65. | Manual of Rheumatology and Outpatient Orthopedic Disorders (LB Spiral Manuals)

Chapter 58 The Female Athlete

Manual of Rheumatology and Outpatient Orthopedic Disorders

Chapter 58 The Female Athlete

Lisa R. Callahan and Jo A. Hannafin

Physiologic considerations
Female athlete triad
Orthopedic issues
Medical considerations
Nutritional concerns
Equipment and shoes

Regular exercise has been shown to decrease the risk for multiple diseases, including coronary heart disease, hypertension, osteoporosis, obesity, depression, and some reproductive cancers. The U.S. Preventive Services Task Force and the Office of Disease Prevention and Health Promotion have emphasized that as the population ages (with women comprising the majority of the elderly), physical activity and fitness must be viewed as a health goal priority. Additionally, studies have demonstrated that girls who play high school sports are less likely to have an unwanted pregnancy or use drugs, are more likely to graduate from high school, and have lower levels of depression. Clearly, encouraging an active life-style among women is critical to their long- term health. Although many aspects of physical activity are similar in both male and female populations, some issues require special consideration in the female athlete.

I. Physiologic considerations

Body structure
1. Skeletal growth reaches its peak at an earlier age in girls (10.5 to 13 years of age) than in boys (12.5 to 15 years of age). Skeletal maturity occurs by age 17 to 19 in girls, and by age 21 to 22 in boys.
2. The female pelvis is wider than the male pelvis, causing an increased quadriceps (Q) angle, which commonly contributes to anterior knee pain (also called patellofemoral syndrome).
3. Women have thinner, lighter bones than their male counterparts, which may predispose them to osteoporosis and stress fractures.
Body composition
1. In general, women have approximately 10% more body fat than men do, and 60% to 85% of the total muscle cross-sectional area of men. Because muscle is more metabolically active than fat, women have on average a resting metabolic rate 5% to 10% lower than that of men.
2. The response to weight training, as measured by muscle hypertrophy and gains in strength, is similar in women and men.
3. The percentage of body fat can be estimated by a variety of methods ; ideal body fat composition varies with age and sex.
Cardiorespiratory system
1. Women have a smaller thoracic cage and heart size , resulting in a lower lung capacity and maximal cardiac output.
2. Maximum oxygen consumption (VO ₂ max) is lower in women, largely because of differences in body composition and oxygen-carrying capacity. VO ₂ max is similar in boys and girls before puberty.
Circulatory system
1. Women have a smaller blood volume, smaller iron stores, and lower concentrations of hemoglobin. These factors are associated with a lower oxygen-carrying capacity and also increase the risk for anemia.
2. Both male and female lite athletes tend to have lower levels of hemoglobin than their sedentary counterparts. This may be secondary to both a low dietary intake and exercise- related blood loss, such as occurs from the gastrointestinal tract .
Endocrine system
1. There is no evidence that the phase of the menstrual cycle influences athletic performance.
2. Female athletes may experience a wide array of alterations in the menstrual cycle, ranging from suppression of the luteal phase to amenorrhea. The latter is especially prevalent in athletes at risk for the female athlete triad (see section II ).
3. Pregnancy results in many physiologic changes, including increases in cardiac output, blood volume, and oxygen demand. There is a great deal of controversy surrounding exercise in the gravid athlete; the American College of Obstetrics and Gynecology has released guidelines that some researchers criticize as being more conservative than necessary. Much more research is needed to delineate safe volumes , types, and intensities of exercise in the pregnant athlete.

II. Female athlete triad

General considerations
1. The female athlete triad refers to the interrelatedness of three conditions: disordered eating , amenorrhea, and osteoporosis.
2. Traditionally, female athletes at risk were thought to be those whose activity emphasized leanness for aesthetic reasons (ballet, gymnastics), who associated a low body weight with improved performance (distance running), or those who were classified by weight (rowing, judo). However, girls at risk have been found in many other sports, including swimming, soccer, volleyball, and cycling.
Disordered eating
1. It is important that the clinician differentiates disordered eating from the eating disorders of anorexia nervosa and bulimia nervosa, which are psychiatric diagnoses with specific diagnostic criteria. Disordered eating is a much more common phenomenon , and restricting awareness to the extremes of anorexia and bulimia will result in failure to recognize girls at risk for the triad.
2. Disordered eating behaviors include the following:
  1. Food restriction.
  2. Fasting.
  3. Bingeing (which may or may not be followed by purging).
  4. Use of diet pills, diuretics, and laxatives.
3. Girls suffering from disordered eating are often
  1. Preoccupied by thoughts of food.
  2. Plagued by a distorted body image.
  3. Afraid that any weight gain is the equivalent of getting fat.
Amenorrhea
1. Primary amenorrhea is defined as the absence of menarche by the age of 16.
2. Secondary amenorrhea is the absence of three to six consecutive menstrual cycles in women who have experienced menarche.
3. It is believed that exercise in the setting of inadequate calorie consumption may contribute to an energy- deficient state, which may lead to amenorrhea.
4. In this setting, amenorrhea represents a hypo-estrogenic state, which can predispose to osteoporosis.
5. Exercise-related amenorrhea is a diagnosis of exclusion. Other causes of amenorrhea, such as pregnancy, must be considered before it is assumed that cessation of menses in an athlete is exercise-driven.
Osteoporosis
1. Osteoporosis refers to bone loss in addition to inadequate bone formation, which results in lower bone mass, increased skeletal fragility, and increased risk for fracture.
2. Premature osteoporosis occurring in the female athlete may be irreversible, even when treated with calcium supplementation, hormonal replacement therapy , and correction of amenorrhea.
3. Stress fractures may occur with more frequency and severity in female athletes at risk for the triad; although there are no current guidelines regarding screening, one should consider evaluation of bone density to screen for premature osteoporosis in an athlete identified as being at risk for the female athlete triad.

