Repetitive jumping and sprinting until exhaustion alters hamstring reflex responses and tibial translation in males and females

Abstract

The incidence of anterior cruciate ligament injuries is considerably higher in females than in males and the underlying mechanisms are still under debate. Research indicates that the neuromuscular system of females and males might respond differently to the same fatigue protocol due to differences in muscle activation during movement tasks. This study analyzed sex differences in hamstring reflex responses and posterior-anterior tibial translation (TT) before and after fatiguing exercise. We measured the isolated movement of the tibia relative to the femur as a consequence of mechanically induced TT in standing subjects as well as muscle activity of the hamstrings before and after repetitive jumping and sprinting until exhaustion. Muscle fatigue delayed reflex onset latencies in females and males. A reduction in reflex responses associated with an increased TT was observed after fatiguing exercise for both sexes. Data indicate that the used fatigue protocol altered the latency and magnitude of reflex responses as well as TT in females and males. Based on the results of previous research and the outcome of this study, it might be that sex-specific effects of fatigue on reflex activity and mechanical stability of the knee depend on the kind of fatiguing exercise.

Combined Effects of Fatigue and Surface Instability on Jump Biomechanics in Elite Athletes

“…In contrast, in the present study we investigated the effects of repetitive double-leg box jumps on onset/peak knee flexion angles in elite volleyball players. In accordance with previous findings of Behrens et al [2], it can be postulated that sex-specific effects of fatigue on mechanical knee joint stability depends on methodological approaches such as the applied fatigue protocol, the testing protocol, and/or the examined population.…”

Lesiones del ligamento cruzado anterior en esquiadores: Conceptos actuales

“…It should be considered that the hamstring muscles act as ACL agonists to resist anterior tibial translation, 12,13 which is consistent with the study by Behrens et al, 14 who demonstrated that impaired hamstring neuromuscular function and acute fatigue result in increased tibial translation and ACL tension.…”

Change in knee flexor torque after fatiguing exercise identifies previous hamstring injury in football players

“…This indicates that specific hamstring, but not whole limb, fatigue may be a factor influencing hamstring injury risk and tends to be left deconditioned after return to play. Furthermore, the power of the test to identify previous injury might speculatively indicate that general fatigue‐related weakness or loss of structural integrity of the muscle directly predisposes it to injury or that the test might detect individuals whose rapid fatigue responses might exacerbate typical fatigue‐related alterations in reflex activation of muscle during lengthening contractions, which may increase injury risk. However, further research is required to both replicate the current findings and determine the factors contributing to its power to detect previously injured muscles.…”