Advancing health through science, education and medicine

Current Comment Fact Sheets

ACSM offers a wealth of credible health and fitness information to individuals with an interest in sports medicine and exercise science. Our Current Comment fact sheet series offers expert perspectives -- often that of ACSM members -- on trendy or controversial topics in the field. Click the fact sheet title below to download a print-quality PDF.

ACSM grants permission to reprint Current Comments contingent upon material being reprinted in entirety without alteration. Proper credit must also be given by citing the name as follows: "Reprinted with permission of the American College of Sports Medicine, ACSM Current Comment Anabolic Steroids."

Alcohol and Athletic Performance

The effects of alcohol can depend on the amount consumed, the environmental context, and on the individual. Daily consumption of up to four drinks may have a protective effect on the cardiovascular system. Nonetheless, people most commonly drink for alcohol’s anxiolytic (stress-reducing) property. Conversely, alcohol has a wide spectrum of negative effects, from societal to physiological, accounting for approximately 100,000 deaths yearly in the United States. From a physiological perspective, two situations draw special attention for the fitness-oriented individual who consumes alcohol. Acutely, alcohol can cause negative effects on motor skills and physical performance. Chronically, alcohol abuse may eventually impede physical performance; individuals diagnosed with alcohol dependence have displayed varying degrees of muscle damage and weakness. Furthermore, alcohol abuse is at least as prevalent in the athletic community as it is in the general population; the vast majority of athletes have begun drinking by the end of high school.
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Exercising with Allergies and Asthma

Allergies and asthma can make regular exercise and physical activity difficult, unpleasant, and sometimes impossible. However, when properly managed, these conditions should not affect your ability to exercise recreationally or even competitively. Physician evaluation and treatment, understanding what causes or worsens your allergies and/or asthma, and knowing how to exercise safely and effectively will enable you to exercise without limitation.
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Anabolic Steroids

The use of drugs to enhance strength and endurance has been observed for thousands of years. Today, individuals, including adolescents, continue to employ a variety of drugs, such as anabolic steroids, in hope of improving their athletic performance and appearance. Anabolic steroids are not mood altering immediately following administration. Instead, the appetite for these drugs has been created predominantly by our societal fixations on winning and physical appearance.
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Athletes and Pesticides

Pesticides (herbicides, insecticides and fungicides) are commonly used on athletic facilities. The application of pesticides is usually at the discretion of the gardeners and/or facilities managers, and there are state and federal regulations that require certification of people who make pesticide application on school grounds. Because pesticides are registered with the Environmental Protection Agency (EPA), it is commonly assumed that they are completely safe. However, the EPA states that all pesticides are toxic to some degree, meaning that they can pose a risk. Further, the EPA urges that appropriate safety precautions be taken and that it should never be assumed that a pesticide is harmless. It is important that those responsible for pesticide treatment be knowledgeable about their use, restrictions, and warnings. Care should be taken, especially at facilities where contact sports are played.
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Caffeine and Exercise

Caffeine may be the most widely used stimulant in the world. It is found in a variety of plants, dietary sources (including coffee, tea, chocolate, cocoa, and colas), and non-prescription medications. The average caffeine consumption in the USA is approximately 2 cups of coffee per day (200 mg); 10% of the population ingests more than 1000 mg per day. Caffeine is a socially acceptable, legal drug consumed by all groups in society. Caffeine is often referred to as a nutritional ergogenic aid, but it has no nutritional value. Ingested caffeine is quickly absorbed from the stomach and peaks in the blood in 1-2 hours. Caffeine has the potential to affect all systems of the body, as it is absorbed by most tissue. The remaining caffeine is broken down in the liver and byproducts are excreted in urine.
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Ankle Sprains and the Athlete

Reports estimate that 25,000 Americans suffer from an ankle sprain each day. Ankle sprains account for almost half of all sports injuries and are a common reason why athletes take time off from activities. Accurate diagnosis is critical, as some studies suggest that 40 percent of ankle sprains are misdiagnosed or poorly treated leading to chronic ankle pain and disability. Self-education is important in order to decrease the risk of this disabling complication.
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Childhood Obesity

The global presence of overweight and obesity has reached epidemic levels over the last few decades, most notably in the United States. From 1980 to 2004, the prevalence of overweight and obesity in children more than tripled, rising from 5 to 15 percent. Children whose parents are overweight or obese have a greater chance of being overweight and obese themselves. Overweight children and adolescents are more likely to become obese adults. As a result, we have observed an increase in the diseases (“comorbidities”) that had traditionally been viewed as “diseases of aging” which are now appearing in children: type 2 diabetes, high cholesterol, hypertension, cardiovascular disease, sleep apnea, and orthopedic problems. In addition, psycho-social problems such as low self-esteem and teasing from peers may cause life-long damage to children. There is now a generation of children who may not outlive their parents due to overweight and obesity unless we reverse this trend.
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Chronobiological Effects on Exercise

It has long been known that most physiological variables demonstrate predictable, rhythmic variability within the 24-hour day. For example, body temperature is lower during the early morning hours and progressively increases during the waking hours. The fluctuation of any variable within the 24-hour day is described as a “circadian” rhythm. If not measured at equal increments throughout the 24- hour day, changes in a variable are best described as “time of day” or “chronobiological” variation. Because we do not exercise during normal sleeping hours, we will focus on chronobiological variation in exercise performance during the segment of the day in which activity typically occurs, 8:00 AM - 8:00 PM.
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Cocaine Abuse in Sports

