Council Publications

Physical Activity & Sport in the Lives of Girls

Physical & Mental Health Dimensions fom an Interdisciplinary Approach

Under the Direction of

The Center for Research on Girls & Women in Sport University of Minnesota

Supported By

The Center for Mental Health Services / Substance Abuse and Mental Health Services Administration, U.S. Department of Health and Human Services
Spring 1997

PROJECT DIRECTORS

Mary Jo Kane, Ph.D.
Associate Professor and Director, Center for Research on Girls & Women in Sport
University of Minnesota, Minneapolis, Minnesota

Deborah Slaner Larkin
Council Member, President’s Council on Physical Fitness and Sports Washington, D.C.
Steward, Women’s Sports Foundation, East Meadow, New York

RESEARCH ADVISORY PANEL

Elizabeth Arendt, M.D.
Associate Professor, Department of Orthopaedic Surgery, University of Minnesota Minneapolis, Minnesota

Linda K. Bunker, Ph.D.
Associate Dean of Academics and Students Affairs, University of Virginia
Charlottesville, Virginia

Juliann DeStefano, R.N., M.P.H.
Special Assistant, Office of the Director, Center for Mental Health Services,
Substance Abuse and Mental Health Services Administration, U.S. Department of
Health and Human Services
Rockville, Maryland

Mary Ann Hill, M.P.P.
Director of Communications, President’s Council on Physical Fitness and Sports
Washington, D.C.

Gwendolyn Puryear Keito, Ph.D.
Director, Women’s Programs Office, American Psychological Association
Washington, D.C.

Judy Mahle Lutter
President, Melpomene Institute
St. Paul, Minnesota

Sandra Perlmutter
Executive Director, President’s Council on Physical Fitness and Sports
Washington, D.C.

Don Sabo, Ph.D.
Professor of Sociology, D’Youville College
Buffalo, New York

Christine G. Spain, M.A.
Director of Research, Planning, and Special Projects
President’s Council on Physical Fitness and Sports, Washington, D.C.

CONTENT EDITOR: Linda K. Bunker, Ph.D.
COPY EDITOR: Katherine Pradt
PUBLICATION DESIGN: Nance Longley
PRODUCTION: Jonathan Sweet, Arlene West

The year 1996 marked a breakthrough in our understanding of the benefits of physical activity and health for all Americans. With the publication of the first Surgeon General’s Report on Physical Activity and Health, we have clearly documented the fact that men and women of all ages can improve the quality of their lives through a lifelong practice of regular moderate physical activity. And the research indicates that physical activity need not be strenuous to achieve real health benefits. A regular, preferably daily routine of at least 30-45 minutes of brisk walking, bicycling, or even dancing will reduce the risks of developing coronary heart disease, hypertension, colon cancer, and diabetes. Moreover, regular physical activity can reduce symptoms of depression and anxiety; help control weight; and help build and maintain healthy bones, muscles and joints.

Childhood and adolescence are critical times to lay the foundation for lifelong physical activity, but, unfortunately, too many young people, especially girls, are not active enough. As children grow into adolescence, their participation in physical activity declines dramatically. As the Surgeon General’s report tells us, almost half our young people aged 12 to 21 are not vigorously active on a regular basis and 14 percent are completely inactive. And young females are twice as likely to be inactive as young males.

These are dangerous trends, and we need to change them. Fortunately, this landmark report on Physical Activity & Sport in the Lives of Girls from the President’s Council on Physical Fitness and Sports tells us some of the steps we can take to enable girls to reach their full potential. It tells us that we need to provide more quality school-based physical education for girls. It tells us that we need to encourage girls to get involved in sport and physical activity at an early age. It tells us that we need to challenge stereotypes that impede girls’ participation in sports. And it tells us that we have made progress in some areas. For example, the Title IX legislation enacted in 1972 has opened the doors for millions of girls to participate in school sports.

Americans took enormous pride in the accomplishments of the 1996 Olympic gold medal female athletes in soccer, softball, swimming, track and field, gymnastics, basketball, and other sports. We need to build on that spirit and develop a national commitment to ensure that every girl receives the encouragement, training, and support she needs to develop and maintain an active lifestyle. Increasing physical activity among girls is a formidable public health challenge, but the potential rewards are great: a more vigorous nation, better health and greater leadership opportunities for girls, prevention of premature death and unnecessary illness, and a higher quality of life for our citizens. I strongly encourage all Americans to join us in this effort.

In the summer of 1996, our nation cheered the performance and achievements of the U.S. women Olympians and Paralympians. The images of strong, active women were inspiring, a long way from the days when females were relegated to “lady-like” sports and young girls were left on the sidelines as their brothers played.

Following on the heels of the Surgeon General’s Report on Physical Activity and Health, this landmark review makes clear that participation in physical activity and sport can help girls weather the storms of adolescence and lay the foundation for a healthier adult life. The report looks at “the complete girl” through an interdisciplinary approach to investigate the impact of physical activity and sport participation.

The conclusions are striking: regular physical activity can reduce girls’ risk of many of the chronic diseases of adulthood; female athletes do better academically and have lower school drop-out rates than their nonathletic counterparts; and, regular physical activity can enhance girls’ mental health, reducing symptoms of stress and depression and improving self-esteem.

But further vigilance and research are needed to ensure that all girls and boys can experience these same benefits. While Title IX has a tremendous impact on expanding physical activity opportunities for females, its compliance and enforcement have often wavered. Parents, teachers, and coaches should be encouraged to challenge stereotypes about girls’ participation in physical activity and sport. There is a lack of information and research about how race, ethnicity, and socioeconomic status might affect girls’ sport and fitness involvement.

I greatly appreciate the support of the Members of the President’s Council for this endeavor, which stemmed from the Council’s Task Force on Girls and Minorities. Their enthusiasm and unflinching support for expanding the reach of the PCPFS into important areas such as this have been critical to the successful completion of this important project.

Council Member Deborah Slaner Larkin deserves special recognition for her vision and commitment to this report and for her many years of leadership in promoting opportunities in physical activity and sports for girls and women.

I would like to thank the Center for Research on Girls & Women in Sport, under the able leadership of Dr. Mary Jo Kane, and the Center for Mental Health Services, our partners in this endeavor.

It is my hope that this report will serve as a catalyst for parents, coaches, educators, researchers, and community leaders to encourage and create opportunities for girls and young women to become— and remain—more physically active throughout their lives.

Sandra Perlmutter
Executive Director

On behalf of the President’s Council on Physical Fitness and Sports, we are honored to present this research report. All of us who have been involved with the project have a great respect for the power that sport and physical activity can wield. Such involvement has helped shape our lives. In fact, it is a major reason why many of us have chosen this area as our life’s work.

