I developed the habit of taking seven spin classes a week during my summer break. It's been great for my endurance, but my muscles are looking bulkier in ballet. Is spinning bad for dancers?
—Ashley, Miami, FL
The answer depends on your body's composition. All of us are born with a mix of fast- and slow-twitch muscle fibers. If you are muscular, you most likely have more fast-twitch fibers responsible for short bursts of strength, speed and a dynamic jump. Unfortunately, these fibers are 30 to 40 percent bigger than their slow-twitch counterparts and are more likely to bulk up when you engage in high-impact aerobic exercises, such as jogging, or activities like spinning that overwork the quadriceps and buttocks. In contrast, dancers who have more lean slow-twitch fibers, which are responsible for endurance, can work for longer periods but often lack tone and require weight-lifting exercises to build muscle mass.
It's great that you are creating a better balance by focusing on the slow-twitch fibers that increase your aerobic capacity. But to avoid bulking up, consider switching from spinning to swimming, which has no impact, or the elliptical machine, which has minimal impact and spreads the workload across your arms and legs.
An effective cross-training program during breaks from dance alternates aerobics three times a week with strength and stretching sessions and a day of rest. In your case, Pilates will help you acquire a leaner look by working the slow-twitch fibers. You can find out which aerobic exercises stress different body parts in my book The Dancer's Way: The New York City Ballet Guide to Mind, Body, and Nutrition. Note: Spinning can strain the kneecaps, so dancers with troublesome knees beware.
Send your questions to Dr. Linda Hamilton at firstname.lastname@example.org.