The abuse of recreational drugs, both licit (e.g., alcohol and nicotine) and illicit (e.g. cocaine, marijuana) by athletes far outweighs their abuse of performance-enhancing drugs (e.g. anabolic steroids). The situation is not unique to athletes; many factors contribute to recreational drug use. They include age, genetics, family influences, peer pressure, education and mental health factors. The abuse of cocaine in sports first attracted national attention in 1986 with the cocaine-related sudden deaths of basketball star Len Bias and football star Don Rogers. The use of cocaine at the collegiate athlete level peaked in the mid-1980s at about 17 percent, and fell dramatically over the ensuing decade to less than two percent. While many factors are at play motivating an athlete to use cocaine, several points are particularly noteworthy. First, cocaine is generally not used to enhance performance. Second, athletes are thought to be vulnerable to recreational substance abuse because of some combination of the following variables: fame, fortune, free time and a feeling of invincibility.
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Corporate Wellness

Enlightened companies have sponsored sports teams and, in some instances, have provided sports fields at their worksites throughout much of the twentieth century. Such initiatives were viewed mainly as a method of building a team spirit and increasing employee morale. However, the proportion of employees who were actively involved in worksite sports teams was relatively small. Brief calisthenic breaks for all employees were introduced at some European worksites as early as the 1960s, and it was claimed that such programs enhanced the performance of both physical and mental well-being. In the mid-1970s, the Canadian government launched a similar plan, providing taped music and written instructions to volunteer exercise leaders in many large office buildings. Unfortunately, the concept that an entire working group could cease operations for 7-8 minutes of exercises twice each work day did not fit well with many modern industrial and business operations. Nevertheless, the interest of the U.S. and Canadian governments in the promotion of health-related fitness developed rapidly during the 1970s. Government agencies still perceived the worksite as a favorable location for program delivery. Suggested advantages relative to community-based fitness programming included a discreet population of manageable size, with established channels of administration and communication, a strong potential for the recruitment of volunteer assistant exercise leaders, and peer support of those who were beginning fitness programs for the first time. Moreover, the introduction of a fitness program was seen as an important first step in the development of a healthy overall working environment ranging from a wise choice of canteen foods to a smoke-free worksite. Above all, no travel time was needed in order to attend a worksite fitness program, so that the usual excuse of the sedentary person (lack of time) was overcome.
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Dehydration and Aging

Water serves a vital role in the everyday operation of cells within the body. The maintenance of water balance is essential for health and is determined by a sophisticated scheme that balances water input (drinking) and water output (perspiration, urine) from the body. Specific mechanisms interact to control thirst, drinking behavior, and the output water from the kidney when the body is faced with a water deficit. However, restoring body water balance following dehydration ultimately depends on mechanisms that regulate fluid intake or drinking. Despite these sophisticated defense mechanisms, the restoration of water balance following dehydration is usually slow and incomplete; a problem termed “involuntary dehydration.” Thus, even healthy young adults should be advised of the benefits of complete water replacement following dehydration. More importantly, it has become increasingly clear that the ability to regulate fluid balance in response to fluid deprivation or dehydration is compromised in older individuals. Decreased ability to regulate water balance can adversely affect the aging population, leading to increased risk of dysfunction, morbidity, or mortality. In addition, these problems in body fluid regulation are often exacerbated by the presence of other chronic diseases associated with aging, such as hypertension or cerebrovascular disease. As such, the aging population is considered at greater risk for developing dehydration and any associated complication.
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Dehydration and Estrogen

Changes in body water content can exert profound effects on physiological function and performance. For example, dehydration limits sweating and heat dissipation, causing increased core temperature, reduced exercise tolerance and increased risk for heat-related injury. Sophisticated mechanisms have evolved to maintain body fluid volume and composition despite sudden fluxes in water intake or loss. These regulatory mechanisms involve reflexes within the blood vessels, brain and intestines that act to modify rates of fluid intake and fluid output. Dehydration is a normal physiological state following prolonged exercise in the heat, which leads to the loss of water and increase of sodium in the blood. This state leads, in turn, to thirst, fluid intake and sodium/water retention by the kidneys. There are a number of “fluid retention” hormones that exert a profound control over this fluid regulatory system. Hormones are substances in the body that act to promote certain activity by specific organs. The fluid regulatory hormones act primarily on the brain and kidney to control both intake and output of water and sodium. The most important hormone of this type is the antidiuretic hormone, which responds rapidly to changes in body water status, and is responsible for controlling the rate of water retention by the kidneys. To complicate matters, antidiuretic hormone regulation maybe modified by a variety of factors, one of which may be the female sex hormone estrogen.
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Eating Disorders

Many student-athletes face a difficult paradox in their training regimes. They are encouraged to eat to provide the necessary energy sources for performance, yet they often face self- or team-imposed weight restrictions. Emphasis on low body weight or low body fat may benefit performance only if the guidelines are realistic, the calorie intake is reasonable, and the diet is balanced. The use of extreme weight-control measures can jeopardize the health of the student-athlete and possibly trigger behaviors associated with defined eating disorders. The National Collegiate Athletic Association (NCAA) studies show that at least 40 percent of member institutions reported at least one case of anorexia or bulimia in their athletic programs. Although these eating disorders are much more prevalent in women (approximately 90 percent of the reports were in women's sports), eating disorders also occur in men.
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Endurance Exercise Following a Stroke