Physical Activity and Sport in the Lives of Girls: Physical and Mental Health Dimensions from an Interdisciplinary Approach was created to highlight the multiplicity of ways in which physical activity and sport have become an integral part of girls’ lives. It examines the benefits girls derive from participation in physical activity and sport; the barriers that prevent them from reaching their full potential; and the kinds of environments in which girls learn how to develop and foster the best parts of themselves both on and off the playing fields. The report was also created to develop future research paths and policy recommendations as a guide for planning and programming.

This is a groundbreaking report because it marks the first time an interdisciplinary approach has been used in a government document that examines the impact of sport and physical activity in the lives of girls. We have chosen authors who are experts in the physiological, sociological, psychological and mental health fields to each write a section discussing significant issues in their respective academic areas. The interdisciplinary approach is particularly important because it enables us to talk about the “complete girl”—her social, physical, emotional and cultural environment—rather than just one aspect of a girl’s experience. It should be noted that, on occasion within the report, the authors present differing points of view with respect to certain research findings. For example, scientific studies in the mental health field may suggest a particular relationship between self-esteem and physical activity that has not been identified in the area of sport sociology. This should not be interpreted as problematic or contradictory; instead, it can be viewed as an opportunity for further discussion and for reinforcement of the need for future interdisciplinary research. Finally, one strength of this report is a reference list that includes numerous citations from a variety of academic disciplines. Such a list can be an invaluable resource for academics, educators and practitioners.

Related to the issue of interdisciplinarity, you will find when reading the report that different authors use different terminology when talking about girls. As a general rule, however, the word “girl” is used when authors are referring to girls 18 and under. Other terminology is used to further delineate age. For example, “adolescent female” typically refers to girls between the ages of 13-18, while “young girl” generally signifies 11 and under.

While the amount of research covered in this report is thorough and in-depth, because of space limitations, we could not include every aspect of what is known about the many ways in which sport and physical activity influence girls. We also addressed many issues related to diversity such as cultural or racial heritage and different physical abilities. However, what is clear from the authors’ findings is that we have a great deal more to learn about the particular ways in which involvement in sport and physical activity affects minority groups of girls. We urge others to use this document as a way to pursue future areas of research; many potential directions are outlined in detail in the authors’ research sections.

It is important that the information presented in this document reaches a variety of audiences from parents, teachers and coaches to administrators and policy makers in educational institutions and government agencies. Everyone involved in the lives of our children needs to know what factors contribute to girls’ development. Our hope is that those most able to effect change will use this information as a vehicle for pursuing future areas of research and developing and implementing programs that will make a difference in one of this country’s most important assets—girls.

Finally, this report is dedicated to all of the parents, physical education teachers, coaches and athletic administrators who recognize the importance of sport and physical activity for all girls. These hard-working individuals spend their days on the ball fields and playgrounds teaching skills and developing a young girl’s character. They are on the phone at night organizing the next game, event or season. Their weekends are often spent at meetings and conferences. They fight for Title IX compliance, coverage of a game or a walkathon in the local paper, new uniforms, adequate facilities and safe fields.

Without their commitment and dedication to bettering the lives of girls throughout this country, this report would not have been possible. We are all in their debt!

THE PRESIDENT’S COUNCIL ON PHYSICAL FITNESS AND SPORTS (PCPFS) serves as a catalyst to promote, encourage and motivate the development of physical activity, fitness and sports participation for all Americans of all ages. Established by Executive Order in 1956, the PCPFS is made up of twenty members appointed by the President. Assisted by elements of the United States Office of Public Health and Science, the PCPFS provides guidance to the President and the Secretary of Health and Human Services on how to get more Americans physically active.

THE CENTER FOR RESEARCH ON GIRLS & WOMEN IN SPORT (CRGWS) is dedicated to examining how sport and physical activity impact the lives of young girls and women. The first of its kind in the country, the CRGWS is an interdisciplinary research center leading a pioneering effort on significant social and educational issues. The CRGWS is equally committed to teaching and mentoring students and to community outreach and public service.

THE CENTER FOR MENTAL HEALTH SERVICES, Substance Abuse and Mental Health Services Administration, U.S. Department of Health and Human Services, provides national leadership for improving the quality and availability of treatment and prevention services for mental illness, particularly with respect to adults with serious mental illness and children with serious emotional disturbances.

This comprehensive report is funded by the Center for Mental Health Services, Substance Abuse and Mental Health Services Administration, U.S. Department of Health and Human Services. The Project Directors are grateful to the Center for Mental Health Services, Substance Abuse and Mental Health Services Administration, U.S. Department of Health and Human Services, for their support in making this study possible. It will enable us to provide information to educators and decision makers who are in a position to make a difference in the lives of girls across the country.

Appreciation is extended to the following individuals, all of whom have made a significant contribution to the preparation of this report: Leslie Fisher, Ph.D. (University of Virginia); Darlene Kluka (Oklahoma State University); Judy Mahle Lutter, President (Melpomene Institute, St. Paul MN); Gloria Solomon, Ph.D., (Texas Christian University); Diane Wakat, President (Intelligent Nutrition Systems, Charlottesville VA); Art Weltman, Ph.D. (University of Virginia); Jennifer Fiedelholtz, M.P.P., Acting Associate Administrator (Office of Women’s Services—Substance Abuse and Mental Health Services Administration); Nance Longley, Publications Designer/Production Assistant (College of Education and Human Development, University of Minnesota); Debra Haessly, Executive Assistant (School of Kinesiology and Leisure Studies, University of Minnesota); Shelly Shaffer, Ph.D. (Center for Research on Girls & Women in Sport, University of Minnesota); LeeAnn Kriegh, M.A. (Center for Research on Girls & Women in Sport, University of Minnesota); Jonathan Sweet, Executive Assistant (Center for Research on Girls & Women in Sport, University of Minnesota); Janet Spector, Associate Professor (Departments of Anthropology and Women’s Studies, University of Minnesota); Bernard S. Arons, M.D., Director (Center for Mental Health Services, Substance Abuse and Mental Health Services Administration, U.S. Department of Health and Human Services); Layne Owens, Special Assistant to the Executive Director (President’s Council on Physical Fitness and Sports).

THE PRESIDENT’S COUNCIL ON PHYSICAL FITNESS AND SPORTS (PCPFS) serves as a catalyst to promote, encourage and motivate the development of physical activity, fitness and sport participation for all Americans. This report expresses the PCPFS’s mission to inform the general public of the importance of developing and maintaining physical activity and fitness in our daily lives, and to heighten awareness of the links that exist between regular physical activity and good health. In the past, involvement in sport and physical activity has been primarily associated with males. Over the past two decades, however, girls’ and women’s involvement in such activity has increased dramatically. This is in large part due to the impact of Title IX, federal legislation passed in 1972 designed to prohibit sex discrimination in educational settings. For example, prior to Title IX, 300,000 young women participated in interscholastic athletics nationwide; today, that figure has leaped to approximately 2.25 million participants. In the wake of this participation explosion, scholars and educators have begun to explore its impact on girls and women.

