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Erschienen in:
01.01.2014 | Sports Medicine
The effect of sex and fatigue on lower limb kinematics, kinetics, and muscle activity during unanticipated side-step cutting
Erschienen in: Knee Surgery, Sports Traumatology, Arthroscopy | Ausgabe 1/2014
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Purpose
To determine how sex and fatigue affect lower limb kinematics, kinetics, and muscle activity during unanticipated side-step cutting.
Methods
Twenty-three physically active subjects (men 11, women 12) performed 10 successful trials of cutting manoeuvres each to either side under unanticipated conditions in response to 2 light emitting diodes before and after fatigue conditions. Data were analysed and compared regarding sex and fatigue conditions using two-way repeated measures analysis of variance.
Results
After fatigue-inducing exercise, women demonstrated larger impulses of ground reaction force (IGRF) during the first 50 ms (2.4 ± 0.8 vs. 2.1 ± 0.9, P < 0.05) than did men. Significant primary effects of sex indicated that women showed a smaller hip flexion angle at initial contact (40.4 ± 6.9° vs. 49.7 ± 9.1°, P < 0.05) and at maximum flexion angle (41.3 ± 7.7° vs. 51.4 ± 9.0°, P < 0.05) compared with men. Significant primary effects of fatigue were observed in the gluteus maximus muscle during 50 ms before initial contact (+21.5 ± 48.3 %, P < 0.05) and in the semimembranosus muscle during 50 ms before initial contact (−6.2 ± 20.1 %, P < 0.05) and the first 50 ms of side-step cutting (−7.9 ± 26.6 %, P < 0.05).
Conclusions
Our results suggest that sex differences, especially larger IGRF in a fatigue state combined with less hip flexion angle, lead to women having a higher risk for anterior cruciate ligament (ACL) injury. These findings may contribute to understanding the underlying mechanism of injury and development of preventive exercises against ACL injury.
Level of evidence
Prospective comparative study, Level II.