Approximately 750,000 people in the United States experience a stroke or cerebrovascular accident (CVA) each year. Strokes are the third leading cause of death (after heart disease and cancer) in the United States and the leading cause of disability in adults. There are an estimated three million stroke survivors in the US; the combined direct and indirect costs of stroke are estimated at an annual $30 billion. Because of the similarities between coronary artery disease and ischemic stroke, it is not surprising that many of the risk factors for the two diseases seem to overlap. In particular, high blood pressure, smoking, poor blood lipid levels, elevated blood glucose and diabetes mellitus, and excessive alcohol consumption increase stroke risk. A variety of studies have also indicated that increased levels of physical activity are associated with decreased incidence of stroke. With respect to physical function following a stroke, approximately 14 percent of stroke survivors achieve full recovery and need no long-term rehabilitation. But half the survivors experience severe long-term effects such as partial paralysis. Between 25 and 50 percent need at least some assistance with the activities of daily living. It is also apparent that after a stroke, individuals may be intolerant of activity. The elderly, who comprise the majority of stroke survivors, are especially at risk for this intolerance. Such intolerance is likely due to several factors, such as bed-rest-induced deconditioning, the presence of pre-existing cardiovascular dysfunction, and/or increased energy cost during walking. Indeed, the motor effects of stroke can make the energy cost of walking up to two times higher than normal. These factors can conspire to create a vicious cycle of further decreased activity and greater activity intolerance, leading to even poorer cardiovascular conditioning. This is especially troubling given the prevalence of cardiovascular disease risk factors in this population; factors that might be modifiable with exercise training.
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Energy Expenditure in Different Modes of Exercise

One of the primary goals of an exercise program is to develop and maintain cardiorespiratory fitness. Many people engage in aerobic activities to improve their health status, reduce disease risk, modify body composition and improve all around physical fitness. It is important to select a mode of exercise that uses the large muscles of the body in a continuous, rhythmical fashion, and that is relatively easy to maintain at a consistent intensity. It is interesting to note that not all modes of exercise are comparable in terms of energy (caloric) expenditure. However, several factors, in addition to energy expenditure, should be considered when selecting an exercise mode.
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Exercise and Shoulder Pain

The human shoulder is an intricate system of bones, joints, connective tissues and muscles that place the arm and hand in a position that allows them to function. It derives its stability from a group of four small muscles (known as the rotator cuff) and another five muscles that stabilize the scapula (shoulder blade) and guide the entire shoulder joint along the rib cage during arm motions. Some experts state that the upper extremities can assume more than 1,600 positions in three-dimensional space at the shoulder joint. When working properly, the shoulder makes activities like throwing, hammering, shoveling, raking, painting, climbing, lifting, swimming and waving possible. A painful shoulder can make routine activities like brushing your teeth, bathing, dressing, sleeping, and combing your hair extremely difficult. Chronic shoulder pain (lasting more than a few weeks to a few months or more) is the most common upper extremity problem in recreational and professional athletes. According to the Centers for Disease Control and Prevention (CDC), approximately 13.7 million Americans sought medical care for shoulder pain in 2003 alone.
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Exercise and the Common Cold

A cold is an inflammation of the upper respiratory tract caused by a viral infection. The common cold is probably the most frequently occurring illness in humans worldwide. More than 200 different viruses cause colds, and rhinoviruses and coronaviruses are the culprits 25-60 percent of the time. Rhinovirus infections often occur during the fall and spring seasons, while the coronavirus is more common during the winter. The U.S. Centers for Disease Control and Prevention estimates that over 425 million colds and flus occur annually in the United States, resulting in $2.5 billion in lost school and work days, and in medical costs. The average person has two or three respiratory infections per year. Young children suffer from six to seven annually.
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Exercise and the Older Adult

By the year 2030, the number of individuals 65 years and over will reach 70 million in the United States alone. Those 85 and older will then be the fastest-growing segment of our population. We must determine the extent and mechanisms by which exercise and physical activity can improve health, functional capacity, quality of life, and independence in this population. Current evidence clearly indicates that participation in a regular exercise program is an effective way to reduce and/or prevent a number of the functional declines associated with aging. Older adults have the ability to adapt and respond to both endurance and strength training. Aerobic/endurance training can help to maintain and improve various aspects of heart and lung function and cardiac output, and such exercise can enhance endurance. Strength/resistance training will help offset the loss in muscle mass and strength typically associated with aging, thereby improving functional capacity. Also important, reduction in risk factors associated with disease (heart disease, diabetes, osteoporosis, and so on) will improve health status and contribute to an increase in lifespan. Together, these training adaptations will greatly improve the functional capacity of older men and women, therefore improving their quality of life and extend independent living.
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Exercise and Age-Related Weight Gain