Physical Activity and Sport in the Lives of Girls: Physical and Mental Health Dimensions from an Interdisciplinary Approach was created in order to highlight relevant research and draw on expert opinion regarding girls’ involvement in physical activity and sport. This is the first report that brings together research findings—and practical suggestions for implementing these findings—from three interdisciplinary bodies of knowledge: physiological, psychological and sociological. An additional section explores the relationships among physical activity, sport and the mental health of girls. The primary goal was to identify and discuss the beneficial ways that physical activity and sport influence girls’ physical health, psychological well-being and overall social and educational development. An additional goal was to identify the problematic aspects of girls’ involvement. These include, but are not limited to, eating disorders, gender stereotyping and institutional barriers such as lack of opportunity and access to various resources. Although this report examines some of the most current and cutting-edge issues, because of space limitations, the authors do not claim to include all relevant research and concerns surrounding girls’ involvement with sport and physical activity.

The report focuses on girls and not boys (other than for comparison where appropriate) for several reasons. First, with respect to sport and physical activity, girls have been neglected by researchers in the biomedical sciences, education, physical education and the social sciences. Second, though girls and boys share common experiences, girls also exhibit unique physiological, emotional and social outcomes that merit special investigation. Next, scholars need to keep pace with the aforementioned explosion and diversification of girls’ involvement with sport and physical activity in the wake of Title IX. And finally, researchers increasingly recognize that the social world of physical activity and sport is not a one-dimensional universe, but a highly complex set of institutions populated by two genders with diverse racial and ethnic backgrounds, cultural values, physical abilities and sexual orientations.

Public apathy about physical education, and the glitzy distractions of commercialized sports in mass media, sometimes hide the basic fact that physical activity is a public health resource for millions of American girls as well as their families and communities. In order to advance knowledge regarding the real and potential contributions of physical activity and sport in the lives of millions of girls, several areas for future research are highlighted by the authors at the end of each section. Finally, a set of policy recommendations is also included in order to encourage responsible action on the part of parents, coaches, educators, sport leaders and elected officials. With such a “teamwork” approach, we can make a difference in the lives of girls.

KEY RESEARCH FINDINGS

Some of the most important research findings documented and highlighted in this report suggest that:

• More girls are participating in a wider array of physical activities and sports than ever before in American history. (Introduction)

• Regular physical activity in adolescence can reduce girls’ risk for obesity and hyperlipidemia (i.e., high levels of fat in the blood)which, in turn, have been known to be associated with lower adult onset of coronary heart disease and certain cancers. Regular physical activity can also help girls build greater peak bone mass, thereby reducing adult risk for osteoporosis. (Research Report, Section I)

• Exercise and sport participation can be used as a therapeutic and preventative intervention for enhancing the physical and mental health of adolescent females. (Research Report, Section IV)

• Exercise and sport participation can enhance mental health by offering adolescent girls positive feelings about body image, improved self-esteem, tangible experiences of competency and success and increased self-confidence. (Research Report, Sections II and IV)

• Research suggests that physical activity is an effective tool for reducing the symptoms of stress and depression among girls. (Research Report, Sections II and IV)

• Sports are an educational asset in girls’ lives. Research findings show that many high-school female athletes report higher grades and standardized test scores and lower dropout rates, and are more likely to go on to college than their nonathletic counterparts. (Research Report, Section III)

• Recognition of physical activity and sport as an effective and money-saving public health asset is growing among researchers and policy makers. (Introduction; Research Report, Sections I, II and IV)

• Poverty substantially limits many girls’ access to physical activity and sport, especially girls of color who are overrepresented in lower socioeconomic groups. (Introduction; Research Report, Section III)

• Excessive exercise and certain forms of athletic participation have been found to be associated with a higher prevalence of eating disorders. (Research Report, Sections I, II, III and IV)

• The potential for some girls to derive positive experiences from physical activity and sport is marred by lack of opportunity, gender stereotypes and homophobia. (Research Report, Sections III and IV)

CONCLUSIONS AND RECOMMENDATIONS

A summary of some of the most important conclusions and practical recommendations discussed in this report suggest that:

• Girls should be encouraged to get involved in sport and physical activity at an early age because such involvement reduces the likelihood of developing a number of deleterious health-related conditions. For example, active girls’ high caloric expenditure decreases their risk of becoming obese. (Introduction; Research Report, Section I)

• Specific mechanisms which enhance girls’ opportunities to be physically active must be developed and supported. Recreational, school-based physical education and sport programs are ideal ways to facilitate both health-related fitness and the acquisition of fundamental motor skills for a lifetime of activity. (Research Report, Section I)

• Involvement in sport and physical activity has tremendous potential to enhance a girl’s sense of competence and control. Therefore, leaders should incorporate cooperative as well as competitive opportunities to learn physical skills in a nonthreatening environment. (Research Report, Sections II and III)

• Parents, coaches and teachers must be aware of girls’ motives for participating in sport and physical activity. Girls participate not only for competitive reasons, but to get in shape, socialize, improve skills and have fun. All motives, not just those related to highly competitive activity, must be respected and validated. (Research Report, Sections II and III)

• Physical educators, exercise leaders and coaches are in a primary position to recognize disordered eating patterns among girls. These individuals must be knowledgeable about the physical and psychological signs and be able to make referrals to specialists as necessary. (Research Report, Section II)

• Girls and boys need to work and play together, starting from an early age. It is often easier for both sexes to play together and learn in small, relaxed groups where children know each other well and have the prerequisite skills. (Research Report, Section III)

• Coaches and physical educators should give girls equal access and attention. Girls as well as boys should play the important and interesting positions in a game and receive feedback to help improve their physical skills. (Research Report, Section III)

• Professionals must actively intervene in the face of discrimination. When adults observe inequities or gender stereotyping on the playing field or in the physical education classroom, it is often best to openly confront issues of prejudice such as sexism. (Research Report, Section III)

• Involvement in physical activity, exercise and sport promotes psychological well-being; the therapeutic use of physical activity and exercise for improving the mental health of adolescent girls goes beyond traditional treatment and mental health programs. (Research Report, Section IV)

• Physical activity and exercise have been shown to be a mood enhancer and an anxiety reducer, thereby acting as a natural, cost-effective intervention for the mental health of adolescent girls. (Introduction; Research Report, Sections II and IV)

DIRECTIONS FOR FUTURE RESEARCH

Because of the importance of sport and physical activity in the lives of girls, it is incumbent for us to continue to expand our scientific knowledge base regarding the physiological, psychological, sociological and mental health consequences of participation in these activities. A summary of some of the most important directions and agendas for future research suggests that:

• Research studies must be conducted to develop and implement motivational strategies encouraging physical activity during childhood and into adulthood. (Research Report, Section I)

