Landing Posture in Elite Female Athletes During a Drop Vertical Jump Before and After a High-Intensity Ergometer Fatigue Protocol: A Study of 20 Japanese Women's Soccer League Players

Background:Even elite athletes, who usually show stable postural control, sometimes cannot control their posture after high-load training. This instability may contribute to anterior cruciate ligament injury. Purpose/Hypothesis:The purpose of this study was to evaluate the landing posture of elite female soccer players before and after a novel high-intensity fatigue-inducing exercise protocol. We hypothesized that the landing posture will change before versus after the fatigue protocol. Study Design:Descriptive laboratory study. Method:The study participants were 20 female elite soccer players. All athletes performed 3 drop vertical jumps (DVJs), pedaled an ergometer 8 times with full force for 10 seconds each (fatigue protocol), and then repeated the 3 DVJs. We measured and compared the athletes' blood lactate levels before and after the fatigue protocol, as well as the hip flexion, knee flexion, and ankle dorsiflexion angles and final landing posture during the DJVs. Results:Blood lactate levels increased significantly pre- to postprotocol (from 2.7 +/- 1.9 to 15.0 +/- 3.6 mmol/L; P < .001), while there were decreases in hip flexion angle (from 35.0 degrees +/- 11.2 degrees to 22.4 degrees +/- 8.8 degrees; P < .001) and ankle dorsiflexion angle (from 26.4 degrees +/- 3.9 degrees to 20.0 degrees +/- 3.7 degrees; P < .001). The number of athletes who could not maintain a stable DVJ final landing posture increased from 10% before the fatigue protocol to 70% after. Conclusion:The elite female athletes in our study showed significant decreases in hip flexion and ankle dorsiflexion angles in the DVJ landing after a fatigue-inducing protocol. Most elite athletes were unable to maintain a stable posture on the DVJ landing after the fatigue protocol.