Approximately one third of the U.S. adult population is overweight. The Year 2000 Objectives call for reducing the prevalence of overweight to 20 percent; thus weight control has become an important public health goal. The most commonly reported method of weight loss is dieting. However, the long-term success rate of this method is quite poor. Indeed, only about ten to 30 percent of those who lose weight by reducing calories maintain their full weight loss over time. Exercise may be associated with better long-term weight control than dieting alone, but the influence of regular physical activity on weight regulation is complex. Although numerous experimental studies have documented the positive effect of exercise training on body weight and fat stores, far less is known about how regular exercise affects attained weight and the risk of weight gain in the general population. What few longitudinal data there are suggest that regular physical activity may be useful in minimizing age-related weight gain or reducing the risk of substantial weight gain, rather than in actually promoting weight loss. Nonetheless, primary prevention of substantial weight gain with age may be a more efficacious public health strategy for reducing the prevalence of obesity and obesity-related morbidity and mortality in the United States.
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Exercise during Pregnancy

Exercise and physical fitness have dramatically gained in popularity over the past several years, and have assumed important roles in the lives of many women. Physical activity and reproduction are normal parts of life, and for normal healthy women, combining regular exercise and pregnancy appears to benefit both mother and baby in many ways. Thus, a healthy woman with a normal pregnancy may either continue her regular exercise regimen, or begin a new exercise program. The American College of Obstetrics and Gynecology (ACOG), as well as the American Society for Obstetrics and Gynecology (ASOG), recommends that normally healthy pregnant women may continue an already-established exercise regimen.
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Exercise for Persons with Chronic Obstructive Pulmonary Disease (COPD)

Chronic Obstructive Pulmonary Disease (COPD), such as emphysema, chronic bronchitis and asthma, is defined by the American Thoracic Society as a condition characterized by airflow obstruction that reduces the ability to sufficiently empty the lungs. The incidence of COPD is presently increasing in the U.S., with an estimated 16.5 million people now suffering from shortness of breath and the disabling effects of this disease. Lack of exercise contributes to disability in COPD. Exercise training is a major component of pulmonary rehabilitation programs today and is an established safe and effective intervention for improving physical capacity and quality of life. Aerobic exercise (riding a stationary bike or walking) and resistance exercise (lifting a light weight with the arms or legs) can help restore and maintain functional independence in COPD.
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Exercise-Induced Asthma

The terms “exercise-induced asthma” (EIA) and “exercise-induced bronchospasm” (EIB) are used synonymously to describe acute lung airway narrowing occurring during and/or after physical activity. EIA is considered a more inclusive term. The bronchospastic response is thought to result from a summation of specific events, including smooth muscle contraction of the airway, bronchial mucosal edema, and mucus plug formation. The pathogenesis of these events is associated with the generation of inflammatory mediators including leukotrienes, prostaglandins, and other immune system factors from airway mast cells, epithelial cells, and macrophages interacting with in-situ hormonal components of the lungs.
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Exercise in Health Clubs

Participation in regular physical activity is an important way to reduce the risk of a variety of degenerative diseases. It is comparable in magnitude of importance, but opposite in direction, to smoking, high blood pressure, elevated blood cholesterol levels, and diabetes. Scientific data supporting the health value of exercise is compelling enough that a wide variety of health agencies including the American College of Sports Medicine, the American Heart Association, the Centers for Disease Control and Prevention, the National Institutes of Health, and the Surgeon General of the United States have issued pronouncements regarding the health benefits of exercise. Health clubs are specialized facilities designed to allow participants to exercise in a stimulating environment and have access to a variety of specialized equipment and programs. These facilities are important to persons who want to achieve their exercise goals. The role of such facilities dates back at least to the 19th century.
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Exercise while Traveling

Regular exercise is an important component of a healthy lifestyle. The American College of Sports Medicine, the American Heart Association, and other prominent organizations have issued recommendations to encourage individuals to establish and maintain participation in an exercise program. A potential impediment to an exercise program is the conflict that can be created by a business trip, which is a common event for many Americans. While it is not advisable for an individual to begin an exercise program while on a business trip, it is recommended that exercise habits be maintained while traveling.
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Exercise-Induced Leg Pain

Anatomically speaking, the “leg” is the region between the knee and the ankle. Repetitive weight-bearing exercise commonly causes painful injuries in this region. The sources of leg pain are varied, but the cause is often the same. The pursuit of athletic excellence has now reached such phenomenal extremes the human body is often subjected to degrees of physical work it is not designed to tolerate. While most body tissues have the capacity to adapt and strengthen in response to increased loading, overuse injuries result when the increased loading occurs too quickly for the adaptation to take place.
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Explosive Exercise

Explosive exercise can be defined as movements in which the rate of force development (RFD) is maximum or near maximum for a given type of muscle action (e.g. isometric, concentric, eccentric). The peak RFD has a strong association with the ability to accelerate a mass. Explosive exercise may be performed isometrically or dynamically; however, dynamic movements can produce higher RFDs than isometric exercise. As the resistance used for dynamic movements decreases, the RFD increases resulting in an inverse relationship between peak force production and RFD. Thus, a continuum of explosive exercise can be conceptualized ranging from isometric movements and high force slow movements (very heavy weights) to very fast movements performed with relatively light weights. Depending upon the resistance used, a high RFD, high acceleration and power output can be achieved within the same movement. Explosive exercises in which all three parameters (RFD, acceleration and power) are at maximum or near maximum can be termed "speed strength" exercises and may be plyometric or ballistic in nature.
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Football Helmet Removal