• Research should establish guidelines for appropriate training levels. When establishing these guidelines, scholars should consider areas that are particularly critical for girls, such as the prevalence of overuse injuries and issues related to body composition. For example, specific guidelines for appropriate activity levels can prevent injuries due to excessive training and/or early specialization in one sport. Knowledge regarding appropriate levels of training can also minimize an undue focus on body composition (e.g., body image) that can lead to exercise addiction. (Research Report, Sections I and II)

• Research studies need to be designed that better distinguish between sport-specific or sport- general dropouts—versus sport transfers—to ascertain if girls are leaving organized sport entirely or simply sampling a variety of sporting activities. These investigations should collect and analyze participation statistics and conduct exit interviews with children who drop out in order to identify negative reasons for cessation and address them in future programs. (Research Report, Section II)

• We need to increase our research agenda to be more inclusive. For example, future research must be expanded beyond an analysis of highly competitive sport to include a broader range of activities (e.g., personal fitness) and settings (e.g., physical education classrooms). Additionally, studies should include participants from racially, ethnically, economically and ability-diverse backgrounds because gender interacts with these diversities in complex ways (Gill, 1993). (Research Report, Sections II, III and IV)

• Research studies must utilize an interdisciplinary perspective. For example, we need to adopt a biopsychosocial perspective that takes into account physical, psychological and social context variables simultaneously. We also need to develop “research teams” that enhance partnerships between scholars and practitioners. (Research Report, Sections II and IV)

• Future research should be guided by the principle that strategies for improving participation rates must also address the quality of the sport and physical activity experience for girls. (Research Report, Section III)

• Scientific studies should identify which factors influence exercise as treatment interventions. When using exercise as a treatment intervention to restore mental health for adolescent girls, we need to examine the impact of peer (same-sex and cross-sex) influences and individual versus group approaches. (Research Report, Section IV)

WHEN THE PRESIDENT’S COUNCIL ON PHYSICAL FITNESS AND SPORTS was established by Executive Order in 1956, few Americans could have imagined the surge of participation in physical activity and sport among girls and women over the last two decades. Millions of girls now participate in a rapidly expanding variety of physical activities, and female athletes perform feats that once were deemed physiologically impossible. Despite the startling speed of these recent changes, however, the explosion of women’s participation and ability is more accurately viewed as an acceleration of a centuries-long march toward greater physical freedom and athletic excellence.

During the nineteenth century, health reformers and educators included “female gymnastics,” walking, riding and dancing as key components of young women’s education (Vertinsky, 1994). In the countryside and towns, archery, tennis, bicycling, ice boating, roller skating, croquet, golf and dance became popular among girls and women. A “new model of able-bodied womanhood” emerged, which challenged traditional notions about female frailty and ladylike behavior (Verbrugge, 1988, p. 196). The integration of exercise and athletic activity into school curricula expanded during the twentieth century. Recreational athletics for girls became popular in the form of “play days” between 1920 and 1950 and competitive varsity sports such as basketball and track and field multiplied after World War II (Hult, 1994). The passage of Title IX in 1972 ushered in an era of coed physical education and greater opportunities for girls to play high school and college sports. The fitness revolution also grabbed the attention and allegiance of millions of girls and women during the 1970s and 1980s.

Physical Activity and Sport in the Lives of Girls: Physical and Mental Health Dimensions from an Interdisciplinary Approach presents an interdisciplinary portrayal of the connections among the physical, psychological, social and cultural aspects of physical activity and sport in girls’ lives. When viewed collectively, the research findings discussed here show how physical activity and sport impact the “complete girl”: that is, the many interrelated aspects of a girl’s life ranging from musculoskeletal and cardiovascular functioning, to psychological well-being, gender identity, relationships with friends and family and performance in school. Physical activity and sport offer girls more than gateways to fun, competition or an elevated heart rate. While the authors of this report are aware that girls’ experiences vary a great deal, the vision of the complete girl fosters a comprehensive awareness that exercise and sport are not just about physical movement but personal development, identity and values as well.

PARTICIPATION, OPPORTUNITY AND BARRIERS

American girls now participate in a wider range of physical activities and sports, and at more levels of competition, than ever before in our history. While Oregon girls learn to square their shoulders to the volleyball net, a group of girls play “four squares” in rural New Hampshire, an Arkansas teenager teaches hopscotch to her little sister, and Native American teenagers meet for lacrosse practice. As girls bounce and chatter through double-dutch jump rope in Bedford-Stuyvesant, in-line skaters glide through a Houston suburb. As an Ohio high school basketball team runs through drills, friends from DeKalb, Illinois, meet for an aerobics class. And women give gutsy performances while winning gold medals at the 1996 Summer Olympic Games in sports ranging from softball, soccer and basketball to gymnastics, track and field and swimming.

Females have become prime movers in the fitness realm. A recent nationwide survey conducted by the National Sporting Goods Association indicated that more women (55.4 million) than men (43.4 million) participate in several leading fitness activities—aerobic exercising, bicycling, exercising with equipment, exercise walking, running and swimming. A more specific breakdown reveals that an estimated 18.3 million women do aerobics, 26.5 million bike for exercise or mountain bike, 23.8 million exercise with weights, 45.2 million walk, 8.65 million run or jog and 32.6 million swim (National Sporting Goods Association, 1995).

Girls’ participation in school athletic programs and community-based programs is also mushrooming. Girls now comprise about 37 percent of all high-school athletes, representing an increase from one in 27 girls who participated in 1971 to one in three girls in 1994. The ratio for boys during this timeframe remained constant at one in two. In 1994–1995, 2,240,000 girls participated in high-school sports, compared to 3,554,429 boys, 37 percent and 63 percent respectively (National Federation of State High Schools Associations, 1995–1996). In terms of some specific sports, an estimated eight million girls under age 17 played basketball in 1994 (compared to 12.5 million boys) while 6.7 million girls played soccer. As more girls developed athletic interests and physical skills at the grassroots levels of competition during the 1970s and 1980s, participation in college and Olympic sports also exploded. Women now comprise 33 percent of all college athletes and approximately 39 percent of United States Olympic team members. Reciprocally, as more female role models become available for young girls to emulate, their interest and involvement in fitness and athletic activities will continue to grow.

Despite these gains, it is important to realize that women’s historical trek toward greater physical and athletic opportunity has been filled with barriers. In the past, various individuals have condemned exercise and sport as unladylike and eminent physicians warned women against overstrain and sterility. One of the authors of this report, sport sociologist Margaret Duncan, points out that stereotypes associated with traditional notions of femininity and masculinity exalted boys’ strength and athletic feats while equating girls’ athletic talents with “tomboyism.” Parents, coaches and teachers often encouraged boys to test their physical and emotional limits while ignoring or coddling girls.

