Today an estimated 24 million Americans, 90 percent of them women, jump through steps and stretches to Donna Summer-esque music that leaves them sweaty, exhausted and convinced that they are perfecting their bodies. But Peter and Lorna Francis, physical educators at San Diego State University, saw signs of trouble two years ago when they studied 135 aerobics instructors. To their dismay, Peter, 47, a professor of biomechanics, and Lorna, 32, an aerobics instructor for 10 years, found that 76 percent of the instructors had sustained injuries and were ignorant of basic safety precautions. These findings have now been incorporated into new guidelines issued by the American College of Obstetricians and Gynecologists (ACOG). Concerned that women may be sustaining unnecessary injuries, the College has approved a videocassette (Balanced Fitness Workout, $39.95) of safe exercises. Peter and Lorna Francis discussed their concerns with correspondent Nancy Faber.
Is aerobic dance really dangerous?
It can be. It's an effective tool to improve fitness, but like all tools, it can be dangerous in the wrong hands.
You found three out of four aerobics instructors suffered injuries. Why is that?
Dance instructors often teach too many classes—sometimes seven a day, according to our survey. They should be teaching rather than performing in front of their classes. They work hard, have incredible enthusiasm and high performance standards, but it can result in injuries to them and their students.
What other kinds of injuries have begun to crop up?
We're seeing injuries to the shin, foot, knee, hip and lower back. Any activity that involves repeated and vigorous pounding of the feet on the ground produces some kind of injury. Aerobics involves a whole family of exercises done standing and bending at the waist. In bending forward, the compression on the discs of the spine is uneven and is potentially higher in fact than what most people can tolerate. Then, if you twist from side to side, you add a grinding action on the spinal discs.
What else can happen?
Indiscriminate flinging of the arms or deep knee bends—we call them ballistic movements—put stress on the joints and can cause muscle micro-tears. We've seen a case in which an excessive number of arm lifts produced a shoulder tear usually seen only in professional baseball pitchers.
Can equipment help prevent injuries?
Shoes are important. In aerobic dance, the point of impact on the floor is under the ball of the foot. That's one reason not to wear a running shoe, which is designed to take the impact on the heel and has very little absorption in the front. Running shoes also have heavy treads or waffles. In aerobics you need a light tread so the foot can move in any direction.
How important are floors?
Very. The worst floor is carpet over cement—which only gives the illusion of being cushioned. The best floors are hardwood over air space or floors that have a sponge layer beneath them.
Are many students injuring themselves?
One study done simultaneously with ours estimated that 43 percent of students get injured. It may be even higher because often people drop out when they get hurt.
What's the proper amount of time you should spend in an aerobic dance class?
Only people in superb physical condition should go a full hour. We suggest the most you should spend on the intense portion of the class is 30 minutes. Exercise on alternate days and no more than four times a week.
Why are instructors so demanding of themselves and their students?
Aerobics instructors are largely self-taught. At health clubs, they work at a very high intensity, and many who are from ages 21 to 25 feel that abuse is good for them. Often students demand a hard, driving session. Instructors are afraid they'll lose their clientele if they conduct more moderate exercises.
What impact has Jane Fonda had?
Fonda has done a lot for exercise. She's a very attractive lady, and many women have become interested in exercise because of her books and tapes. But she's not an exercise expert. In her latest tapes she is improving; she has used consultants more. We regard her as a motivator more than an educator.
Is there any move to certify instructors?
Instructors today are still not required to have training or be licensed. But later this month at the International Dance-Exercise Association (IDEA) Convention more than 1,000 instructors will voluntarily take the first national dance exercise certification exam.
What are the most important do's and don't's?
Ask about the instructor's training. Check out the floor. Get the right shoes. And never exercise with pain or an injury. Safe aerobics don't have to be boring.
"You must work hard, sweat hard and get sore," exhorted Jane Fonda in her Workout Book In 1981. Millions followed her advice with a vengeance. And now, according to a new study, they may be getting badly hurt.