Each year, thousands of head and neck injuries occur to football players of all skill levels. Such sports injuries are among the most dreaded because they can cause paralysis or death. Football players suffering neck injuries must be properly managed to prevent further injury. Presently, the protocol for football helmet removal differs among sports medical and emergency medical personnel. The American College of Sports Medicine (ACSM) strongly advises against removing the helmet from an unconscious athlete or from an athlete who has sustained a neck injury. Medical personnel should suspect that any unconscious athlete has an accompanying spinal injury until proven otherwise, because head and neck trauma frequently occur together. Proper immobilization of the spine and safe transportation to the hospital can be accomplished without removal of the helmet because, unlike motorcycle helmets, football helmets fit snugly and prevent head movement within the helmet.
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Growth in Young Wrestlers

Wrestling is a popular and growing interscholastic sport. A key element to this popularity is that wrestling offers an opportunity for large numbers of young men, and increasingly more young women, to compete in a vigorous, aggressive physical activity wherein competition is, in theory, equalized by the formation of numerous weight classes. Thus, young people have an opportunity to participate in an athletic activity not limited by the size of the individual. Historically however, wrestling has been jeopardized because of excessive weight loss practices by many wrestlers. Wrestlers traditionally lose weight for two basic reasons: (1) to gain an alleged advantage over a smaller opponent and/or (2) to make the team by changing to another weight class so as not to compete with a superior team member in a higher weight class. Parents, athletic officials and health professionals have long been concerned about the methods used for rapid weight loss including severe dehydration, caloric restriction, diuretics, diet pills, laxatives, rubber exercise suits, vomiting, and other methods. The American College of Sports Medicine (ACSM) and the American Medical Association have expressed great concern regarding the effects of repeated bouts of excessive weight loss or weight cycling, particularly in athletes who are still growing.
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Heat and Hydration in Young Tennis Players

Most junior tennis tournaments—of the 5,000 United States Tennis Association (USTA) sanctioned junior tournaments held each year—are played outdoors in warm to hot climates. The level of play and depth of competition continue to improve, but the toughest opponent these young athletes often face (even at the National Championships level) is the heat. Heat stress can readily reduce on-court performance; it can also threaten a player’s health and safety. Even players who are fit and take the necessary precautions can suffer from heat stress, making performance very difficult. One of the best ways a tennis player can better tolerate competing in the heat is to maintain adequate hydration. While most tennis players acknowledge the importance of drinking plenty of fluids and the benefits of staying well hydrated, many well-trained and “informed” players – in the juniors and up through the professional ranks – continue to have hydration-related problems. Notably, the risks associated with competition in the heat seem to be greater with young players, in part because of thermoregulatory challenges related to being a child or adolescent. Junior players also often play more than one match a day during tournaments. This presents greater recovery challenges and more readily prompts symptoms related to accumulated fluid, energy, and electrolyte deficits. Problems range from just being a little “off” to heat cramps or, more severely, heat exhaustion. Regular and copious water intake is often not enough; to play well and safely in the heat, a young tennis player must manage a number of factors related to helping the body endure the heat stress.
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High-Velocity Training

Interest in the science of strength training and its associated benefits is a growing phenomenon within the fitness movement. The fact that approximately eight weeks of heavy resistance training can produce significant gains in strength is well established. The consensus position supported by hundreds of experimental studies is that gains in strength are the primary result of increased muscle size, referred to as hypertrophy. What is less well known is the phenomenon that results in the manifestation of increased strength after only a few strength-training sessions. Speculation is that these short-term effects are the results of changes in neural factors. Studies have shown that short-term resistance training can increase strength production in the absence of hypertrophy. While neural factors are not well defined, these early strength gains are largely attributed to an increase in the maximal muscle activation level.
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Menstrual Cycle Dysfunction

During the past few decades, increasing numbers of women of all ages have been participating in sports, at both recreational and competitive levels. Most girls and women derive significant health benefits from regular physical activity. They can achieve the same training effects as do men, such as decreased blood pressure, lowered heart rate, and improved aerobic capacity, as well as decreased percent body fat. These changes help protect against atherosclerosis and heart disease. In addition, weight-bearing exercise promotes strong and healthy bones. Earlier myths regarding detrimental effects of excessive exercise on the female reproductive system have been largely dispelled. However, athletes, parents, coaches and physicians should be aware that exercising women could potentially be subject to menstrual cycle dysfunction.
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Lifestyle and Pediatric Metabolic Syndrome

Due to a culture in many households that encourages obesity, a relatively new health problem that exposes individuals to a greater risk of morbidity and mortality has been identified in children. The metabolic syndrome has been recognized in adults for the last 20 years, but only recently has been identified in children, as indicated in a 2005 ACSM news release. The syndrome is not a disease, but a group of risk factors for developing chronic diseases such as diabetes, blood vessel and heart diseases. It was originally called “insulin resistance syndrome,” but is composed of a number of metabolic irregularities and was later named the metabolic syndrome. Insulin resistance is a significant contributor to the metabolic syndrome. The pre-culture for type 2 diabetes has only recently been observed in children and the current obesity epidemic, so it is not surprising that “pediatric metabolic syndrome” is a relatively new term.
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Overtraining with Resistance Exercise