Today, girls’ achievements in physical activity and sport remain overshadowed by the cultural prominence of men’s sports. In school and community-based programs, boys still receive a disproportionate share of opportunities to participate in exercise and sport. Male-dominated sports organizations remain mired in policies and beliefs that shortchange girls and women, and parents or advocates of girls are forced to wage expensive legal battles in the pursuit of gender equity. Indeed, it is unlikely that the large increase in girls’ athletic participation and growing cultural acceptance of physically active and athletic females would have occurred without the passage of Title IX (Birrell & Cole, 1994; Cahn, 1994a; Messner & Sabo, 1990). Pressured by the perceived threat of lawsuits or payment of legal fees, and pulled by increasing demands for greater opportunity for girls, Parent Teacher Associations and school administrators began to rethink traditional clichés like “girls just aren’t as physical as boys” or “sports are more important for boys than for girls.”

And finally, harsh economic conditions, prejudice and institutional barriers have limited the participation of many poor girls, girls of color and girls with disabilities. Ironically, where the real and potential health outcomes of physical activity and sport are probably most needed, participation rates and access to resources are most lacking. As the authors of this report repeatedly document, girls’ increasing participation and interest in physical activity and sport bode well for their health. Yet these positive national trends are being undermined by the growing numbers of adolescents who are becoming sedentary and obese, the substantial numbers of girls who are dropping out of sports, and the persistence of social and economic barriers that limit girls’ opportunities to develop physically active lifestyles.

UNDERSTANDING THE COMPLETE GIRL

Physical activity and sport are not simply things young girls do in addition to the rest of their lives, but rather, they comprise an interdependent set of physiological, psychological and social processes that can influence, and, in varying degrees, sustain girls’ growth and development. The interdisciplinary approach that underpins this report is designed to make more visible some of the connections among physical activity, sport and the rest of girls’ lives. Some examples of the broader linkages that are examined in the body of this report are highlighted below.

Psychological Well-Being

Within the traditional framework of psychoanalytic theory, nonconformity to traditional gender expectations was considered pathological. Hence, women’s interest and involvement in business, science, sport or other “masculine” activities were clinically suspect. In contrast, the review of psychological research presented in this report shows that physical activity and sport are apt to strengthen rather than worsen the psychological health of girls. The authors document a combination of psychosocial benefits such as self-confidence, self-esteem, higher energy levels and positive body image. It is important to note that these gains appear to be influenced by interactions with parents, who can either encourage or dampen a daughter’s interest and involvement. So, too, do persistent and narrow cultural prescriptions for appropriately “feminine” behavior erode the potential of physical activity and sport to enhance girls’ mental health. On the other end of the interdisciplinary spectrum, some of the biological and chemical processes associated with health and fitness concerns are also highlighted. And finally, two of the authors of this report, psychology of sport scholars Doreen Greenberg and Carole Oglesby, discuss the growing recognition among mental health professionals that exercise and sport can be effective treatment interventions for the significant number of girls who suffer from depression or anxiety disorders.

Obesity

The Surgeon General’s report on nutrition and health (Public Health Service, 1988) identified obesity as a major public health problem in the United States; subsequently, the Surgeon General’s report on physical activity and health (United States Department of Health and Human Services, 1996) identified physical inactivity as a serious public health problem nationwide. Aware of this concern, the authors of this report discuss a variety of factors associated with the rising rate of obesity among American adolescents. Social factors include the influence of television, dwindling requirements for physical education in the schools, and the steep sport dropout rate among adolescents. Related to physical health concerns, this report explores the physiological and epidemiological aspects of obesity such as the links between the development of hyperlipidemia, hypercholesterolemia, hypertension and diabetes, which in turn elevate risk for coronary heart disease. Finally, in her section on the psychological dimensions of participation, psychology of sport scholar Diane Wiese-Bjornstal stresses the need to help overweight or obese girls overcome social pressures and personal misgivings about physical activity so that they can become less sedentary.

The Female Athlete Triad

Several authors discuss the complex combination of psychological and physiological processes that operate in relation to the female athlete triad. In Section I, exercise physiologist Patty Freedson and psychology of sport scholar Linda Bunker document many physiological benefits of exercise and sport participation for girls such as potential gains in strength and aerobic power. It also appears promising that girls’ involvement in sport and exercise could effect increased immune functioning and the prevention of certain cancers in adult life. They also express their concerns about the “female athlete triad,” which refers to three interrelated health problems that are prevalent among some types of female athletes and some girls who engage in excessive exercise: eating disorders, exercise-induced amenorrhea and bone loss. Several authors demonstrate how these syndromes have complex psychological, physiological and social origins and profiles. For example, girls’ perceptions of their bodies are partly shaped by unrealistic media images that create false connections between a lean body type or “washboard abs” and subsequent success, sex appeal and self-mastery. The obsession with thinness can also be fed by a coach who demands weight loss from the athlete, or the desire to be attractive to boys and accepted by one’s peers. Because we are in the early stages of investigating this syndrome, the data we have are very limited. Female athletes most at risk should certainly be aware of the dangers, but we should not assume that the triad is limited to an athletic population (Lutter & Jaffee, 1996).

Sport and Academic Achievement

It is said that “the fish are the last ones to discover the ocean.” In Section III, Margaret Duncan illustrates how several research findings debunk the “dumb jock” stereotype that high school athletes perform poorly in the classroom. School administrators are often unaware of the positive interplay between high-school athletics and academic achievement as measured by grade point average, standardized achievement test scores, lowered risk for dropout and greater likelihood to attend college. On average, female athletes fare better academically than female nonathletes, though Caucasian and Hispanic female athletes are more apt to derive some direct educational gains than are their African- American counterparts (“Women’s Sports Foundation Report: Minorities in Sport,” 1989). Good physical and mental health are also correlates of academic performance and social adjustment. Hence, from an interdisciplinary perspective, it is likely that athletic participation is part of a mutually reinforcing array of physical, psychological and social processes that enhance the overall educational experiences and commitments of many girls.

In summary, understanding the role of physical activity and sport in the life of the “complete girl” is a dauntingly complex agenda. The mosaic of interdisciplinary findings and interpretations assembled in this report will deepen both insight and resolve in this regard.

POVERTY, RACE AND PHYSICAL ABILITY

Girls from economically disadvantaged backgrounds, girls of color and girls with disabilities can face unique obstacles in relation to physical activity and sport. Poor families cannot afford to invest in health club memberships, exercise machines and equipment for their daughters. Families of color, who are disproportionately poor, often cannot pay user fees or transportation costs to bring daughters back and forth between home and school. Fitness and sport are often seen as unattainable luxuries rather than potential resources. Dual-worker parents or single parents (most often mothers) sometimes depend on older daughters to cook or care for smaller children after school, thus curbing their involvement with extracurricular activities. Poor or working-class girls often work part-time jobs to help families make ends meet, thereby reducing the amount of time and energy available for exercise or sports. Parental perceptions of the benefits of exercise and athletic participation for daughters also vary by race and class. For example, one national survey found that Caucasian parents more often mentioned health- related benefits, character benefits and social factors than did African-American parents (“The Wilson Report: Moms, Dads, Daughters and Sports,” 1988).

