👩‍🦰 Does the menstrual cycle influence muscle gains from exercise?

It is believed that muscle mass in response to exercise is affected by the menstrual cycle phases and hormones.

The follicular phase is believed to support the building of muscle mass compared to the luteal phase.

A novel study wanted to find out if this is true and assessed the influence of menstrual cycle phases on muscle mass gains and losses in response to 6 days of controlled resistance exercise.

The volunteers were young females who exercised either during the late follicular phase or mid-luteal phase.

Exercises was a unilateral resistance exercise (i.e. using only 1 limb) in each menstrual cycle phase. For example, training the left leg during the follicular phase and the right leg during the luteal phase.

Exercise resulted in a significant increase in muscle mass, but the menstrual cycle phase had no direct effect on muscle gains or losses, or on muscle metabolites in the blood.

This means that muscle is not more or less responsive to growth in response to exercise in a given menstrual cycle phase.

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The confusing and complex cycle syncing recommendations can be left behind as fluctuations in ovarian hormones did not influence muscle growth nor loss in response to exercise.

💊 Does the ‘pill’ affect muscle growth from training?

This is a persistent question among gym goers and sport people, with may different opinions.

There is speculation that the contraceptive pill use affects skeletal muscle biology in response to resistance exercise

A recent study investigated if the active or inactive phases of the ‘pill’ had any effects on muscle protein growth (or loss) when exercising.

For clarity, the active ‘pill’ phase was week 2 of a monthly active ‘pill’ cycle, while an inactive ‘pill’ phase was the final week of a monthly ‘pill’ cycle.

The results showed:

1. No significant difference in muscle growth or loss between the active and inactive ‘pill’ phases

2. Resistance exercise significantly stimulated muscle growth in both phases, with no variation based phases

This means that the ‘pill’ phase phase does not influence muscle protein turnover in females and does not promoted a significant catabolic or anabolic effect.

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Women can ignore any fearmongering about oral contraceptives stealing their ‘gains’ when training.

💊 Does the ‘pill’ affect power and strength in trained women?

To follow up from the article above, a review of multiple studies investigated if the ‘pill’ has any impact on power and strength in trained women.

The results indicate that the ‘pill’ does not have a significant effect on muscle mass, power or strength in response to resistance training.

This means that there is no evidence-based rationale to advocate for or against the use of the ‘pill’ in females who perform resistance training to increase muscle mass, power and/or strength. Rather, an individualised approach considering an individual’s response to contraceptives, their reasons for use and menstrual cycle history may be more appropriate.

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If you’re a a gym goer, athlete or coach concerned about the effect of contraceptives on strength training outcomes, research does not support modifying training strategies based on contraceptive use alone.