One of the fastest growing and most popular types of exercise in recent years is resistance exercise, whether used for the purpose of general fitness, rehabilitation, or athletic performance. Resistance exercise comes in many different forms, each of which can produce distinctly different responses (e.g. increased size, strength, power, contraction velocity, muscular endurance, etc.). Each individual training session can be described by the five acute training variables: choice of exercise, order of exercise, exercise volume (sets x repetitions), load or intensity (percent repetition maximum), and rest (between sets). Each of these variables present numerous possible combinations resulting in literally thousands of possible single-session protocols. Over a longer training period or cycle, the training variables can be altered to provide the individual with the necessary variability for long-term improvement. Such variety in the long-term program is called periodization, and helps to ensure that the body is continually being presented with a stress that permits both progress and adequate recovery. Often associated with training programs for advanced athletes, such training variety is also critical for the individual who is embarking on a lifetime exercise program for general fitness. This variation of the resistance exercise prescription also avoids the monotony that can occur when the identical exercise protocol is performed each session with little or no variation.
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Posterior Cruciate Ligament (PCL) Injuries

Knee injuries are unfortunately common in sport. Much attention has been paid to injuries to the anterior cruciate ligament (ACL) secondary to the disability it poses for an athlete, but little emphasis has been placed on its neighbor, the posterior cruciate ligament (PCL). The PCL is described as being injured in 3-20 percent of all sport knee injuries. Many more athletes may have suffered damage to this ligament and may not have had it identified. These injuries occur most often during game play; competitive athletic teams can expect one PCL injury per season, although no one factor has been identified as a dominant cause of PCL injury. The anatomy of the PCL, which is stronger than the ACL, contributes to the stability of the knee in both flexion and extension because it has two ligamentous bundles that form the PCL, the anterolateral bundle that tightens in flexion and the posterolateral bundle, which tightens in extension. The most common way the PCL is injured in sport is when the individual falls on a bent knee with the toes pointed. Other ways the PCL is torn is by hyperextension, a blow to the tibia with the knee flexed, or a combination of rotation and lateral force directed at the side of the knee, forcing it into hyperextension.
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Perceived Exertion

Around the world in health clubs on the walls beside treadmills, stationary bikes and step machines, one often sees a scale going from 6-20. This is called an RPE Scale, which stands for “Rate of Perceived Exertion.” It is a psychophysiological scale, meaning it calls on the mind and body to rate one’s perception of effort. Understanding the meaning and use of this chart will benefit the average fitness enthusiast. The RPE scale measures feelings of effort, strain, discomfort, and/or fatigue experienced during both aerobic and resistance training. One’s perception of physical exertion is a subjective assessment that incorporates information from the internal and external environment of the body. The greater the frequency of these signals, the more intense are the perceptions of physical exertion. In addition, response from muscles and joints helps to scale and calibrate central motor outflow commands. The resulting integration of feedforward-feedback pathways provides fine-tuning of the exertional responses.
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Physiology of Aging

Aging defies easy definition, at least in biological terms. Aging is not just the passage of time, but rather an accumulation of biological events that occur over a span of time. If we define aging as the loss of one's ability to adapt to a changing environment, then biological or functional age becomes a measure of one's success for adaptation. At the turn of the twentieth century, approximately four percent of the United States population was over age 65; today, it has climbed to 13%. Life expectancy at birth in the U.S. has increased to about 76 years today, and is expected to reach 83 years by 2050. The absolute number of older persons, currently about 36 million, has increased 11-fold, compared to only triple in the entire U.S. population. As individuals age, especially past 85 years, there is a growing need for assistance with everyday activities; half that group needs some assistance. Thus, as individuals live longer, we must determine the extent and mechanisms by which exercise and physical activity can improve health, functional capacity, quality of life, and functional independence.
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Plyometric Training

Children and adolescents need to participate regularly in physical activities that enhance and maintain cardiovascular and musculoskeletal health. While boys and girls have traditionally been encouraged to participate in aerobic training and strength building activities, a growing number of children and adolescents are experiencing the benefits of plyometric training. Plyometrics refer to exercises that link strength with speed of movement to produce power and were first known simply as “jump training.”l exercise programs targeted at improving the musculoskeletal and/or cardiorespiratory systems.
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Pre-Event Meals

It is well established that exercise performance can be affected by diet and, in order to maintain optimal training, the body must be properly refueled with appropriate nutrients. The pre-event meal is an integral part of the complete training plan. Of course, a single pre-event meal will not compensate for a poor training diet. For this reason, the active person should routinely follow basic nutrition guidelines. It is essential that the diet contain enough calories to cover the active person’s daily energy expenditure. It is also advised that the diet be composed of a wide variety of foods to ensure adequate intake of vitamins and minerals. The training diet should be high in carbohydrate without compromising necessary protein and fat.
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Pre-Season Conditioning for Young Athletes

Over the past few decades the number of recreational and competitive sports programs for children and adolescents has increased dramatically. There are more opportunities for girls to participate in sports, and in some communities children as young as age six can join organized teams and leagues. With qualified coaching and age-appropriate instruction, sports programs can provide young athletes with an opportunity to enhance their physical fitness, improve self-esteem, acquire leadership skills and have fun. However, there is the potential for illness or injury if boys and girls are unfit and ill-prepared to handle the demands of their chosen sport.
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Resistance Training and the Older Adult