Many of the problems girls of color experience in relation to physical activity and sport grow out of the same soil—poverty. Epidemiological research shows that exposure to violence, family fragmentation, substance abuse, sexually transmitted diseases and greater risk for unwanted sexual activity often share the common causality of poverty. Lack of physical activity and athletic opportunity can be added to this list. Economically disadvantaged girls of color are more likely to suffer from an unsafe and unhealthy environment. The simple act of walking or jogging may be problematic in neighborhoods where crime flourishes. Poor girls often do not have access to athletic resources, effective coaching and expert training. There is a lack of basic information about exercise, diet and sport. They are less apt to receive quality physical education and athletic training at earlier ages which, in turn, erodes the foundation for subsequent motor development. Because school and community athletic programs depend on tax dollars to thrive, capital flight from many urban areas is undermining the provision of adequate exercise and athletic opportunities for both minority girls and boys. The rising cost of liability insurance is also making it difficult for school districts, especially poorer ones, to provide quality athletic and intramural programs.

Little is known about the dreams, interests and physical activities of girls of color. Although women of color are often more visible in sport media, and in certain sports like basketball and track and field, they are underrepresented in sports such as swimming and tennis (Abney & Richey, 1992). During the early 1980s, African-American and Hispanic adolescent females comprised about 4.4 percent and 3.2 percent of high school athletes respectively, compared to 29.1 percent of their Caucasian counterparts (Melnick, Sabo, & Vanfossen, 1992). There is also indirect evidence that African-American and other ethnic minority females are less physically active than Caucasian females (King et al., 1992; Pate et al., 1995).

And finally, despite the accomplishments of the Special Olympics and Paralympics, few opportunities exist for emotionally or physically challenged adolescents to engage in exercise and sport. Differently-abled children are three times more likely to be sedentary than their able-bodied peers and the physical activity levels of children with disabilities drop precipitously during adolescence (Longmuir & Bar-Or, 1994). It should be noted that the authors of this report make only periodic references to socioeconomic status, race, ethnicity and physical disability. This is due not so much to choice, however, as to the fact that so little research has focused on these groups of girls.

WHAT RESEARCHERS DON’T KNOW CAN HURT GIRLS

This report is the first to assemble the bulk of existing research on girls’ involvement with physical activity and sport. However, because of the lack of available data and analysis, the authors of this report were unable to address in any depth some key aspects of girls’ experiences with physical activity and sport. Three emerging research concerns are briefly discussed below.

Unwanted Sexual Behavior and Adolescent Pregnancy

Adolescent pregnancy is a major social problem in the United States. Though the belief that sports can help many young girls avoid unwanted sexual behavior and pregnancy is widespread among coaches and athletes, precious little research has been done in this area (Sabo & Melnick, 1996). Two recent studies shed some initial empirical light on the hypothesized connections among exercise, athletics and adolescent girls’ sexual behavior. First, Brown, Ellis, Guerrina, Paxton and Poleno (1996) analyzed female adolescents’ responses to the United States Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention (1995) survey, “Health Risk Behavior for the Nation’s Youth.” The researchers found that the more days adolescent females exercised per week, the more likely they were to postpone their first experience with sexual intercourse. Second, preliminary analysis from a study of adolescents from western New York (an area with one of the highest rates of adolescent pregnancy in the United States) indicated that higher rates of athletic participation among adolescent females were significantly associated with lower rates of both sexual activity and pregnancy (Sabo, Farrell, Melnick, & Barnes, 1996).

Sexual Harassment

Sexual harassment is experienced by approximately 31 percent of female high school students (American Association of University Women Educational Foundation [AAUW], 1993). Sport scholars have recently begun to study the prevalence and social-psychological dynamics of sexual harassment in athletic settings (Sabo & Oglesby, 1995). Many key questions need to be addressed. For example, how do female athletes perceive and react to sexual harassment from boys and adults? Do higher self-esteem and physical prowess fostered by sports help females to be more assertive with inappropriately invasive males than their non-athletic counterparts? Additional research needs to be done on the ways that athletic participation may empower girls to more effectively cope with sexually hostile situations.

Exercise and Sport as a Family Asset

Regretfully, little research has focused on the ways that exercise and sport promote interaction and insight between parents and children. As is the case with sexual harassment, many important questions in this area remain unanswered. Do parents look to sport to provide after-school activities that keep daughters physically active, socially engaged and off the streets? To what extent do physical activity and sport help parents nurture moral development and values in their children? In what ways can parents effectively encourage their daughters’ involvement with physical activity and sport? Clearly, more investigation of the interdependencies among physical activity, sport, families and schools is needed.

CONCLUSION: EXPANDING THE RESOURCE

This report will fuel the growing awareness that physical activity and sport are enormously important in the lives of girls. Perhaps this message is being sent by girls themselves who are, as the saying goes, “voting with their feet,” and entering the realms of fitness and sport in vastly increasing numbers. In contrast to the nineteenth century naysayers who decried strenuous exercise and athletic participation for women as dangerous and unladylike, today, educators and public health advocates recognize the overall benefits for girls’ physical health and emotional well-being. As health care costs continue to escalate, and pressures on the American health care system to provide quality care intensify, the logic of preventive health strategies that involve physical activity and sport becomes economically salient.

The overall vision that emerges from this report frames physical activity as a developmental aid and public health asset for girls and, by inference, for boys as well. Physical activity can serve as a social and cultural intersection where adolescents, parents and caring adults can come together in mutually supportive ways. The aerobics class, fitness run or basketball court are safety zones where young girls can hang out together, test and challenge themselves, learn about competition, develop physical fitness components such as cardiovascular endurance, strength and flexibility, and have fun all at the same time.

The real and potential benefits that physical activity and sport have to offer girls, their families and communities, however, continue to be stymied by several factors. Economic and cultural barriers block wider participation, especially for poor girls and girls of color. Despite increasing interest and participation rates, physical activity and sport remain underutilized resources for the many girls who are mired by sedentary lifestyles or dissuaded from getting involved because of gender stereotypes, discriminatory practices and lack of opportunity. There are also appreciable numbers of girls for whom athletic participation is associated with illness, injury and addiction to exercise rather than with physical and mental well-being. And finally, there needs to be more systematic research on the numerous ways that physical activity and sport influence girls’ lives. Simply put, too little research has been done in an area where girls have too much to gain. For this reason, each of the authors has listed priorities for future research at the end of their respective sections.

This report concludes with a list of policy recommendations. The information and analyses gathered here hold implications for parents, educators, coaches, athletic administrators, public health officials and lawmakers. There is more at stake in the struggle to expand girls’ physical abilities and athletic opportunities than learning to do jumping jacks or winning and losing games. Future policy decisions need to be grounded in the broader understanding that girls’ involvement with physical activity and sport is just as much about physical vitality, emotional well-being, community health and educational opportunity as it is about who runs the farthest or scores the most points.

