Since last August, Chelsea Women’s Football squad (who currently are second in Women’s Super League) started designing player’s individual plans around the phases of their menstrual cycle, in an attempt to enhance performance and cut down on injuries. The players use a tracker and log their symptoms and their coaches adapt their training and schedules. This is a revolutionary initiative that every woman should look into, as it could be the start of a large-scale change in the way that female athletes train.
Relative research shows that during the menstrual cycle several fluctuations in sexual hormone levels occur, depending on the cycle?s phase. The phase that affects the soft tissues (muscles, tendons, ligaments) in the female body the most is ovulation, due to its hormonal profile. Specifically, estrogen and relaxin, two of the primary female sex hormones, peak at ovulation and have been specifically studied regarding their relationship to human connective tissues.
Due to the higher rate of non-contact ACL tears in women compared to men, many studies have investigated the effect of the menstrual cycle on the knee stabilizing muscles such as the quadriceps and hamstring and ACL laxity. The results on female collegiate athletes demonstrated that whose serum relaxin concentrations were higher than 6.0 pg/ml (average value at ovulation phase) had more than 4 times increased risk for anterior cruciate ligament (ACL) tears. The reason for that is that relaxin significantly upregulated intracellular processes in female ACL cells, something that alters the structural integrity of ligaments over time. These alterations may reduce the load bearing properties of female ACL and contribute to non-contact ACL injuries.
Another area highly investigated is the ankle, with a greater focus on the Plantar fascia and the Achilles tendon. The results from relative studies indicate that, plantar fascia thickness, when not under load, does not change when comparing menstruating with ovulating women. However, when a load was applied by having the participant stand on 1 foot, the plantar fascia thinned more and the foot lengthened more during ovulation than during menstruation. Although plantar fascia laxity was greater at ovulation compared with menstruation in women, men’s plantar fascia laxity was the same as that of menstruating women. Also, another study that compared women with normal menstrual cycle and women that used contraceptive pills showed that due to reduced hormonal fluctuations in women that used oral contraceptives, strain on the Achilles tendon was greater in women with a normal menstrual cycle and disappeared when women used oral contraceptives.
Apart from hormones, another factor that is widely examined is body temperature. Research has shown that tendons and ligaments are warmest in the ovulatory phase of the menstrual cycle and coolest during menstruation. A higher temperature could further increase ligament laxity and affect the tendons of the knee stabilising muscles. Relative studies that focused on possible laxity-related altered neuromuscular-control strategies in the lower leg at ovulation, found it to correlate with lower leg injuries and reduced motor control during hopping.
To conclude, the female body during ovulation presents certain anatomical alterations that can possibly affect your training, especially if you are training competitively, or for a marathon race for example. Women tend to feel random pains and aches on different muscles in their legs at this time, as the body tries to compensate and keep up with the same training load. The best approach is to keep track of those symptoms and if you see them correlating with your menstrual cycle, properly alternate your schedule to suit your own individual needs.
Fede, C., Albertin, G., Petrelli, L., Sfriso, M.M., Biz, C., De Caro, R. and Stecco, C., 2016. Hormone receptor expression in human fascial tissue. European journal of histochemistry: EJH, 60(4).
Fede, C., Pirri, C., Fan, C., Albertin, G., Porzionato, A., Macchi, V., De Caro, R. and Stecco, C., 2019. Sensitivity of the fasciae to sex hormone levels: Modulation of collagen-I, collagen-III and fibrillin production. PloS one, 14(9)
Lee, H. and Petrofsky, J., 2018. Differences Between Men and Women in Balance and Tremor in Relation to Plantar Fascia Laxity During the Menstrual Cycle. Journal of athletic training, 53(3), pp.255-261
Lee, H. and Yim, J., 2016. Increased postural sway and changes in the neuromuscular activities of the ankle stabilizing muscles at ovulation in healthy young women. The Tohoku journal of experimental medicine, 240(4), pp.287-294.
Sung, E.S. and Kim, J.H., 2018. The influence of ovulation on postural stability (Biodex Balance System) in young female. Journal of exercise rehabilitation, 14(4), p.638
Yim, J., Petrofsky, J. and Lee, H., 2018. Correlation between Mechanical Properties of the Ankle Muscles and Postural Sway during the Menstrual Cycle. The Tohoku journal of experimental medicine, 244(3), pp.201-207