The health benefits of appropriately prescribed long-term (more than 12 weeks) resistance training in older adults--ages 65 and older--are well known. They include improvements in muscle strength and endurance; other possible health benefits include increase in muscle mass, which translates into improvements in functional capacity. In addition, increased weight bearing with resistance training is considered beneficial in improving bone density and combating the effects of osteoporosis. Achieving appropriate levels of function is very important for older adults so they are able to carry out most of the daily living skills necessary to lead independent lives. Due to the fact that muscle wasting (sarcopenia) and weakness, exacerbated by physical inactivity, is prevalent in the aging population, more emphasis has been placed on developing resistance-training programs for older adults. When developing resistance-training programs for this group, important components to consider are the various training-related variables: frequency, duration, exercises, sets, intensity, repetitions, and progression.
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Resistance Training and Injury Prevention

The benefits of resistance training in both competitive and recreational athletes have been well documented over the past 20 years. Improvements in muscle strength and power, increase in muscle size, and improvement in sports performance are common benefits resulting from resistance training programs. In addition, resistance training has also been suggested to reduce the risk for musculoskeletal injuries, or perhaps reduce the severity of such injury. Although studies reporting the direct effect of resistance training on injury rate reduction are limited, the physiological adaptations seen consequent to resistance training on bone, connective tissue and muscle does imply enhanced protection against injury for individuals who participate in such a training program.
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Physical Training for Improved Occupational Performance

As athletes strive to improve their performance through effective training techniques, so too can workers benefit from optimally planned exercise training programs designed to boost occupational physical performance. Similar to athletics--where skill and fitness demands vary between that of the recreational and the professional athlete--occupational physical demands can vary among employment settings. Physically demanding occupations, such as those found in the armed services, emergency rescue professions, and construction and warehouse industries, require a high degree of physical fitness. Job performance in these occupations can be augmented by participation in formal exercise programs targeted at improving the musculoskeletal and/or cardiorespiratory systems.
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Safety of the Squat Exercise

The squat is typically a barbell exercise where the individual starts in a standing position with the barbell on the back, and bends the knees to squat down until the thighs are parallel with the floor. It has been the subject of some controversy in exercise prescription, primarily related to the belief that it causes knee or low back pain or injury. However, when examining the safety of the squat, it is appropriate to review the history, science, and practical application of this activity.
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Sickle Cell Trait

Sickle cell trait is not in itself a disease. It is a descriptive term for a hereditary condition in which an individual has one normal gene for hemoglobin (A) and one abnormal gene for hemoglobin (S), giving the genetic type (AS). Sickle cell trait condition (AS) is different from sickle cell anemia disease (SS), in which two abnormal genes are present. Approximately eight to ten percent of the U.S. black population has sickle cell trait, while less than one percent exhibit sickle cell anemia. Sickle cell trait is found in non-black athletes as well as black athletes, although, in a much lower frequency. It is present in athletes at all levels of competition, including professional and Olympic. Sickle cell trait is not a barrier to exercise or participation in sport. In general, sickle cell trait is a benign condition that does not affect the longevity of the individual. Persons who carry the sickle cell trait alone do not have the associated anemia. However, sickle cell trait has been definitively linked to splenic infarction with cases apparently occurring more frequently in non-blacks. This situation typically occurs at high altitudes (usually greater than 5,000 feet), although a case has been described near sea-level. Symptoms of a splenic infarction include sudden acute pain in the lower ribs, weakness and nausea. It appears that strenuous physical exertion after a recent arrival at altitude is a common theme. Although there are more than two million people in the U.S. with sickle cell-trait, only a few cases of splenic infarction are reported each year.
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Skiing Injuries

Downhill skiing continues to increase in popularity. The skiing industry has made the sport accessible to more people. Faster ski lifts and expansion of trails at ski areas, as well as improved snow making capabilities, have increased the numbers of skiers on the slopes. Dramatic changes have occurred in the equipment as well. Ski boots have evolved from soft leather cut boots to mid-calf plastic boots that rigidly support from the lower leg and ankle. Advancements in binding design continue to reduce the number of lower extremity injuries. The American College of Sports Medicine (ACSM) endorses the use of these more sophisticated multi-directional release bindings. Falls are an obvious cause of injuries, accounting for approximately 75 to 85 percent of skiing injuries. Collisions with objects including other skiers, account for between 11 and 20 percent, while incidents involving ski lifts contribute between 2 and 9 percent. Studies demonstrate that the majority of injuries are sprains, followed by fractures, lacerations and dislocations.
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Strength, Power and the Baby Boomer

As we begin the new millennium, we face many challenges relating to the health and fitness of a rapidly aging society. Perhaps the greatest challenge is helping the “baby boomers” age gracefully, adding life to their years. The baby boomers are the largest generation in U.S. history, representing one-third of our present population. Around 2011 the first of the baby boom generation will turn 65. By 2030, boomers will enter their seventies and eighties, doubling the number of elderly adults, with one out of every five adults over 65 years of age. Further, the “oldest-old” (those over 85 years) are estimated to grow from five million presently, to over 20 million. Baby boomers do not need to age quietly. Boomers have economic and political power as well as the power to reject the stereotype of ageism, frailty and inactivity. They can continue to pursue vigorous, active lives well into old age. Life extension is an admirable goal, but not at the expense of good health and quality of life. Crucial to the boomers’ enjoyment of their golden years are maintaining and improving muscular strength and power through resistance training. Whether performing daily chores or playing a round of golf, muscular strength and power significantly impact the boomer’s ability to function with vigor, enjoying life to the fullest.
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Strength Training for Bone, Muscle and Hormones

