In the midst of the recreation explosion in the U.S., in which novice joggers care as much about their hamstrings as $1 million basketball players, physicians are turning to a new specialty: sports medicine.

Responding to the physical and psychological needs of a growing number of athletes and would-be athletes, the medical community is becoming more aware of its responsibility in helping to keep Americans running.

In sports medicine clinics and offices, physicians are examining sports-related injuries: how they happen; why they happen and whether they be prevented.

The ultimate goal is to improve the general health and fitness of the athlete. For this reason, the medical community has broadened its research to include studies on equipment, the role of trainers and effects of diet and drugs on performance.

In dozens of interviews with The Washington Post over the past three months, physicians across the country shared their theories and experiences in the field of sports medicine. They also discussed ethical and philosophical issues, such as the relationship between team physicians and athletes, coaches and owners.

Sports medicine is not likely to become a full-fledged specialty offered by medical schools because it embraces knowledge of so many medical disciplines and the four-year medical school curriculum is already overcrowded, said Dr. Allan J. Ryan, a Minneapolis surgeon who is editor-in-chief of the magazine, The Physician and Sportsmedicine.

Most athletic injuries are musculoskeletal, making the orthopedist the physician most likely to be involved in sports medicine cases. The cardiologist also plays a major role because of the part exercise plays in preventing heart attacks and rehabilitating heart attack victims.

The pediatrician is involved, too, because of the large number of children participating in athletics at a time when their bones are still growing and potentially restrictive diseases are being detected. The ophthlamologist is concerned about eye care, as is the dentist about teeth and facial disfigurement.

Add to this array the osteopath, the dermatologist, the allergist, gynecologist, podiatrist, nutritionist, psychiatrist, urologist, general surgeon and, of course, the general practitioner.

Trainers have become more crucial in the past several years, but because of financial reason, too few high schools employ them. Most colleges with even a slightly ambitious sports program have a trainer, but not always a certified one. Most professional sports teams have trainers.

Since the late 1960s, sports medicine clinics have been springing up al over the country. Not surprisingly, they are usually located in large citics with a number of professional sports teams and on university campuses where sport is big business.

"A sports medicine clinic is not a clinic as such. It's a doctor's office which essentially treats patients and their injuries that often tend to be sports-related." said Dr. Robert Nirschl, an Arlington orthopedist who heads the sports medicine committee of the Medical Society of Virginia.

Nirshl, whose office operates a nearby physical therapy unit for patients, estimates about half his practice is sports-related. Some of his patients are professional athletes, others amateurs and still more are victims of leisure time activities.

"Sports medicine is very helpful in treating the average patient. A very good example of that may be an 80-year-old lady who falls down and breaks her hip and we replace that hip joint," Nirschl said.

"So we find ourselves doing a much better job for those patients also, from the point of view of strength, flexibility and helping them with equipment - whether it's a back scratcher because the shoulder isn't flexible enough to let them reach the back or a hip joint."

Nirschl's example illustrates what many physicians believe to be the essence of sports medicine - the improvement of health for the general population.

The philosophy is incorporated in the definition of sports medicine by the American College of Sports Medicine, based at the University of Wisconsin. The organization has about 4,000 members, drawn from the medical, paramedical and lay communities.

"Sports medicine is a perspective, easier to describe than define." the college says. "It involves sports but is not limited to medical supervision. Essentially it is the study of the health implications of man in activity."

The college also stresses the need for research and the sharing of that research. The college was founded in 1954, executive director Gary Jenks said, by 16 physicians "concerned about the lack of awareness by general practitioners for treating sports injuries.

Although there is a great deal of independent research conducted at sports medicine clinics and by individual physicians in this country and others, many physicians interviewed for this series said far too little of it is shared. There is no nationally recognized clearing house for sports medicine data.

"The people who are doing research on human performance and fitness are not really concerned that coaches and athletes are not getting the results of that research which could be of assistance." said Dr. G. R. Greenwell chairman of the Amateur Athletic Union's sports medicine committee.

