We know you train the big guns: quads,  hamstrings, abs, lower back. But while those large muscle groups do the bulk of the work on the hill, they don’t operate alone. They need support from smaller stabilizing muscles to do their jobs right.

“If your supporting muscle groups aren’t strong, you have to change the way you ski to make up for the weakness,” says Dr. Paul Collins, an orthopedic surgeon, sports medicine specialist and avid skier based in Boise, Idaho. “Your body is amazing at doing that, but you always give up control.”

Expand your preseason workout regimen to include these secondary muscles and ligaments—inner and outer thighs, gluteus medius, calves, shins, ankles and feet—and you’ll start the season with better form, more stamina and a lower risk of injury than ever before. Here’s how.