One of the hallmark features of aging is loss: loss of bone strength, muscle mass and strength and hormone production. Although the debate continues as to the cause of this loss, one thing is certain: the inclusion of regular strength training sessions will play an important role delaying and reducing age- or inactivity-associated loss experience.
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Stress Fractures

Stress fractures comprise between 0.7 and 15.6 percent of all athletic injuries. Athletes particularly at risk of stress fracture are runners and jumpers, gymnasts and dancers. Stress fracture incidence among U.S. military recruits is also high, ranging from approximately one to 20 percent, with higher rates reported for women than for men. In general, the bones most commonly injured are the metatarsals, fibula and tibia.
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Tennis Elbow

Since the creation of modern tennis in 1873, participants have suffered from pain in and around the elbow of their racket arm. The first documented medical reference to the condition of tennis elbow or “lawn tennis arm” was published in 1883 with recommendations including treating the problem with rest and compression bandages fixed just distal to the painful area of the forearm. The situation has not changed greatly over the past 125 years. Half of all tennis players will suffer from tennis elbow at some time during their playing careers, and players still employ compression wraps to alleviate pain. However, the average person who develops tennis elbow is not a tennis player. Only five per cent of those who suffer from tennis elbow are injured due to their participation in the sport of tennis. Most often the injury results from excessive use of such tools as a hammer or screwdriver.
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Vitamin and Mineral Supplements and Exercise

People who engage in physically active lifestyles are frequently targets of advertisements proclaiming the need for vitamin and mineral supplements. These advertisements presume that athletes, ranging from international competitors to weekend participants in recreational activities, are at risk of developing nutritional deficiencies and subsequent impairments in performance and health. Surveys of athletes indicate the success of these advertisements; the prevalence of use of vitamin and mineral supplements is widespread. Estimates indicate that more than 50% of elite, female endurance athletes and about 40% of non-elite male athletes regularly consume vitamin and mineral supplements.
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Weight Loss in Wrestlers

For more than a half century, rapid weight loss in wrestling has remained a concern among educators, health professionals, exercise scientists and parents. Since ACSM first published the Position Stand “Weight Loss in Wrestlers” in 1976, numerous research articles have been published on this topic. On a weekly basis, rapid weight loss in high school and collegiate wrestlers has been shown to average 4-5 lbs. and may exceed 6-7 lbs. among 20% of the wrestlers. One-third of high school and collegiate wrestlers have been reported repeating this practice more than 10 times in a season. These practices have been documented over the past 25 years, and during that time, there appears to be little change in their prevalence.
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Youth Strength Training

Fitness training has traditionally emphasized aerobic exercise such as running and cycling. More recently, the importance of strength training for both younger and older populations has received increased attention, and a growing number of children and adolescents are experiencing the benefits of strength training. Contrary to the traditional belief that strength training is dangerous for children or that it could lead to bone plate disturbances, the American College of Sports Medicine (ACSM) contends that strength training can be a safe and effective activity for this age group, provided that the programs properly designed and competently supervised. It must be emphasized, however, that strength training is a specialized form of physical conditioning distinct from the competitive sports of weightlifting and powerlifting, in which individuals attempt to lift maximal amounts of weight in competition. Strength training refers to a systematic program of exercises designed to increase an individual's ability to exert or resist force.
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Women's Heart Health and an Active Lifestyle

Coronary heart disease (CHD) is the leading cause of death in women and men, but more women than men die each year of CHD. The overall risk of heart attack in women is close to that of men a decade younger, but with increasing age, the risk of heart attack becomes similar in men and women. Of great concern is the fact that death rate due to CHD in women ages 35-74 is 74 percent higher in black than in white women. Despite these statistics, clinicians and the public often cite breast cancer and osteoporosis as the greatest health risks for women over 50 years. These misconceptions regarding women’s heart health are startling, considering that the lifetime risk of death from CHD among postmenopausal women is approximately 31 percent compared to 2.8 percent for hip fracture and breast cancer alike.
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Exercise for Persons with Cardiovascular Disease

Cardiovascular disease is the leading cause of mortality in the U.S. It accounts for almost 50% of all deaths each year and affects nearly 14 million Americans. This number includes those with angina pectoris (chest pain) as well as persons with impairment of the heart’s ability to pump effectively (congestive heart failure), resulting in inadequate blood flow to the tissues. Nearly 1.5 million Americans have heart attacks each year, and about a third of them die. What’s more, heart attacks are equal opportunity killers: About half of the nearly 500,000 annual heart attack deaths are among women. And, every year more than 700,000 patients with heart disease undergo either bypass surgery or balloon angioplasty. Treatment for persons with heart disease is multifaceted and includes smoking cessation, cholesterol reduction, blood pressure control and exercise training.
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