1Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, IL; and 2Rehabilitation and Regenerative Medicine, New York Presbyterian Hospital, Columbia University Medical Center, Columbia University College of Physicians and Surgeons, New York, NY.
Med Sci Sports Exerc. 2014 Mar;46(3):600-9. doi: 10.1249/MSS.0000000000000134.
The significant sex disparity in sports-related knee injuries may be due to underlying differences in motor control. Although the development of sex-specific movement patterns is likely multifactorial, this study specifically focuses on the potential modulatory role of sex hormones.
This study aimed to investigate the muscle stretch reflex (MSR) across the menstrual cycle. We hypothesized that the MSR would fluctuate throughout the menstrual cycle and that the lowest response would correspond with peak concentrations of estrogen.
Nineteen healthy women age 18-35 yr participated in this study: 8 eumenorrheic women and 11 women taking oral contraceptives. Serum estradiol and progesterone concentrations, anterior knee laxity (AKL), and the MSR response of the quadriceps muscles were measured three times during the menstrual cycle.
The MSR response of the rectus femoris (RF) varied significantly across the menstrual cycle in both groups. Specifically, the RF MSR response was 2.4 times lower during the periovulatory phase when compared with the luteal phase (P = 0.007). The same trend was seen in the vastus medialis, but this did not reach statistical significance (P = 0.070). The MSR response of the vastus lateralis did not change significantly across the menstrual cycle (P = 0.494). A mixed model comparison did not show an association between endogenous concentrations of estradiol and progesterone, exposure to hormonal contraceptives or AKL, and the MSR response for any muscle.
Our results demonstrate that the RF MSR response varies throughout the menstrual cycle with the lowest response around the time of ovulation. Additional research is needed to clarify the exact relationship between sex hormones, AKL, and MSR response and to determine the specific origin of the change along the monosynaptic reflex arc.
运动相关膝关节损伤中显著的性别差异可能归因于运动控制方面的潜在差异。尽管性别特异性运动模式的发展可能是多因素的，但本研究特别关注性激素的潜在调节作用。
本研究旨在调查月经周期中的肌肉拉伸反射（MSR）。我们假设 MSR 会在整个月经周期中波动，并且最低反应与雌激素峰值浓度相对应。
19 名年龄在 18-35 岁的健康女性参与了这项研究：8 名月经规律的女性和 11 名服用口服避孕药的女性。在月经周期的三个时间点测量血清雌二醇和孕酮浓度、前膝松弛度（AKL）和股四头肌的 MSR 反应。
两组的股直肌（RF）MSR 反应在整个月经周期中均有显著差异。具体来说，与黄体期相比，排卵前期 RF MSR 反应低 2.4 倍（P = 0.007）。股中间肌也出现了同样的趋势，但未达到统计学意义（P = 0.070）。股外侧肌的 MSR 反应在月经周期中没有明显变化（P = 0.494）。混合模型比较表明，雌二醇和孕酮的内源性浓度、激素避孕药的暴露以及 AKL 与任何肌肉的 MSR 反应之间没有关联。
我们的结果表明，RF MSR 反应在月经周期中发生变化，排卵时的反应最低。需要进一步研究以阐明性激素、AKL 和 MSR 反应之间的确切关系，并确定沿单突触反射弧变化的具体来源。
