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Published on: January 26, 2018
The muscle stretch reflex throughout the menstrual cycle.
Ellen Casey1, Farah Hameed, Yasin Y Dhaher
11Sensory 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.
Medicine and Science in Sports and Exercise
|October 5, 2013
Summary
The muscle stretch reflex (MSR) in the rectus femoris muscle varies during the menstrual cycle, showing a significantly lower response around ovulation. This finding may help explain sex differences in sports injuries.
Area of Science:
- Sports Medicine
- Neuroscience
- Endocrinology
Background:
- Sex disparities in sports injuries suggest differences in motor control.
- Sex hormones may modulate these movement patterns and injury risks.
Purpose of the Study:
- Investigate muscle stretch reflex (MSR) fluctuations across the menstrual cycle.
- Hypothesize MSR changes correlating with estrogen levels.
Main Methods:
- Measured MSR, anterior knee laxity (AKL), and sex hormone levels in 19 women (eumenorrheic and on oral contraceptives) across their cycles.
- Assessed quadriceps muscle MSR response.
Main Results:
- Rectus femoris MSR was significantly lower (2.4x) in the periovulatory phase vs. luteal phase.
- Vastus medialis MSR showed a similar trend, but not statistically significant.
- No significant association found between MSR, hormone levels, or AKL.
Conclusions:
- Rectus femoris MSR response varies cyclically, lowest near ovulation.
- Further research is needed to clarify the role of sex hormones and AKL in MSR changes.
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