1. The Jump Where You Land Like a GirlThe move: Box jumps (hopping up and down with both feet on platforms of various heights)
The risk: These trendy CrossFit moves (now coming to a gym near you) can be a great way to build power, says Vonda Wright, MD, a Pittsburgh-based orthopedic surgeon who specializes in injury prevention and mobility. However, they're notorious for causing injuries to the knee or Achilles tendon. Landing properly requires excellent form, and that can be tough to maintain when you're doing several in a row, says Wright. Most men land with their butt sticking out and their knees facing forward and deeply bent, which absorbs impact. But, Wright says, women tend to land with their legs straighter and their knees closer together, which can be hard on the joints (it could even cause a ruptured ACL).
The fix: Wright says to start with standing broad jumps until you perfect your form and are able to land without wobbling. Increase the height very gradually, and consider stepping down to the ground instead of jumping.
2. The Hand Position You Learned to Do Wrong in Grade SchoolThe move: Bench presses
The risk: These strengthen the shoulders, arms and chest, but Wright says she often sees people positioning their hands too far apart on the bar. The reason, she says, is that many of us started doing push-ups in PE class (usually for the President's Physical Fitness Challenge) with an exaggerated wide grip, and we've continued to use this position when doing upper-body work. This choice puts more emphasis on the chest and shoulders, and while it may be fine for a couple of push-ups, Wright says that wide-grip bench presses put stress on the soft tissue of the front shoulder and can cause a tear in your rotator cuff.
The fix: When doing bench presses, Wright says, your hands should be directly over your shoulders. Tell your workout partner (you always have a spotter for these, right?) to keep an eye on your arms: Elbows should be pulled down to your ribcage and not sticking out like chicken wings.
3. The Dance Move That Can Get a Little Too DramaticThe move: Drop to one knee (a sudden fall from standing to kneeling, popular in contemporary dance fitness classes)
The risk: The cartilage around the knee is extremely pressure-sensitive, explains Wright. "If a 130-pound person comes down like dead weight directly on the knee, the pressure can permanently damage the kneecap."
The fix: Professional dancers know how to fall in a controlled way so that their knees don't even touch the ground. "If the right knee is coming down, most of the weight should be on your left quad and hamstring," says Simone De La Rue, a professional-dancer-turned-fitness-expert and creator of Body By Simone. "Use your core to keep your balance." If you don't have the core and quad strength to prevent your knee from slamming down, De La Rue says to only bend into a high lunge instead of a squat. "Create the drama by throwing your arms and head down."
Next: The ab exercise that can lead to a back injury