Ground reaction forces and dominant leg kinematics during a rapid stop and jump

The purpose of this investigation was to examine ground reaction forces and dominant leg kinematics during a run followed by a rapid stop and a vertical jump. Eight elite collegiate basketball players performed three trials each. Three high speed video cameras recorded the position of selected anatomical markers while force data were recorded. Vertical ground reaction force at impact ranged from 1.6 to 4.25 times body weight. The pattern of the waveform was unimodal in three cases and bimodal in five. Anterior-posterior ground reaction forces at impact ranged from 0.5 to 2.5 times body weight. Five subjects demonstrated flexion at the hip during the landing phase. The other subjects maintained a constant hip angle until the propulsion phase of the jump was initiated. The subjects contacted the ground with the knee approximately ten degrees from full extension. The knee then underwent rapid flexion. VGRF is similar to that reported in the literature for landing from a jump. APGRF is markedly larger than that seen in running. The effect of this force on joint kinetics and possible joint injury needs to be examined.