Vertical Ground Reaction Force-Time Curve Differences Between the Two Landings of a Drop Vertical Jump. Implication For ACL Injury Risk

Abstract

Vertical drop jump consists two landings of which the first one is the most frequently analysed one. Aim of this paper was to compare kinetic patterns between first and second landings and dominant and non-dominant leg between landings by analysing force-time curves and their variability across landings. 44 top level female handball players (N = 25) and volleyball players (N = 19) of average age 24 ± 4 y, height 181.1 ± 7.8 cm and weight 72.4 ± 8.0 kg agreed to participate in this study. Each subject completed 4 successful drop jumps from an initial height of 30 cm on two parallel ground reaction force platforms. Force-time curve analysis revealed significant differences (p < .05) in certain parts of the cycle between the two landings for each leg. Moreover, significant differences (p < .05) were found between dominant and non-dominant leg solely in the second landing. Second landings were shown to be significantly more variable (p < .001) than the first ones. Results of the current study confirm previous findings of different neuromuscular pathways used in two landings thus indicating a possible increased risk of ACL injury which highlights the importance of second landing analysis in drop vertical jump.