Age-Related Differences in Functional Hamstring/Quadriceps Ratio Following Soccer Exercise in Female Youth Players: An Injury Risk Factor

Abstract

Altered muscular control following soccer-specific exercise is age dependent with players' 1-year post-peak height velocity at greatest risk of injury. Injury prevention and screening need to be age and maturation appropriate, should consider the effects of fatigue, and include movements near full extension.

Does maturation influence neuromuscular performance and muscle damage after competitive match‐play in youth male soccer players?

“…Thus at least for the large muscle groups that help to control knee joint stability the effect of fatigue is negligible and neuromuscular performance is maintained reducing the risk of injury. Our findings tentatively support previous work that suggests that there may be development of fatigue resistance with chronological age and training status that help to protect the joint (De Ste Croix et al, 2017, 2018). The reason why we have found different results to most previous studies examining match related fatigue on neuromuscular function in youth soccer players might be attributed to the fact that we used competitive match‐play to induce load on players rather than simulated match‐play.…”

“…However, the authors are cautious as they conclude that the effects of fatigue on neuromuscular function during adolescence has scarcely been studied, despite this knowledge being able to contribute to the management of training load and recovery in maturing children (Ratel & Martin, 2015). Only a few studies have explored the interaction between chronological age and fatigue on muscular and neuromuscular control and these are mainly based on female players and/or do not explore maturational stage (De Ste Croix et al., 2018; Lehnert, De Ste Croix, Xaverová, et al., 2017; Lehnert, De Ste Croix, Zaatar, et al., 2017). Such studies have also predominantly used simulated rather than competitive match play to explore fatigue related changes in injury risk mechanisms.…”

Effects of a Football Simulated Exercise on Injury Risk Factors for Anterior Cruciate Ligament (ACL) Injury in Amateur Female Players

“…However, most studies that have calculated the conventional (H con /Q con ) or functional (H ecc /Q con ) H/Q ratio have used the peak torque values, which usually occur mid-range [7], while it is well established that ACL injuries occur close to knee extension [8]). A better characterisation of players' injury risk should involve looking at the entire torque-angle relation [7], or specifically at angles close to extension [9]. In addition to the level of force produced by the hamstring, it appears that its capacity to quickly produce force (rate of force or torque development) is a strong predictor of ACL injuries in female elite team sport players [10].…”

The Role of Strength-Related Factors on Psychological Readiness for Return to Sport Following Anterior Cruciate Ligament (ACL) Reconstruction

“…Our findings on angle-specific torque, together with the absence of significant differences between groups in peak torque, highlight the importance for physiotherapists to address strength deficits across the full range of motion and consider sport-specific mechanics (i.e., movements such as landing or side cutting, where the knee might not be very flexed, supporting stipulations made by Hammond [24], who similarly reported strength deficits between specific angles, where >90% LSI was achieved during peak torque assessments). The importance of the capacity to produce high torque when the knee is close to full extension has also been highlighted in a study on fatigue in female footballers, showing that H ecc :Q con was significantly reduced after a simulated match only between 0 and 10 • from full knee extension [34]. This highlights the reduced capacity of the hamstring to stabilise the knee joint close to extension in a fatigued state, where ACLI occurs, and highlights the importance of addressing residual strength deficits at these angles during rehabilitation.…”

“…The following variables were calculated as the average of the two best contractions at 60 • •s −1 and the three best contractions at 180 and 40 • (H ecc40 , Q con40 , H ecc :Q con40 ) from full knee extension. These were calculated as averages between 0-10 • , 11-20 • , 21-30 • , and 31-40 • , respectively [34]. -Quadriceps and hamstrings RTD in the first 50 ms and the first 100 ms (RTD 50 and RTD 100, N•m•s −1 ) for H ecc , Q con , and H ecc /Q con , calculated as the ratio between the change in torque and the corresponding change in time in the first 50 ms and 100 ms of contraction, respectively.…”