Force and Gait Mechanics at Reduced Body Weight on a Lower Body Positive Pressure Treadmill

Lower body positive pressure treadmills (LBPPT) have gained increasing attention due to their potential applications in sports training, rehabilitation, and biomechanics research. However, there is limited understanding of how differing body weight percentages influence gait and force production. This study aimed to investigate the relationship between force and gait parameters at different body weight percentages on a LBPPT. Twenty-seven healthy participants completed a series of walking, jogging, and running trials at three different body weight conditions: 100%, 90%, and 75%. Gait parameters, including cadence, stride length, stance time, and ground reaction force, were measured using the Digitsole Pro foot insoles and analyzed across the different conditions. Repeated measures ANOVA and pairwise comparisons were used to examine the effects of body weight percentage on the gait parameters. The results showed significant effects of BW on cadence, stride length, stance time, and impact force during running condition (p < 0.001). Jogging condition was significantly different across all % BW for all variables except ground reaction force (GRF). For walking, the only significant differences presented were for stride length on the right limb between 100% and 90% BW (p = 0.004) and 100% and 75% BW (p = 0.04) and time in stance on the left and right (p < 0.05). Pairwise comparisons revealed significant differences between the 100%, 90%, and 75% BW conditions for most gait parameters during jogging and running. These findings suggest that lower body weight percentages substantially influence gait mechanics and force production, especially as speed increases.