Abstract
BACKGROUND: An increase in dynamic knee valgus (DKV) is associated with knee injuries during physical activities and sports. Numerous studies have investigated the effect of fatigue on DKV during different landing tasks. This study aimed to conduct a systematic review and meta-analysis of research on the influence of fatigue on DKV across various landing tasks. METHODS: A comprehensive search was conducted in PubMed, Scopus, Web of Science, and Embase to identify relevant studies. Two researchers independently reviewed and assessed the quality of the articles using the Downs and Black checklist. Statistical analysis was performed with Review Manager software. RESULTS: From 280 studies identified, 29 met the eligibility criteria. Of these, 12 studies were conducted on single-leg landing tasks, 6 studies on single-leg vertical drop jumps, 1 study was single-leg vertical drop jump & double-leg drop landing, 1 study was single-leg drop landing & double-leg vertical drop jump, 4 studies on double-leg landing, and 5 studies conducted on double-leg vertical drop jumps. The meta-analysis provided strong evidence that fatigue significantly increased peak knee valgus during double-leg drop jumps in males (p < 0.001). Furthermore, agility and stair climbing fatigue protocols led to a significant increase in peak knee valgus during all landing maneuvers. CONCLUSION: The results of the meta-analyses showed that fatigue significantly increased peak knee valgus only during double-leg vertical jumps, with no significant effects observed in other landing tasks. Additionally, fatigue protocols involving agility and stair climbing increased DKV. Therefore, considering the type of fatigue and sports requiring double-leg landings may help prevent knee injuries. To enhance the reliability of findings on the effects of fatigue on knee joint dynamics, future high-quality studies using standardized protocols, larger sample sizes, and sport- and gender-specific analyses are recommended. TRIAL REGISTRATION: The study procedure was pre-registered on the International Prospective Register of Systematic Evaluation Procedures PROSPEROCRD42024548996.