Fascial changes in response to hormones is a topic that piques my curiosity and is benefiting from increasing scientific research and focus, especially among my Yoga Medicine colleagues. It always brings me to think of a pivotal life period.
As a teenager, while taking a layup at basketball practice, my left knee audibly “popped” and I crumbled to the court in pain. After some ice, and a break on the side-lines, I was encouraged to get back on the court to train. A few days later I was diagnosed with a total ACL rupture - a ligamentous tear in the knee joint and was scheduled for reconstructive orthopedic surgery and the sidelines, again. That one injury, set the trajectory for two knee replacements twenty years later, and a deep love affair with yoga, the body and its incredible ability to heal from the inside out. What I didn’t know at the time of my initial knee injury is what research has shown today - that female hormonal processes influence our propensity for over-stretching scenarios and injury.
Here’s how that happens.
Collagen (for which there are 5 unique types or blends) is the main structural protein in the extra-cellular matrix found in connective tissue. Fascia is classified as a type of connective tissue, and ranges in density and texture depending on its location in the body. During ovulation, estrogen increases creating an increase in elastic and more lax-quality Type 3 Collagen fibers in the fascial matrix, and a reduction in rigid-quality Type 1 Collagen, the fibers which provide stability. The ACL - the anterior cruciate ligament - stabilizes the femur (thigh bone) and tibia (in the lower leg) within the capsule of the knee joint. (It's most commonly torn during sports that involve sudden stops and changes in direction.) During ovulation therefore, the knee is its least stable, compared to times outside of the ovulation cycle. Potentially a factor in my own ACL rupture or tear, there is higher knee joint laxity in the first 1/2 of the menses cycle, increasing the risk of an ACL injury - especially if paired with exercises done in a hot environment.
Another common cause and effect for the facial matrix increasing in Type 3 Collagen and decreasing in Type 1 Collagen, results in the propensity of the Plantar Fascia on the bottom of the foot and heel to thin during ovulation - as well as pregnancy. This “thinning” of the plantar fascia increases foot length and reduces one’s sense of balance, leading to a proprioceptive challenge. For runners specifically, this could lead to changes in the “feel” of the running stride, consequently necessitating an adaptation at this time of their training cycle - if of course they are equipped with this information ahead of time.
Generally speaking, it can be concluded that women normally “more flexible”, become “really flexible” during ovulation, whereas women who tend to “feel tighter” consistently, generally feel "better" during ovulation.
Yet it’s not enough to discern ovulation as a singular process that alters the female body but other factors like temperature also need to be considered. Temperature is a factor that can influence susceptibility to injury and can come into play depending on the style and of yoga being practiced and the degree of intensity to which it is practiced during menses.
Research has shown an increased risk for over-stretching and injury when practicing Yin Yoga or performing exercise or a workout in a hot environment - and that this risk is at its peak during the first 1/2 of the menses cycle. Therefore, hot exercise and targeting longer, somewhat deeper holds as in Yin Yoga, is best slotted in “post-period”, and post any weight-bearing workout. Yin Yoga poses nourish our introspective side and when practiced post-period supports development of follicles and endometrium in that phase of the cycle. Evidence there’s always more happening than just the sweetness of the yoga stretch itself!
So it is important to keep in mind that as temperature increases, the risk of injury also increases. Temperature will affect loose connective tissue the most - increasing the hyaluronic molecules that deliver slide and glide-ability throughout the tissue layers, but at the same time also bring increased laxity to the deeper fascia beneath, setting up the potentiality for over-stretching.
Particular to athletes, in certain phases of athletic training cycles, this could affect things that disrupt athletic performance and increase the risk of injury. For anyone wanting to better tune in to training according to their hormonal cycle - it is recommended to follow the 60% rule when incorporating yoga during menses. Meaning, to reduce the risk of placing too much demand and load on ligaments and tendons, the athlete should “work” at 60% of their maximum effort or “stretch capacity” when practicing yoga during menses.
Regardless of athletic ability, for women in menopause, lower hormone levels lead to more Type 1 Collagen tissues within the facial matrix - the rigid tissues that feel more stiff - and a reduction in Type 3 Collagen tissues - the more lax fibers that elicit a sense of elasticity and give. These changes can affect a person’s economy of movement, and create stiffness where things may have once felt more elastic and flexible.
As women age, the beginning phases of peri-menopause will likely be characterized by change and flux before the later phases of menopause set it, and things begin to "normalize". This is especially noticeable in orthopedic patients, where the presence of scar tissue (a denser form of unorganized connective tissue) creates stiffness and discomfort around joints and can decrease a joint's responsiveness. As a bilateral knee replacement patient I have become personally aware of my unique influencing factors when it comes to movement, and have implemented adaptations into how I manage my own workout schedule, which yoga poses suit me best during ovulation, and in planning for the clients I work with privately, whom, like myself, I’m aware are in the flux of this transitory experience. Without awareness, the best decisions in the interest of the individual aren't possible.
This is such interesting science that can help inform how women integrate yoga into an existing training plan AND for women practicing yoga outside of any regular athletic training or goal-oriented plan. Women - and men - becoming informed with heightened awareness - and, if applicable, responsibilities to train females in a sport in the most sensible way - brings autonomy to the depth of our inner-connection and inner-understanding and even to our outward inter-relating, with one goal: maximizing resilience regarding our internal health, decreasing our propensity for injury and future imbalances, making wiser decisions and igniting greater awareness for communal wellness. Want to know more about developing a confident yoga practice that addresses both your present and future inner wellness and can reduce your propensity for injuries? I fuse the latest scientific research and my deeper understanding of anatomy and physiology into my yoga classes creating greater awareness, autonomy, body connection, safety and movement confidence for the students who take classes with me. Students learn information and movement relatable to their lives and body, in small series and are then encouraged to self-apply in real time, routinely, to develop self-understanding and resilience in time away from teacher-led classes.
Why not check out a short 5 class series to start moving and taking care of yourself in the new year in a more informed way? Small group 5 class series run Tuesdays at 5:30 pm, Wednesdays at 10:30 am and 6:15 pm and begin Jan. 3, 2023, with a second round beginning on February 21.
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References Katja Bartsch, Sports Scientist & lead Yoga Medicine Researcher. Yoga Medicine Research Lecture Notes. Tiffany Cruikshank, Yoga Medicine Founder, Lead Teacher; Yoga Medicine Research Lecture Notes.
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Petrofsky J, Lee H. Greater Reduction of Balance as a Result of Increased Plantar Fascia Elasticity at Ovulation during the Menstrual Cycle. Tohoku J Exp Med. 2015 Nov;237(3):219-26. doi: 10.1620/tjem.237.219. PMID: 26537843.