeated-measures analyses of variance (weight by gender) were used to determine statistical differences between the groups (p < .05).
Results: Walking speed was not significantly different between gender or weight conditions. No significant differences existed for step length, step time, stride length, swing time, or sagittal plane ankle kinematics and kinetics. A significant increase in plantarflexion moment existed for the males (p < .05). The peak plantarflexion moment increased as weight increased. Single support time (p = .042) was significantly different between the no weight and the 15% and 20% increased weight conditions. In addition, double support time was significantly longer in the males compared with females (p < .001) and significantly increased for each weight condition (p < .001).
Conclusion: Increasing weight alters spatial temporal mechanics and sagittal plane ankle kinetics in a healthy control population. The effect of increasing weight appears to be similar between genders.
Clinical relevance: The findings of the present study may be relevant for future studies to assess the role of weight as a potential covariate on postoperative outcomes and gait mechanics.