RELATIONSHIP OF GROUND AND KNEE JOINT REACTION FORCES IN PLYOMETRIC EXERCISES

Abstract

The purpose of the current study was to assess the relationship between peak vertical ground reaction force (GRF) and peak knee joint reaction force (KJRF). Eighteen recreationally active college students performed a countermovement jump, single leg jump, and drop jump from a height equal to their vertical jump. Vertical ground reaction forces were assessed with a force plate and KJRF were assessed using a combination of GRF and video data. A Paired samples t-Test revealed GRF to be significantly greater compared to KJRF for all jumps (p<0.001). Regression analysis indicated a linear relationship between GRF and KJRF for all the jumps. The R2 values for each jump were CMJ=0.990; DJ=0.993; SLJ=0.995. These results indicate that GRF data may be a viable alternative for assessing KJRF.