Acute Hamstring Fatigue in Elite Male Sixes Lacrosse Players Following a Single Competitive Match

Background/Objectives: Decreases in hamstring isometric strength have been observed post-competition, but research has currently focused only on soccer players. Therefore, the purpose of the present study was to observe if acute reductions in isometric hamstring force production in elite male lacrosse players occur post-match. Methods: Peak isometric force measurements were collected from ten male outfielders from the British Lacrosse squad (24.6 ± 2.3 years, 1.80 ± 0.08 m, 86.3 ± 4.5 kg) using force plates. The 90:90 isometric assessment was conducted before and after a single sixes lacrosse match to observe changes in hamstring force production. Bayesian paired sample’s t-test and Hedge’s g effect sizes were used to determine the level of evidence and magnitude of fatigue due to sixes lacrosse match play. Results: A strong level of evidence with moderate–large effect sizes for reduced peak force was observed (Bayes factor [BF] = 11.36–12.55; g = 1.18–1.20). Stronger levels of evidence and large magnitude reductions were observed for force at 100 and 200 ms (BF = 18.92–61.85; g = 1.55–1.63). Conclusions: Sixes lacrosse match play results in localized hamstring fatigue, which could explain the high frequency of hamstring strain injuries within elite men’s sixes lacrosse players. The current sixes competition format includes multiple fixtures on a single day; therefore, practitioners need to prioritize recovery.