MUCH IS KNOWN FROM RESEARCH ON THE EFFECTS OF EXERCISE and sport participation on adolescents and adults. However, the majority of this research was conducted on males, or focused on comparisons between boys and girls, with little research focusing exclusively on females. The present review must therefore include research on adults and males, as well as the biophysical effects of physical activity and sport on girls and the potential impact of these experiences on their maturation and adult lives.

The acquisition of fundamental motor proficiency, which is directly linked to physical activity, is an important goal for early childhood. Not only must children learn to control their bodies in space, they also need to acquire the fundamental skills which will aid daily living, vocational pursuits and recreational/leisure activities. These skills are interdependent with health-related physical fitness and must be considered in any discussion of the biophysical effects of physical activity on girls.

It is important that activities in childhood include both the motor and health aspects of physical fitness. Both health-related fitness and motor skill development are important because: (a) children need a reasonable level of motor skill proficiency to participate in activities that build endurance, power and strength, and (b) they need reasonable levels of fitness to engage in exercise and sport activities which will provide them with physical activity as adults. Recognizing the need for both motor skill development and adequate fitness is critical because the benefit of lifetime participation in physical activity has an impact on psychological aspects (see also Section II: Psychological Dimensions), social aspects (see also Section III: Sociological Dimensions) and the mental health of young girls and women (see also Section IV: Mental Health Dimensions).

The simultaneous acquisition of both motor and physical fitness begins in early childhood, as children use movement as their mechanism to learn about their world. It continues in school where all children should participate in daily physical education activities which set both the pattern of physical activity and the fundamental skills to be successful and happy when participating.

Physical activity has long been recognized for its effects on the maturing child. However, one of the challenges of interpreting research on children is the difficulty of differentiating between the changes in physiological functioning which may be affected by regular exercise or strenuous training, and those effects which are the natural result of maturation. This problem is compounded by the traditional use of control groups to help differentiate between the effects of the exercise intervention and those of normal growth and development, because most children are already quite active (Bar-Or, 1989). This makes the experimental designs more complicated, the exercise interventions more intensive than those which would be adequate for adult participants, and the interpretation of the data more challenging for the researcher.

The biophysical changes which result from exercise and training may shift in the same direction as those which occur due to maturation, or they may change in the opposite direction. For example, peak anaerobic power increases due to both maturation and physical training. Similarly, decreases in oxygen cost of moving are also caused by both maturation and physical training. With respect to biophysical changes in the opposite direction, the body’s ability to use oxygen (i.e., anaerobic threshold, percent V. O₂ max) decreases due to maturation but increases as a result of training (Bar-Or & Malina, 1995).

It is possible to consider the known effects of physical activity in many different ways. The following information clusters the research into three categories related to biophysical considerations: benefits for girls, potential deleterious effects and potential long-term effects related to disease prevention and quality of life.

BENEFITS OF PHYSICAL ACTIVITY FOR GIRLS

Research on the biophysical impact of exercise on children and adolescents is quite extensive although, as previously mentioned, investigations focusing exclusively on girls is limited. The following information addresses those benefits specifically relevant to girls. We focus in particular on benefits related to power (i.e., aerobic power or endurance and anaerobic power), strength, weight management and health-related issues such as immune function effects and reproductive maturation.

Strength

Muscular strength is defined as the ability to generate force and includes dynamic or isotonic strength (i.e., the ability to generate force through a range of motion) and isometric strength (i.e., the ability to generate force at a single point in the range of motion where muscle length does not change). With respect to the maturing female, girls grow stronger as they mature, making it difficult to assess whether changes are the result of maturation or physical activity levels. However, several studies have found that short-term training programs can produce increases in muscle strength in children (Grodjinovsky & Bar- Or, 1984; Sale, 1989). Pfeiffer and Francis (1986) have suggested that the relative gain in strength due to exercise is similar for all children, whether they be prepubescent, pubescent or postpubescent. According to Malina and Beunen (1996), “prepubescent” is defined as the absence of development of secondary sex characteristics, “pubescent” is initial and continued development of secondary sex characteristics, and “postpubescent” is adult or mature state of development for secondary sex characteristics. Increases in physical activity and short-term training programs can produce positive changes in several forms of “strength-related” factors, including anaerobic power and muscle endurance.

Maturation-related strength increases at a linear rate for most girls up until about age 14. Beyond that point, the rate of increase slows and for sedentary girls may actually decrease (Blimkie, 1989; Parker, Round, Sacco, & Jones, 1990). However, systematic physical activity can produce marked improvement in strength for girls, probably due to the improvement in motor unit activation and coordination (Sewall & Micheli, 1986; Wilmore, 1974).

Power

The concept of power is related to the capacity to do work per unit time and is directly related to both muscular strength and cardiovascular functioning. The following discussion of power includes both aerobic power which is necessary for endurance activities and anaerobic power which is necessary for short-term, high-energy– demanding activities.

Aerobic Power and Endurance Performance

Cardiorespiratory fitness represents the maximal transport of oxygen, which is a function of the product of heart-rate and stroke volume (i.e., cardiac output), the oxygen-carrying capacity of the blood (i.e., hemoglobin content) and the maximal arterio-venous oxygen difference. Aerobic power is typically measured by V. O₂ max as determined by either cycle ergometry or treadmill exercise. Expressed as an absolute measure (l • min^-1) or as relative to body mass (ml • kg^-1 • min^-1), measurements of aerobic power are extremely reliable in both children and adults if standard criteria defining maximal responses are used and if subjects—children and adults—participate with maximum effort.

The general pattern of change in absolute aerobic power (l • min^-1) for girls suggests that it increases with growth prior to adolescence, but in the absence of systematic exercise, it steadily declines into adulthood. Summarizing cross-sectional data from several studies testing children of different ages, Armstrong and Weisman (1994) reported a decrease in absolute aerobic power in adolescent girls 13 to 15 years of age.

Despite the apparent decrease in absolute aerobic power in females ages 13 to 15, the overall rate of increase in treadmill absolute aerobic power for females between the ages of eight and 16 was approximately 12l • yr^-1. Examination of treadmill-relative aerobic power across age revealed a steady decline for females (Armstrong & Weisman, 1994). Aerobic power relative to body mass (i.e., V. O₂ max expressed as ml • kg^-1 • min^-1) averaged 50ml • kg^-1 • min-1 for girls at eight years of age which decreased to approximately 40ml • kg^-1 • min^-1 by age 16. This trend was not observed for males across the same age span; they maintained a relatively stable aerobic power of approximately 55ml • kg-1 • min^-1 (Armstrong & Weisman, 1994).

This decrease in aerobic power is most apparent at the time of puberty when there is an increase in body fat. Additionally, cross-sectional data indicate that inactive children have lower V.O2 max than normally or highly active children (Malina & Bouchard, 1991). Fortunately, this decline in aerobic power can be reversed with aerobic training (Rowland, 1989). Both short-term and long-term training programs seem to result in about the same improvements in maximal aerobic power among sedentary older children and adults (Bar-Or & Malina, 1995; Pate & Ward, 1990).