III. Orthopedic issues. Current knowledge suggests that most injuries sustained by athletes are sport-specific rather than gender-specific (see Chapter 22). However, several orthopedic issues of special concern in the female athlete deserve specific mention.

Anterior cruciate ligament (ACL) injuries
1. Epidemiologic data suggests that the incidence of severe knee injuries, especially ACL injuries, is higher in women than in men, particularly in the sports of soccer and basketball (threefold to fivefold increase).
2. The causes of increased ACL injuries are unclear. Factors thought to contribute to the higher rate of ACL injury are both intrinsic and extrinsic.
  1. Intrinsic factors
    1. Ligament size.
    2. Intercondylar notch dimensions.
    3. Muscular strength and coordination.
    4. Limb alignment.
    5. Hormonal influences.
  2. Extrinsic factors
    1. Shoe-floor interface.
    2. Level of skill and experience.
    3. Inadequate training and coaching.
Patellofemoral pain
1. Injuries to the patellofemoral joint are more common in women. Patellofemoral pain is often thought to be secondary to a variation in limb alignment ( miserable malalignment syndrome) consisting of a combination of increased anteversion of the femoral head, internal rotation of the femur, external rotation of the tibia, and foot pronation. Other anatomic features often blamed for patellofemoral pain include an increased quadriceps angle and hypermobility of the patella.
2. Patellofemoral pain should be differentiated according to whether the patella is hypermobile or tight (lateral patella compression syndrome). This distinction is important because treatment varies depending on whether the patella needs to be restrained (in the case of hypermobility) or loosened (in the case of tight lateral structures causing lateral compressive pain). In the case of the hypermobile patella, strengthening of the medial quadriceps (vastus medialis obliquus) aids in restraining the patella. In the patient with tight lateral structures causing lateral pull of the patella, stretching lateral structures, including the lateral retinaculum and iliotibial band , is recommended. A patellar tracking brace may be helpful in the patient with hypermobility of the patella but may actually exacerbate pain in the patient with lateral patella compression syndrome.
Shoulder pain
1. Adhesive capsulitis is an idiopathic inflammatory synovitis in the glenohumeral joint. It occurs three to seven times more frequently in women than in men. The cause is not well understood , but the clinical entity is frequently associated with other conditions, such as diabetes and menopause. Four distinct stages have been recognized, which reflect the degree of synovitis. The cornerstones of treatment include intraarticular steroid injection and a rehabilitation program to maintain strength and range of motion. Manipulation under anesthesia and arthroscopy may be required.
2. Impingement syndrome, an overuse injury to the rotator cuff, occurs frequently in both male and female patients . However, in women, causative factors are often related to underlying glenohumeral laxity. Increased capsular laxity requires an increase in rotator cuff activity, leading to overuse and impingement. Another factor, especially in the novice female athlete, is deconditioning and weakness of the upper extremity , which leads to rapid fatigue of the rotator cuff, particularly with overhead activity.
Stress fractures
1. Although stress fractures occur in both male and female athletes, they are clinically considered more common in female athletes, especially in certain sports such as running and gymnastics.
2. The tibia is the most common site of stress fracture for all athletes; the pelvis and metatarsals are frequent sites of fracture only in female athletes.
3. Variables related to the increased rate of stress fractures in women include the following:
  1. Menstrual irregularity/amenorrhea.
  2. Low bone mineral density.
  3. Training errors.
  4. Biomechanical alignment of the lower extremity.
  5. Decreased muscle strength in the lower extremity.
  6. Diet.
4. Evaluation of the female athlete with a stress fracture must include a careful menstrual history; loss of menses or any change in frequency or duration of the menstrual cycle requires further evaluation.

