Since 1987, McNitt-Gray, director of the Department of Exercise Science’s biomechanics laboratory, has studied the dynamic takeoffs and landings of world-class gymnasts. Working on behalf of the U.S. Olympic Committee, she hopes to improve athletes’ performance, reduce injuries and increase equipment safety.
This summer, the USC exercise scientist – who holds joint appointments in biomedical engineering, biokinesiology and physical therapy – will team up with an international group of scientists to film the gymnastic events at the 1996 Olympic Games in Atlanta. The Olympic Science Project will capture the best jumps and landings, examine them frame by frame, and use the data to help other athletes train.
“I’ve seen too many people get injured, and I think a lot of these injuries can be prevented,” said McNitt-Gray. “Most of them occur during the impact between athlete and apparatus, particularly the landing mats and the spring floor.”
The problem can be approached in two ways. One, improve the athlete’s ability to absorb energy at contact, so musculo-skeletal structures do not get injured. Two, improve the surface so that it, rather than the body, absorbs the shock. McNitt-Gray has explored both options.
She and her researchers have monitored male and female gymnasts at the U.S. Olympic Training Center in Colorado Springs, Colo., as well as male decathletes at the Olympic Training Center in Chula Vista, Calif. She has worked with gymnasts David St. Pierre and Scott Keswick, and with decathletes Dan O’Brien and Dave Johnson, among others.
Widely recognized as the premier U.S. researcher in her field, McNitt-Gray has observed and quantified nearly 100,000 takeoffs. Whether it’s the vault, the pommel horse, the uneven parallel bars, the high jump or the long jump, McNitt-Gray looks at two elements: how much force is being exerted, and in which direction the force that is being exerted.
“Our aim is to identify the underlying mechanisms humans use when preparing for impending collision, for distributing load during impact, and for achieving equilibrium after contact with the landing surface,” she said. “Better understanding of the biomechanics and neuromuscular control prior to, during and after interaction with the environment contributes to improvements in performance and reductions in injury.”
Her team monitors muscle-activation patterns much as an electrocardiogram technician monitors electrical activity of the heart – by attaching electrodes to various sites on the athlete’s body. The electrical activity of the muscles is amplified, digitally sampled and stored for computer analysis.
“We measure the forces with a force plate, which is like a very, very sensitive bathroom scale,” McNitt-Gray said. “We’re looking for muscle activation patterns – when the muscles fire, when they turn on and off.”
These biomechanical readings help coaches fine-tune an an athlete’s approach, takeoff and landing so that he or she can run faster and jump higher with less chance of injury.
“A gymnast may be experiencing 14 times his or her body weight in force when taking off,” McNitt-Gray said. “It’s important to know how much force is involved, and in which direction the force is being applied, because certain bones and soft tissues can handle force in certain directions better than others.”
The sport of gymnastics has become increasingly demanding as it has attracted more athletes, resulting in stiffer competition. With each successive Olympics, routines become more complex and require better mechanics.
“Gymnasts are now tumbling forward as well as backward, because more points are being awarded for forward-rotating skills,” McNitt-Gray said. “They tend to take steps when they land, and they prepare for contact according to how they are moving prior to contact. Also, they distribute at the ankle and the hip differently if they land forward. This has both injury and training implications.”
McNitt-Gray speaks from experience. While earning a degree in mathematics at Miami University in Oxford, Ohio, she competed on the gymnastics team and played varsity field hockey. After graduation, she earned a master’s in biomechanics at the University of North Carolina at Chapel Hill, and a Ph.D. in biomechanics at Pennsylvania State University.
At USC, McNitt-Gray and her students have established an experimental biomechanics research and teaching facility. The research projects have been funded in part by the U.S. Olympic Committee, the National Science Foundation, the National Institute on Aging, the National Collegiate Athletic Association, the International Olympic Committee Medical Commission, the American Association of Retired Persons and a number of national governing bodies of Olympic Sports.