Effects of Sex and Fatigue on Biomechanical Measures During the Drop-Jump Task in Children

Abstract

Background:Female athletes have a higher rate of anterior cruciate ligament (ACL) injury than males from adolescence and into maturity, which is suggested to result from sex-specific changes in dynamic movement patterns with maturation. Few studies have studied movement strategies and response to fatigue in children.Purpose:To evaluate the effect of fatigue on biomechanical variables associated with increased risk for ACL injury during a drop-jump (DJ) performance in children.Study Design:Controlled laboratory study.Methods:A total of 116 children (mean age, 10.4 years) were recruited from local sports clubs and performed 5 repetitions of a DJ task before and after a fatigue protocol. Kinematic and kinetic data from initial contact (IC) to the first peak vertical ground reaction force (vGRF) were analyzed for both limbs, including limb and fatigue as within-subject factors for analyses between boys and girls. Pearson correlation coefficients were calculated to identify associations between variables of interest.Results:Girls demonstrated greater peak vGRF values than boys (by 8.1%; P < .05), there were greater peak vGRF values for the right limb than the left (by 6.2%; P < .001), and fatigue led to slightly greater values (P < .05). Although weak, the correlation between peak vGRF values and knee flexion excursion was stronger for girls (r = –0.20) than boys (r = –0.08) (P < .006). Fatigue resulted in greater knee flexion angles at IC and less excursion during landing, more so for girls (by 6.1° vs 1.4°; interaction, P < .001), although the knee flexion moment was generally lowered by fatigue (P < .001). Limb asymmetry in knee flexion moments was more pronounced for boys than for girls (interaction, P < .05), contrary to that seen in frontal plane knee moments, where asymmetry was much greater in girls than boys (interaction, P < .001).Conclusion:Even as young athletes, girls and boys seem to adopt dissimilar movement strategies and are differently affected by fatigue.Clinical Relevance:Injury prevention programs should be considered at an earlier age in an effort to lower the risk of ACL injury in athletes.

Effects of Lower Extremity Muscle Fatigue on Knee Loading During a Forward Drop Jump to a Vertical Jump in Female Athletes

“…As shown in Table 1, the knee flexion angle increased at initial ground contact, but the knee ROM during the landing phase decreased significantly under muscle fatigue condition. These results are consistent with a previous study, which showed that fatigue resulted in greater knee flexion angles at initial ground contact and less excursion during the landing (Briem et al, 2017). Blackburn and Padua (2009) posited that a larger trunk flexion angle during landing caused larger hip and knee flexion angles; moreover, a landing with the trunk flexion effectively reduced vertical GRF and quadriceps myoelectric amplitude.…”

“…The biomechanical influence of the landing has a greater effect on the legs of female athletes than of male athletes. Studies have indicated that female athletes exhibit larger knee flexion angles during initial ground contact, less knee angular displacement during the landing, greater vertical GRF and greater posterior GRF, greater anterior tibial shear force, and less total lower extremity energy absorption than male athletes during the landing (Briem et al, 2017). These have been reported as crucial factors influencing the occurrence of ACL injuries in female athletes.…”

Timing, not magnitude, of force may explain sex-dependent risk of ACL injury

“…In addition to cutting maneuvers, biomechanical data collection included bilateral drop jumps and strength testing not included in this report. The methods of data collection are described in detail elsewhere [ 5 ]. An 8-camera motion capture system (Qualisys Corporation, Göteborg, Sweden) sampling at 200 Hz was used.…”

Children’s Single-Leg Landing Movement Capability Analysis According to the Type of Sport Practiced

“…Landing in its different forms, such as single-leg landing (SLL) [ 5 , 6 , 8 , 9 , 10 ] is frequently used as a motor task during physical activity and is commonly used for studying motor pattern development in addition to dynamic postural stability and injury prevention. Landing, an integral part of sports [ 11 ], is a discrete task with a different beginning and end, without a continuous cyclic pattern [ 12 ].…”