Compensatory Mechanisms in Basketball Players with Jumper’s Knee

Abstract

Determining whether there are compensations in those with jumper's knee (JK) might further our understanding of the condition. Comparing lower extremity kinematics and jump performance of basketball athletes with JK with those of healthy controls (C). Repeated-measures control-match design. University laboratory. 24 male basketball players (12 JK, 12 C) matched by height, weight, position, experience, and frequency of play. Standing counter-movement and running layup jumps. Maximum vertical-jump height, footfall landing, and lower extremity sagittal-plane kinematics. There were no significant group differences (P > .05) in vertical-jump height (JK = 64.3 +/- 8.6 cm, C = 63.0 +/- 9.8 cm) or layup height (JK = 71.3 +/- 11.6 cm, C = 73.3 +/- 11.0 cm). JK subjects landed flat footed (50%) more than controls (8%). JK subjects showed significantly more hip flexion (JK = 105 degrees +/- 24.8 degrees, C = 89.8 degrees +/- 14.1 degrees; P = .039) with decreased hip acceleration during the countermovement (JK = -3039 +/- 1392 degrees /s2, C = -4229 +/- 1765 degrees /s2; P = .040). When landing from the countermovement jump, JK subjects had significantly less knee acceleration (JK = -4960 +/- 1512 degrees/s2, C = -6736 +/- 2009 degrees/s2, P = .023) and in the layup showed significantly less ankle dorsiflexion (JK = 106.5 degrees +/- 9.0 degrees, C = 112.5 degrees +/- 7.7 degrees; P = .048) and hip acceleration (JK = -2841 +/- 1094 degrees/s2, C = -3912 +/- 1575 degrees/s2; P = .033). Compensatory strategies observed in JK subjects might help maintain performance, because their jump height was similar to that of healthy controls.