The Female Athlete - Clinical Tree

History of Women In Sports

Throughout history, women have participated in sports at much lower rates than men.
Still, Egyptian temple wall illustrations depict women playing ball games in 2000 BCE. The first recorded women’s athletic competition was the Heraean Games in the sixth century BCE held in the original Olympic stadium. The women of indigenous tribes in the Americas participated in multiple sports until European colonization and forced assimilation into Western culture. And the first women’s professional sports team was the black women’s baseball team, the Dolly Vardens, established in 1867.
Title IX was passed in 1972, which stated that no person in the United States shall, on the basis of sex, be excluded from participation in, be denied the benefits of, or be subjected to discrimination under any educational program or activity receiving federal funding.
US high school sport participation has improved since the introduction of Title IX. In 1971–1972, 7.4% of athletes were girls, compared with 42.9% in 2018–2019.
Centers for Disease Control and Prevention (CDC) data from 2019 showed that 54.6% of high school girls played one or more sports in the previous year compared with 60.2% of boys. Racial disparities in sport participation also exist, with the following breakdown of self-identified race and percent participating in one or more sports: Asian 46.5%, Hispanic or Latino 51.6%, Black or African American 56.1%, and White 62%.
Women’s participation in the modern Olympic games has improved from 2.2% of athletes in the 1900 Paris games to 45.2% of athletes in the 2016 Rio games.
Sociocultural determinants that improve female sports participation include parental support (may take form of verbal support, a rule to participate in sport, or role modeling), higher socioeconomic status, higher rates of sibling sports activity, and higher parental education level.
Female participation in sports increased when the sport was perceived to be fun, involved friends, and had familial and school support through feedback and role modeling.
Guidelines regarding transgender women participating in sport have varied depending on the sport governing body and may include duration of hormone therapy, legal recognition of their gender and time lived as their gender, and testosterone levels. Ultimately these guidelines do not always agree and may not always be rooted in evidence-based medicine. This presents a significant barrier to transgender women being able to participate in many competitive sports.
There remains a significant gender disparity in coaching, with only 11% of accredited coaches at the Rio 2016 Olympic games being women. Women’s coaches at the collegiate level have actually declined since the introduction of Title IX.
Gender disparity in sports persists across multiple streams, including percentage of athletic directors and administrators, team physicians, head athletic trainers, professional sports pay, and media representation of women in sports, among others.
Racial disparities for women of color in sports are essentially multiplied in addition to the gender disparities faced. These issues can significantly affect the role modeling and support that are necessary to encourage young female athletes in their sport participation.

Benefits And Risks Of Sports Participation For Women

Studies show that women who participate in sports as adolescents enjoy an overall reduction in all-cause mortality and a significant reduction in cancer rates continuing into adulthood.
Adolescent sports participation correlates with increased bone density, which extends into middle-age for women who previously participated in sports in comparison with those who did not.
High school and collegiate girls who participate in sports every day have a decreased body mass index (BMI) and increased cardiorespiratory fitness compared with female nonathletes.
Measures of mental health and well-being in terms of self-esteem, depression, and suicidality are all positively affected by sports participation in high school and college athletes in general, but this is not correlated with gender, race, or ethnicity.
Studies have found overwhelming positive benefits to cognitive abilities, academic performance, and education levels relating to participation in high school and collegiate athletes. And in older adults, regular physical activity lowers rates of cognitive decline.
Even controlling for race, mother’s education, age, number of relationships, and alcohol consumption, risk of bullying, property violence, sexual abuse, rape, and violent contact is lower among female athletes than among nonathletes.
Nonaccidental harms such as bullying and physical and sexual abuse have higher rates among para-athletes when compared with able-bodied athletes. Female para-athletes may have higher rates of sexual violence than their male counterparts.
Noting that sexual behavior in female athletes is complex, overall, most studies suggest that there are positive effects from sports participation. This includes lower rates of sexual activity, pregnancy, and sexual risk-taking in high school and collegiate girls who participate in sports than in boys and nonathletes.
High school and collegiate female athletes exhibit lower rates of smoking, marijuana use, and other illicit substance use than nonathletes. However, they may have increased rates of smokeless or chewing tobacco use and nonprescription opioid use.
Alcohol use is much higher in the adolescent athlete population regardless of gender or race.

Physiology

Girls achieve physiologic maturity quicker than boys, thus achieving earlier peak height velocity (11.5 years [y] vs. 13.5 y) and skeletal maturity (13.5 y vs. 14.3 y). Along with hormonal changes at the time of puberty, there are many physiologic differences between male and female athletes.

Tables 12.1 and 12.2 outline the effects of estrogen and progesterone.