Aerobic power and endurance performance are closely related in adults, but seem to be dissociated in adolescents. Specific to adolescent females, aerobic power expressed relative to body mass declines through normal growth and development, yet endurance performance (e.g., timed mile run) improves. For example, time to complete a one-mile run improves by approximately 15 percent in females between eight and 17 years of age, despite a 20 percent decrease in relative aerobic power (Rowland, 1989). Nonetheless, it should be pointed out that regular exercise can increase oxygen uptake and diminish some of the decline that would otherwise occur. Improvements in running economy that occur with maturation most likely explain the dissociation between aerobic power and endurance performance in adolescence.

Anaerobic Power

Anaerobic power, or the capacity to perform strenuous activities in short bursts of time, does not rely as extensively on the cardiovascular system. For most girls, anaerobic power (such as that required to do a vertical jump) increases throughout early childhood, but decreases in adolescence and young adulthood. However, anaerobic power improves in children who exercise, especially those who train systematically. Gains as a result of training for adolescents (10 to 13 years) range up to about 20 percent.

Weight Management

Juvenile obesity is “arguably the most prevalent chronic illness among children in North America and represents an immense public health challenge” (Bar-Or & Malina, 1995, p. 110). A child is considered obese when his or her weight-height ratio is 20 percent or more above the upper limit of the desirable weight as assessed by primary care physicians and pediatricians using standard growth charts (Insel & Roth, 1991).

According to data from the National Center for Health Statistics (1991), approximately twice as many children are overweight today compared to children in the 1960s (Blair et al., 1996). It should be noted that juvenile obesity is particularly prevalent in girls from highly urbanized areas (Dietz & Gortmaker, 1984), some ethnic groups (e.g., Hispanic Americans, Pima Indians [King & Tribble, 1990]) and those with disabilities (Dietz, 1995).

Problems with weight control occur when the caloric intake does not match the caloric expenditure. Though the major problem for obese individuals may be the nature of the calories consumed (especially excess fat intake in terms of the percent of the total calories), exercise is an important adjunct in weight control for high-school girls (Wells, 1991; Moody, Wilmore, Girandola, & Royce, 1972) and for women 18 and over (Miller, Lindeman, Wallace, & Niederpruem, 1990). Exercise has the effect of increasing caloric expenditure, and also seems to protect fat-free mass while promoting the loss of fat mass (King & Tribble, 1990).

For the general population of girls, their daily routine provides an adequate balance of physical activity and caloric intake. However, to assist the obese child, it is essential that a multidisciplinary program include nutrition education and increased physical activity both during weight loss and afterward. Many of these programs are provided in physical education programs within our schools and, as Ward and Bar-Or (1986) have suggested, this is the most practical way to combat this national problem.

Vogel (1986) presented an extensive review of physical education programs and concluded that daily programs can produce changes in body composition (i.e., percent lean versus fat mass), aerobic fitness, balance, endurance performance and lipoprotein profiles (especially for children with elevated lipoproteins). In addition, when programs are designed to promote motor skills and aerobic fitness, changes in skinfold thickness may occur (Simons-Morton, Parcel, & O’Hara, 1988). The key to controlling obesity is a combination of caloric reduction and increasing caloric expenditure. However, when controlling obesity, one must keep in mind the concurrent need to support the growth process and to maintain nutritional adequacy.

Immune System

The relationship between immune function and physical activity must be discussed in relation to the intensity of the activity (Liesen & Uhlenbruck, 1992). A great deal of research reports that low- to moderate-intensity training enhances immune function with increases in levels of interleukin-1 and interferon and increased numbers of natural killer cells, circulating lymphocytes, granulocytes, monocytes and phagocytic macrophages (Kramer & Wells, 1996). However, with exhaustive or very intense and prolonged training, there may be a depression of immunological function. Overtraining may depress the levels of immunoglobulin in blood and saliva, reduce the responsiveness of T-lymphocytes to antibody synthesis and increase the risk of infectious and viral diseases (Newsholme & Parry- Billings, 1994).

The T-lymphocytes and natural killer cells seem to function as a tumor inhibitor to retard the growth of cells which have been genetically damaged (i.e., cancer). Similarly, monocyte and macrophage function also decreases the likelihood that aberrant cells will be facilitated or that metastases will occur. Thus it appears that moderate intensity exercise may have a positive effect in retarding diseases such as cancer or those caused by viruses such as colds or influenza (Newsholme & Parry-Billings, l994). See the section below entitled “Potential Long-Term Effects” for a more detailed discussion of this topic.

Research on the effects of exercise on the immune system is mixed, depending on both age and intensity of physical activity. There is some evidence that increased physical activity produces moderate immune response suppression, but the clinical importance of this response is debatable (Calabrese, 1990). For example, adolescent athletes have been found to be more susceptible to infections than nonathletes (Shephard, 1984), but this may also be true for other children who participate in group activities in close proximity to one another (e.g., band, drama). In contrast, in a prospective study, Osterback and Ovarnberg (1987) found no difference in immune function between 12 year-old athletes and nonathletes.

Reproductive Functioning: Menarche

There are many anecdotal reports of the positive influence of regular physical activity on the menstrual cycles of pubescent girls. Many girls report less physical distress associated with the cycle and increased periodicity (i.e., regularity) when moderate physical activity is part of their lifestyle.

For many years it was believed that delayed onset of the menstrual cycle (i.e., menarche) was the result of sports participation by young female athletes. This conclusion was based on the observation that menarche occurred later in athletes than nonathletes. An alternative explanation was offered by Malina (1983) who suggested that young females who mature early are socialized away from sports participation. For the young female athlete, late maturation accompanied by delayed fat deposition favors athletic success and may result in a type of self-selection. In other words, delayed menarche may result in continued participation in competitive sport (Stager, Wigglesworth, & Hatler, 1990). Wells (1991) summarized data from several studies and reported the age of menarche for girls participating at different competitive levels: nonathletes = 12.29 years, athletes = 13.02 years, college athletes = 13.05 years, national-level track and field athletes = 13.58 years, Olympic athletes (Montreal) = 13.66 years, national-level middle-distance runners = 14.10 years, Olympic volleyball athletes = 14.18 years and national-level runners = 14.20 years. It should be noted that these data were collected retrospectively and may be influenced by recall bias in which athletes remember later menarche.

Delayed menarche is a particularly complex issue which could have both positive and negative consequences. Historically, delayed menarche, which is often found in female athletes who train at high levels, was viewed as a problem because it supposedly compromised fertility (Frisch, Wyshak, & Vincent, 1980). More recently, concern about delayed menarche has focused on its impact on peak bone density. Menarche is associated with an increase in circulating levels of estrogen. Estrogen is a necessary hormonal trigger for increasing bone density in