Figure 1. Free-fall landing and related measurements. An example of single ground reaction force (GRF) data acquired from one load cell A); average GRF on bilateral hindfeet during 8 weeks of free-fall landing training B). Values are means ± SEM. *, significantly higher than the other time points, p < 0.05. GRF, ground reaction force, which was presented as folds of standing force (unit: N*N-1).