Does the menstrual cycle influence flexibility?
Undoubtedly sex hormones estrogen and progesterone impact the tissue extensibility of those who menstruate or have ceased menstruation. However, the impact of the menstrual cycle on a personās flexibility is unique. Flexibility is so much more than just the range available to a joint/ extensibility of tissue, and other biological and psychosocial factors can play a more significant role in a personās flexibility.Ā
Studies that consider injury rates, range of motion and tissue extensibility at different phases in the menstrual cycle have resulted in conflicting results. This may be due in part to significant variability in hormone levels and menstrual phases between individuals. Itās also difficult to isolate the effect of individual sex hormones on the musculoskeletal system as they interact together to affect tissues. It may be that the relationship between estrogen and progesterone is more important than the actual level of each hormone. In addition, some people are likely more impacted by the level or balance of these sex hormones, such as those with joint hypermobility or connective tissue disorders.
What do we know?
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-There are estrogen and progesterone receptors in bone, skeletal muscle, ligament and tendon tissue, meaning the secretion of estrogen and progesterone influences these tissues.
-Together, both estrogen and progesterone have a positive influence on the musculoskeletal system. There is a significant increase in injuries after menopause, at least in part due to decreases in these hormones.
-Progesterone stimulates bone growth and repair. Itās likely a decrease in progesterone at menopause contributes to reduced bone density and increased risk of osteoporosis.
-Estrogen is important for muscle mass and strength. The drop in estrogen seen at menopause leads to reduced muscle strength and reduced muscle bulk.Ā
-Estrogen seems to increase the collagen content of connective tissue. Collagen is fluid dense and provides elastic qualities to tissues. This helps tendons and ligaments transfer load and is cited as a reason why those who menstruate tend to have fewer musculoskeletal injuries than other groups (e.g. less hamstring injuries than males). Conversely, increased tendon and ligamentous laxity is known to increase an individualās risk of joint injuries.Ā
-Systematic review of multiple studies has demonstrated that those who menstruate are more likely to sustain an anterior cruciate ligament (ACL) injury during menstruation or prior to ovulation. It seems that this is in part due to the effect of increased estrogen levels at this time. It is hypothesised that estrogen results in increased ligamentous laxity at this time and may also affect motor control and reduce stretch reflex sensitivity.
-Progesterone seems to increase tolerance to pain and reduce pain sensitivity which tends to result in increased flexibility.
- The hormone relaxin is also released cyclically throughout the menstrual cycle during ovulation and again on day 20 (mirroring peak progesterone levels). Relaxin has a significant role in late-stage pregnancy, increasing ligamentous laxity and pelvic mobility to increase the extensibility of the birth canal.
What does this mean for your flexibility training?
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Your menstrual cycle may have a large impact on your flexibility training, or it may have little influence.
It seems that most people who menstruate notice increased tissue extensibility just prior to ovulation, however some studies suggest that the peak estrogen at this time may also reduce motor planning and proprioception, which would usually negatively affect flexibility. The influence of relaxin could explain increased flexibility following ovulation.Ā
Estrogen and progesterone affect all body systems, not just the musculoskeletal system. Premenstrual syndrome (PMS) is a common condition affecting people who menstruate and tends present with increased anxiety, irritability, mood swings and emotional liability. We know that thoughts, beliefs, and emotions can hugely impact a personās flexibility training. Interestingly, people tend to have increased tolerance to pain at this time, meaning some people will be at their most flexible, while others will find flexibility training more difficult. It may be that changes in energy levels or the practicalities of managing menstrual bleeding have more impact on a personās flexibility training than other factors associated with the menstrual cycle.
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What next?
-If you donāt track your menstrual cycle, start.
-Try to identify when in your cycle your training is most and least effective and why. For example: is your training better because you have energy, feel well-rested, find it easier to get deeper, feel motivated to train, have better coordination/body awareness or pain isnāt bothering you as much?; Or is your training impacted because you feel stiffer/ more lax, fatigued, unmotivated, emotional, distracted or more sensitive to pain? If you have an idea why your training is more or less effective at a specific time in your cycle you can use this information to optimise your training-If you donāt notice any pattern, thats ok. It probably means other factors impact your flexibility training more than your menstrual cycle.Ā
-If you think your menstrual cycle significantly impacts your flexibility training, trial matching your program to your cycle. For example: plan eccentric loading and maximal isometrics when you will feel energised, motivated and strong; work on skills when you know your balance, proprioception, and coordination will be highest; plan to challenge your range when you know you will be most flexible; and focus on submax, supported and strength through range when you tend to feel sensitive, distracted or irritable. As there are so many variables involved, these times will be personal to you. As always, I encourage flexible programing. Listen to and honour your body over any programming, even when it is based on your cycle.
-If you are hypermobile, have a connective tissue disorder or are at increased risk of musculoskeletal injury, and you notice that you tend to injure yourself more frequently at a specific time in your cycle, you should discuss this with your health care team. It may be beneficial for you to modify your training around this time to reduce the risk of injury or hormonal interventions may be appropriate.
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Conclusion
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Your menstrual cycle will impact your flexibility training in ways unique to you. If the impact seems significant, it may be worth programing your flexibility training around your cycle to optimise your results. Itās worth seeking professional support if you believe that hormonal changes in your cycle increase your joint instability or contribute to injuries. For most people, prioritising consistent, goal-specific, responsive training that focuses on weaknesses will have a bigger impact on flexibility than factors associated with the menstrual cycle.
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