Patellar tendon properties with fluctuating menstrual cycle hormones

Area of Science:

• Sports Medicine
• Human Physiology
• Biomechanical Engineering

Background:

• Skeletal muscle performance and injury risk may fluctuate during the menstrual cycle.
• Tendon properties are crucial for muscle function and injury prevention.
• The relationship between menstrual cycle phase, hormones, and tendon properties requires further investigation.

Purpose of the Study:

• To investigate the association between menstrual cycle phase, female sex hormone levels, and patellar tendon properties.
• To determine if acute changes in hormones during the menstrual cycle affect tendon mechanical characteristics.

Main Methods:

• Assessed in vivo patellar tendon properties and circulating estradiol and progesterone levels in 15 healthy females across three menstrual cycle phases.
• Utilized dynamometry, ultrasonography, and electromyography for mechanical assessments.
• Employed biochemical assays for hormone level determination.

Main Results:

• No significant differences in tendon mechanical properties were observed across the menstrual cycle phases.
• Estrogen and maximal voluntary tendon force explained 17.8% of the variance in Young's modulus.
• Findings suggest a chronic rather than acute impact of estrogen on tendon behavior.

Conclusions:

• Menstrual cycle phase does not appear to acutely influence tendon mechanical properties.
• Estrogen's effect on tendon properties is likely chronic, impacting overall tissue characteristics.
• Tendon properties may not necessitate consideration of menstrual cycle phase in training and competition scheduling.