Nonlinear Effects of Body Weight on Ground Reaction Force Peaks: Implications for Normalization

Ground reaction force (GRF) measurements are commonly reported in bodyweight (BW) units. Division normalization of this type reduces the contribution of body size differences to the variance among subjects. Several researchers have noted that peak force measurements can remain significantly correlated with BW, even after normalization. Most recently, Wannop et al. [1] examined GRF components and inverse dynamic parameters in both walking and running and found multiple examples of statistically significant non-linear scaling with BW. In many cases, normalization using offsets and power curves more effectively removed correlations with BW than simple division.