The muscle pre-activity timing of the hamstrings and quadriceps during 180° and 360° rotational jump landings in healthy female subjects

Abstract Background/Objective The muscle activity before the initial contact between during jump landings is referred to as the pre-activity. The muscle pre-activity that occur during jump landing are considered to be an important predictor of non-contact anterior cruciate ligament (ACL) injury risk. ACL injury prevention programs have been widely conducted; these programs are generally focused on increasing the muscle pre-activity and include rotational jump landing. The purpose of this study was to investigate the timing of the muscle pre-activity of the hamstrings and quadriceps during 180° and 360° rotational jump landing. Methods The participants were 10 healthy females. Electromyography was conducted on the knee joint muscles of the left leg (the non-dominant leg) during clockwise 180° and 360° rotational jump landings. Results The muscle pre-activities during 180° rotational jump landing was VM: 35.68 ± 11.22 msec, RF: 38.05 ± 14.77 msec, VL: 47.10 ± 19.96 msec, BF: 115.63 ± 30.48 msec and SM: 136.45 ± 47.52 msec. And the muscle pre-activities during 360° rotational jump landing was VM: 45.25 ± 17.41 msec, RF: 42.38 ± 13.35 msec, VL: 48.75 ± 19.20 msec, BF: 132.20 ± 46.74 msec and SM: 140.70 ± 40.64 msec. For both the 180° rotational jump landing and the 360° jump landing, the pre-activities of the hamstrings occurred significantly earlier than those of the quadriceps (p  Conclusion The results of the present study indicate that it may be beneficial for ACL injury prevention programs to include rotational jump landing tasks.