Table 12.1

Effects of Estrogen

System	Effect
Cardiovascular	↑ in thrombosis ↓ total cholesterol ↓ low-density lipoprotein (LDL) levels ↑ high-density lipoprotein (HDL) levels Vasodilates vascular smooth muscle ↑ blood pressure
Endocrine	↑ intramuscular and hepatic glycogen storage and update Glycogen sparing (↑ lipid synthesis, ↑ lipolysis in muscle, and ↑ utilization of free fatty acids) ↑ insulin resistance and ↓ glucose tolerance Deposition of fat in the breasts, buttocks, and thighs
Bone Metabolism	Facilitates uptake of calcium into bone
Neurologic	Cognitive function and verbal memory in postmenopausal women

Table 12.2

Effects of Progesterone

System	Effect
Thermoregulation	↑ core body temperature of 0.3°C–0.5°C
Respiratory	↑ minute ventilation
Respiratory	↑ ventilatory response to hypoxia and hypercapnia
Metabolic	Fluid retention
	↑ dependence on fat as a substrate
	Induce peripheral insulin resistance

Cardiology

Female athletes typically have a slightly higher resting heart rate (HR) and a lower systolic blood pressure (BP) than male athletes. With exercise, female athletes exhibit a lower absolute change in their systolic BP.
Although males typically have larger hearts at baseline, both male and female athletes demonstrate physiologic cardiac hypertrophy in response to training. Of note, exercise in black female athletes is associated with greater left ventricular hypertrophy and repolarization changes than comparative white female athletes.
The mechanism for hypertrophy may be different in females compared with testosterone-driven muscle hypertrophy in males. Females have a higher Ca ²⁺ /calmodulin-dependent kinase (CaMK) and protein kinase B/glycogen synthase kinase-3-beta (AKT/GSK-3) pathway signaling, as well as increased fatty acid metabolism, which may contribute more to female-specific physiologic cardiac hypertrophy.
Pathologic cardiac hypertrophy and arrhythmias are less common in female athletes and considered secondary to estrogen’s protective cardiac effects against harmful remodeling.
Gender differences in cardiac functioning and contribution to maximal oxygen consumption (VO ₂ max) may be more related to the larger size of male hearts that have greater stroke volume compared with smaller female hearts.

Pulmonology

Beginning at around 2 years of age, male lungs are larger than female lungs even when normalized to height and length.
In addition, females have considerably smaller airways, which can contribute to expiratory flow limitations.
On approaching maximal exercise, females increase their end expiratory lung volumes back toward resting, hyperinflating their lungs in response to these expiratory flow limitations. Simultaneously, higher end inspiratory lung volumes are required to maintain tidal volume. Ultimately, the intensity of breathing is greater in females—approximately twice as high at maximal exercise.
The prevalence of arterial oxyhemoglobin desaturation is higher in females than in males because of smaller lung volumes, smaller airways, lower resting diffusion capacity, and lower maximal expiratory flow rates.
Interestingly, females experience less exercise-induced diaphragmatic fatigue than males.

Metabolism, Nutrition, and Hydration

17 β-Estradiol promotes lipid oxidation during endurance exercise, and female athletes have been shown to have a greater dependence on lipid oxidation during endurance events. In addition, 17 β-estradiol promotes hepatic glycogen sparing.
This enhanced capacity of lipid oxidation, as well as a greater ability to maintain plasma glucose, may account for the ability of female athletes to outperform male athletes at very high distances.
Females have a lower leucine oxidation rate at rest and during exercise, which accounts for their lower protein requirements.
There is some evidence that female athletes do not obtain the same benefits from traditional carbohydrate loading compared with male athletes, and in fact need to ingest a proportionally higher amount of carbohydrates in order to gain the same effects.
Lower ferritin and total body iron tend to be associated with higher oxidative stress. Female athletes are frequently shown to have higher levels of reactive oxygen metabolites and lower iron stores than their male counterparts.
Throughout the menstrual cycle, from early follicular phase to luteal phase, total body water in females can increase by as much as 2 L. Females have been shown to have lower urine osmolality than do males at rest, with daily activities and with exercise, most likely because of differences in arginine vasopressin (AVP) concentrations.
Female athletes do not sweat as much as male athletes do, although they do sweat over a greater proportion of their body. In addition, studies have shown that females tend to overconsume water in relation to their body size and metabolic rate.
A study evaluating the relationship between blood lactate and cortical excitability during exercise revealed that females exhibited a significantly greater improvement in excitability of the primary motor cortex in response to increased lactate levels; this was attributed to the excitatory role of estrogens on the cerebral cortex.

Muscles/Ligaments/Tendons

Female athletes have been shown to have a similar composition of muscle fibers and enzymatic activity as their male counterparts do when involved with similar sports and activities; however, female muscle fibers are smaller.
Female athletes are able to achieve significant strength gains with training, but they cannot achieve the same strength levels or hypertrophy as a similarly sized and trained male athlete because of the difference in testosterone.
Before puberty, both boys and girls have similar strength and joint laxity. At puberty, estrogen contributes to increased joint laxity and possibly increased muscle strength in girls, whereas testosterone contributes to increased muscle strength and hypertrophy in boys.
Some of the increased injury risk seen in female athletes after the age of puberty is attributed to lax joints and strength imbalance caused by this hormonal change.
Certain studies have shown lower collagen synthesis in tendons of combined oral contraceptive users, although not all studies have reported differences in tendon properties across the menstrual cycle.

Gastrointestinal Symptoms

The incidence of gastrointestinal symptoms and complaints is higher in female endurance athletes.
In addition, studies have revealed a higher incidence of gastrointestinal ischemia in female athletes than in male athletes; however, the underlying pathophysiology remains unknown.

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here