IV. Medical considerations. Achieving fitness through moderate exercise has been linked to lower risks for heart disease, hypertension, cancer, depression, and osteoporosis ”diseases that affect both women and men. General guidelines suggest that both women and men should be evaluated by a physician before embarking on an exercise program, especially after age 40. Although most medical considerations in the athlete are not gender-specific, a few issues are of special concern to those caring for the female athlete.

Osteoporosis. Moderate exercise may help to decrease the risk for osteoporosis, but exercise in the face of disordered eating and amenorrhea may contribute to premature osteoporosis. Low estrogen states are associated with an increase in urinary loss of calcium and a decrease in calcium absorption from the gastrointestinal tract, which lead to less calcium deposition in bone. In the female athlete, a stress fracture may be a warning sign of osteoporosis and warrants thorough evaluation. Additionally, illnesses such as hyperthyroidism (whether overt, subclinical, or iatrogenically induced by excessive replacement of thyroid hormone) are more common in the female population and may contribute to osteoporosis.
Rheumatologic disease. Most rheumatologic diseases, such as lupus, rheumatoid arthritis, and fibromyalgia, are reported to occur two to 10 times more frequently in women than in men. Often, the first manifestation of such an illness is mistaken for an athletic injury. The physician should be alert to this fact and should include rheumatologic disease in the differential diagnosis of musculoskeletal pain, especially in women.
Cardiovascular issues
1. Factors affecting the risk for sudden death include the following:
  1. Age and, to a small degree, cholesterol level (both sexes).
  2. Hematocrit, vital capacity, and glucose level (women only).
  3. Women who die suddenly are 50% less likely than men to have coronary artery disease.
2. In women, the incidence of false-positive findings on electrocardiographic exercise testing is much higher than in men; therefore, the use of additional imaging modalities is especially important in the female athlete suspected of having cardiovascular disease.
Exercise-related anemias. Anemia is more common in the female than in the male athlete, and in fact is more common in the female athlete than in the general population.
1. Dilutional pseudo-anemia is a natural dilution of hemoglobin that occurs as a result of the increase in plasma volume that is associated with regular exercise; it is often called sports anemia and is benign .
2. Exercise-induced hemolytic anemia may be secondary to macrocytosis (repetitive foot strike destroying red blood cells ) or to intravascular hemolysis. Although the iron loss is usually insignificant, this may become a clinically important entity in the lite female athlete.
3. Iron-deficiency anemia may be caused by gastrointestinal, sweat, urinary, or menstrual losses; impaired absorption; and inadequate intake. This type of anemia has an adverse effect on performance and requires treatment.
Infections. Physicians treating female athletes should be aware that certain types of infection, such as urinary tract and vaginal/ genital infections, are related to gender and anatomy and therefore are more common in the female population.

V. Nutritional concerns. Good nutrition is essential to athletic performance, and the basics of good nutrition are not gender-dependent. However, female athletes need to pay particular attention to a few special considerations.

Calcium
1. As mentioned previously, calcium is essential for bone health.
2. Recommendations for daily intake: 1,000 to 1,200 mg in premenopausal women, and 1,500 mg in postmenopausal women and adolescents.
Iron
1. See section IV.D.
2. Iron deficiency is often secondary to inadequate diet in addition to frequent losses, such as through menstruation.
3. A thorough evaluation is warranted before iron supplementation is prescribed.
Other dietary insufficiencies. Female athletes may have an inadequate intake of total calories , protein, and fat in efforts to avoid weight gain. Such dietary inadequacies are known to contribute to poor bone health and are thought to contribute to increased rates of certain injuries and possibly to decreased rates of healing. Extreme restriction of intake may not only affect performance but also have negative effects on health, similar to those seen in the patient with anorexia nervosa.

VI. Equipment and shoes

Equipment. Only recently has the athletic equipment industry begun to design exercise equipment intended for use by female athletes. In developing and choosing equipment, the physiologic differences between women and men mentioned briefly at the beginning of this chapter should be kept in mind. These factors should influence the future design of equipment such as bicycles, skis, racquets, and weight machines.
Shoes. A woman 's foot is different from that of her male counterpart in both shape and size. It is only recently that shoe manufacturers have begun to take such factors into consideration, which has resulted in greatly improved technology that is specific to the female athlete's anatomy and biomechanics as well as specific to the sport.

Bibliography

Agostini R. Medical and orthopedic issues of active and athletic women. Philadelphia: Hanley & Belfus, 1994.

Agostini R, et al. The athletic woman. Clin Sports Med 1994;13:2.

Warren M, Shangold M. Sports gynecology: problems and care of the athletic female. Cambridge, MA: Blackwell Science, 1997.

Books@Ovid
Copyright 2000 by Lippincott Williams & Wilkins
Stephen A. Paget, M.D., Allan Gibofsky, M.D., J.D. and John F. Beary, III, M.D.
Manual of Rheumatology and Outpatient Orthopedic Disorders

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