"The athlete is willing to be the 'laboratory' so we can determine what it takes to be 100 per cent healthy, not just 97 per cent . . . to become the guinea pig for the rest of the population, so to speak," Greenwell added.

While the athlete may be the model by which to gauge the fitness of the rest of the population, the athlete, especially professional athletes, have their own peculiar needs. said Dr. Fred Allman Jr. an Atlanta orthopedist who opened a sports medicine clinic in 1960.

"I felt there was a growing need for a subspecialty in sports medicine . . . that the athlete was different from other patients," said Allman. who has taken care of hundreds of high school and college athletes and co-edited with Dr. Ryan the text, "Sports Medicine."

"Unless a doctor recognized that athletes were different and acted accordingly, the athlete was not receiving the care he should," he said.

"The athlete is different from others because when he returns to play, he immediately re-exposes himself to the sitution which caused the first injury. A banker who sprains his wrist would have no trouble carrying on his business. But a pole-vaulter who pulls a hamstring couldn't . . . An injury may be totally incapacitating to an athlete, but wouldn't bother anyone else."

The millions of dollars involved in professional and collegiate sports annually has forced more attention on preventive medicine - which encompasses equipment as well as excercises and training to prevent certain injuries.

"In a week during the season, there are probably more football injuries to high school players than there are players in the NFL," said Dr. James Garrick, medical advisor to the joint safety committee of the NFL and the NFL Players Association.

The NEL and NELPA have been studying for years the incidences of injuries resulting from the use of certain equipment and playing field turfs. The joint safety committee is currently surveying equipment players use, don't use and why, Garrick said.

In some cases, the equipment may be too good, causing serious injuries to an opponent on contact. Conversely, some equipment if inadequate or not worn because the player feels it is too restrictive.

Being the competitive lot that they are, equipment manufacturers are trying to perfect their products as used from the pee-wee to the professional leagues. But, nobody is designing equipment for women, says Dorothy V. harris, Ph. D., director of the Center for Women and Sport at Pennsylvania State University.

"Unless there is a liability suit, there's going to be no change," Harris said of the practice of having women adapt to men's equipment, which is often not suitable to the female anatomy.

An ever-escalating number of suits against equipment manufacturers and whopping damages awarded in some cases have forced some companies to shut down and others to discontinue making some equipment.

Six of 13 foot ball helmet manufacturers in business several years ago have stopped making helmets. Gymnastic equipment companies have been stampeded with suits, most stemming from trampoline injuries.

The possible threat of suits has prompted some school systems to cancel some sports because insurance is either unavailable or costs too much.

The increasing frequency with which Americans have taken to the courts has had its effects on sports medicine, team physicians in particular.

At the high school and college level, the physician's decision is almost always the final word on whether a player is taken out of a game after an injury.

At the professional level, six figure salaries and second-stringers foster the playing-with-pain ethic. The physician does not always prevail, but those interviewed for this series said they would quit being team doctors if their advice were ignored.

The multimillion-dollar payrolls involved in pro sports virtually mandate getting the best care and many teams have a number of specialists available for treatment at games and consultation at other times.

For economic reasons, says Dr. Allan Ryan, many high school teams get anybody they can.

"An eye doctor or urologist may have a boy on the team and the coach may ask the doctor (to be team physician)," Ryan said. "So the question of liability is of increased concern to the physician, generally."

There are also ethical considerations, the confidential relationship between doctor and patient.Where do loyalties lie and what factors may change them?

"Most enlightened clubs allow the doctor to determine when and how the player is to be brought back . . . if you're going to get maximum recovery or maximum return, the player must be guided by the doctor," said Dr. Robert Kerlan, medical director of the National Athletic Health Institute in Los Angeles.

"The players are better informed now and realize we can pretty well get them back in shape. If a player has something we can help him with and get him back faster, it's to his advantage to come to us.

"Most of the players now are represented by lelal counsel or an agent and they are aware of what's going on. A player wouldn't allow himself to be used if he wasn't up to par."