Influence of a head-turned position on landing movement patterns: a crossover trial

BACKGROUND: In sports where the ball is played overhead, anterior cruciate ligament (ACL) injuries are mostly sustained during landing with athletes looking elsewhere, often with their heads turned. The purpose of this study was to examine the effect of a head-turned position on landing movement patterns and jump heights using the Landing Error Scoring System (LESS), as a means of altering sensory input to enhance sport specificity and relevance to ACL injury screening. METHODS: Thirty-five healthy adults (22 males, 13 females) participated in this within-participants crossover trial, completing three double-leg jump landings assessed under two randomised conditions allocated sequentially: control and head-turned LESS. Overall LESS scores, proportion categorised at risk (≥ 5 errors), occurrence of specific landing errors, and jump heights were compared between conditions. RESULTS: LESS scores were higher in the head-turned condition than control (6.8 ± 1.5 versus 6.4 ± 1.4 errors, P = 0.027) and jump heights lower (32.7 ± 10.2 versus 34.8 ± 10.3 cm, P = 0.002), both with small effects (Cohen's d = 0.27 [0.03, 0.51]; 0.20 [0.07, 0.34]). Under the head-turned condition, participants more often landed with lateral trunk flexion (20% vs. 54%, P = 0.002) and wide stance (23% vs. 46%, P = 0.002). Odds of being classified at risk did not differ significantly (P = 0.625, OR = 3.00 [0.31, 28.80]). CONCLUSION: Performing the LESS with a head-turned position to alter sensory input reduced jump height and increased LESS errors, but did not meaningfully alter injury risk categorisation. Future research should determine whether a head-turned condition enhances the predictive validity of the LESS for ACL injuries and use in injury prevention and rehabilitation. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ACTRN12625001299493), 21/11/2025. Retrospectively registered.