Background Poor knee alignment is associated with increased loading of the joints, ligaments and tendons, and may increase the risk of injury. The study purpose was to compare differences in knee kinematics between basketball and floorball players during a vertical drop jump (VDJ) task. We wanted to investigate whether basketball players, whose sport includes frequent jump-landings, exhibited better knee control compared with floorball players, whose sport involves less jumping.

Methods Players (aged 12–21 years) were recruited from six basketball and floorball clubs of the Tampere City district, Finland. Complete data was obtained from 173 basketball and 141 floorball players. Peak knee valgus and flexion angles during the VDJ were analysed by 3 D motion analysis.

Results Larger knee valgus angles were observed among basketball players (−3.2º, 95% CI: −4.5 to −2.0) compared with floorball players (−0.9º, 95% CI: −2.3 to 0.6) (P = 0.022). Basketball players landed with a decreased peak knee flexion angle (83.1º, 95% CI: 81.4 to 84.8) compared with floorball players (86.5º, 95% CI: 84.6 to 88.4) (P = 0.016). There were no significant differences in height, weight or BMI between basketball and floorball players. The female athletes exhibited significantly (P < 0.001) larger peak knee valgus angles (−7.5º, 95% CI: −8.7 to −6.2) than the male athletes (3.4º, 95% CI: 2.1 to 4.6).

Conclusions This study revealed that proper knee control during jump-landing does not seem to develop in young athletes simply by playing the sport, despite the fact that jump-landings occur frequently in practice and games. Poor knee control was especially common among young female athletes. An important clinical implication of these findings is that young team sport athletes need to be taught a safer technique for landing and also need specific neuromuscular training in order to avoid potentially harmful movement patterns. (Int J Sports Med 2015, accepted for publication)