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A woman's menstrual cycle is a natural and healthy part of a woman's reproductive health. The fact that most people don't
call the menstrual cycle by its scientific name but use code words to describe
it creates a cultural taboo that leads to many negative impacts on female
The menstrual cycle has been treated as something to be shameful and fearful about so many athletes never tells anyone. The negative impacts of this taboo can lead female athletes to experience many menstrual challenges, including the "female athlete triad (more details in a future article)," which is three interrelated dysfunctions that happen when a female athlete either overtrain or goes through an extreme caloric restriction [1.]
As coaches, it is our duty and responsibility to be well informed about the effects of the menstrual cycle on female athletes. Becoming educated about the menstrual cycle should be a prerequisite for ANY coach that is seeking to train female athletes.
What is the menstrual cycle?
The menstrual cycle is the monthly hormonal cycle (typically 28 days) a female's body goes through to prepare for pregnancy. The menstrual cycle begins around menarche (11-15 years old) until menopause (age 43-51).
Menstruation occurs when a woman's body discards the monthly buildup of the lining of the uterus. The menstrual blood and tissue flows from a woman's uterus through the cervix and pass out through the vagina. This is often referred to as the "period," one of the code words I alluded to above.
Why is the menstrual cycle important for female runners?
As stated by Dr. Stacy T. Sims, "Women are not small men, especially when it comes to running." While many of the general training principles are the same for either sex, women deal with a much more complicated hormonal environment compared to men. 
Therefore, women have to be more concerned about how their bodies respond to training stimuli. With more knowledge and education, coaches can help train around the menstrual cycle for better training and greater athletic performances.
Missing a menstrual cycle is a signal that a possible dysfunction is occurring and it should be taken very seriously. This should not be ignored as females who miss their menstrual cycles are at risk for some of the following:
● Decreased immunity towards illnesses
● Decreased cardiovascular health
● Decreased bone mineral density
● Increase in musculoskeletal injuries
How does the menstrual cycle affect running?
Every woman is a bit different when it comes to their menstrual cycle. Some women may feel have minimal effects, while others may experience fatigue, cramps, bloating, and overall difficulty in completing workouts.
A woman's hormones fluctuate continuously throughout the menstrual cycle. There are two primary phases that occur during the menstrual cycle: the follicular phase, which begins at the onset of menstruation, and the luteal phase, which begins at the onset of ovulation and continues until the menstruation begins, thus restarting the cycle. Each phase lasts approximately 14 days. 
During the follicular phase, women are typically able to do their most difficult workouts. The testosterone levels rise at the beginning of the follicular phase. Women typically are able to train harder, recover more quickly, and feel more refreshed and energetic during training.
Estrogen levels rise and peak, just before ovulation. The rise in estrogen produces a sudden release of luteinizing hormone, which prompts ovulation. A day or two later the luteal phase begins. 
During the luteal phase or second half of the menstrual cycle, progesterone levels begin to rise. Progesterone After ovulation, estrogen levels drop before rising again toward the middle of the luteal phase. If fertilization does not occur, the levels of estrogen and progesterone quickly drop. The luteal phase ends with the start of menstruation and the cycle repeats.
For many women, training may seem more difficult during the luteal phase. Sleep and concentration may be lacking. The spike in progesterone can lead to an increase in body temperature and breaths per minute due to the loss of water and electrolytes. This means that many women resting heart rates will be increased during this phase.
Women may typically feel lethargic during this phase and lighter to moderate training may aid in recovery. 
Male (Some Female) Coaches and The Taboo
All female runners go through their menstrual cycle but few hardly ever talk about it with male coaches. Male coaches need to have frank discussions with their female athletes regarding the effects that their menstrual cycle can have on training and performance.
I believe that all female athletes should track their menstrual cycles. It can be as simple as having an athlete log their phases and perceived feelings in a notebook. The journal can be completely private but the athlete needs to become aware of how their body exactly works to maximize their training.
Many male coaches seek to actively avoid the conversation for the fear of feeling uncomfortable. But is it not about the coach being uncomfortable, but more so, how comfortable the athlete feels discussing it with the coach?
Every female athlete should feel comfortable telling a coach that she is feeling a certain way in practice or at a meet. It should be a small thing. I believe that it should be treated the same way as an athlete that is expressing that they are fatigued or feeling nauseous. You work around it.
I believe ignorance about female physiology is one of the primary reasons that discussions about the menstrual cycle are considered taboo. Many female athletes that are coached by males, particularly in junior high and high school, don't particularly understand human anatomy, and better yet how the menstrual cycle affects their training. It is our job to educate those who do not know.
But how can one educate one about a subject that they are not well versed about? Simple answer: They can't. The blind cannot lead the blind. How is a coach supposed to bring out the best in their female athletes if they have no idea what is going on with their athletes' bodies?
Each male coach must take it upon himself to seek out information and knowledge about female physiology. As stated earlier, "Women are not small men, especially when it comes to running."
Male coaches must be willing to have discussions with female athletes about the menstrual cycle and its effect on performance and training. Coaches must become educated about the effects of the menstrual cycle on performance and training.
The coach must be willing to put themself in a position to get the most from the athlete. I've realized that in order to get the most from the athlete, there has to be a relationship built on trust. For me, this means that the athlete has to trust me as much as I trust them.
If male coaches are uncomfortable having this conversation or don't fully understand the menstrual cycle, then it is that coach's responsibility to bring in someone who does. Being uncomfortable is not an excuse to feign ignorance. The coach should still be aware of the physiology of the female body.
Many female athletes may not feel comfortable speaking about the topic. So as male coaches, our job is to build that relationship of trust and transparency. It may also involve bringing parents or another adult female into the conversation.
With younger females, it is probably a conversation that the male coach is having with the parents and the athlete, as some parents may not feel it is appropriate with a male coach to be having that conversation with their daughter.
However, this discussion must be had in some capacity with the female athlete and parents. It is a disservice to a female athlete when their coach is not knowledgeable about the menstrual cycle and/or afraid to have a discussion about the topic due to fear of embarrassment.
How coaches can use the Menstrual Cycle to better train female runners?
Menstrual health may be a huge indicator of energy availability. Low energy environment can lead to fatigue. This means that female athletes need to make sure that they are taking in enough calories, liquids and getting adequate recovery during different phases of their menstrual cycle.
Training too much or too hard along with inadequate recovery will lead to overtraining which will lead to injury. Throughout my years of coaching, I have seen numerous girls overtraining and not getting enough calories. I have always said it is not if they will get injured but when they will get injured.
If a runner feels bad, delay the workout. Let the runner recover and rest. That will help to build their confidence, a relationship of trust with the coach and that athlete will perform better when that athlete does the workout.
As coaches, we need to use the information about the menstrual cycle to get the most out of our female athletes. I have only touched on a few specifics in this post but as coaches, we owe it to ourselves and athletes to become more educated if we truly care about our athletes and to help the advancement of the sport. 
Let's make our athletes Victors, not Victims.
1. American Family Physician; Julia Hobart, MD & Douglas Smucker, MD
2. Dr. Stacy Tims, "ROAR- women are not small men (2016)"
3. Professor Allan E. Herbison, Front Neuroendocrinol. 2020 Apr
4. American Psychiatric Association Diagnostic and Statistical Manual of Mental Disorders