Most pre-ski workout plans hammer the quads, hamstrings and glute max. But according to Dr. Gregory Lichtman, an orthopedic surgeon who works with the U.S. women's ski team, the muscle that really protects you on the slopes is one most people never think about: the gluteus medius, the small muscle on the outer hip.

Why does it matter so much? The glute medius stops your knee from caving inward (a position called valgus) when you load and balance on one leg — exactly what you do every time you pressure your downhill ski. When skiers drift into the back seat and the knee collapses into valgus, the tibia rotates internally, and that's where ACL tears happen. Even without a full tear, the same pattern can cause patellofemoral pain, the nagging ache at the front of the kneecap. ACL injuries are among the most common on the mountain, which is why Lichtman puts glute med strength at the centre of his injury-prevention advice.

There's a performance upside too. A strong glute med helps you form a stable pillar through your outer hip, so you can lean harder into a turn and hold your downhill ski under load instead of getting thrown down the hill by the G-forces.

The catch: unlike quads or calves, which get strong from running and climbing, the glute med rarely develops on its own. Isolation moves like side-lying leg raises work, but Lichtman prefers compound exercises that mimic sport. His pick is the monster walk: loop a resistance band above your knees, sink into a half-bend, and step sideways while keeping constant tension. Aim for five to ten steps in each direction until fatigue, rest, and do three sets. Mix in forward, backward and diagonal variations to hit different parts of the hip, and upgrade to a stronger band once it feels easy. Do this three days a week — and crucially, keep it up through the season. He flags the classic mistake of training hard pre-season, then letting dryland work slide once winter arrives. Anyone skiing two or three days a week still needs that hip and core work; only those skiing five or six days can safely skip it.

Glute strength alone won't save you, though. Lichtman stresses that strong quads, a solid core and good endurance are what keep you out of the back seat in the first place. Fatigue is a real risk factor for ACL tears — tired skiers end up in the back seat and get hurt more often. His benchmark: you should feel as fresh after lunch as you did at breakfast. So balance the weights with cardio in your pre-season routine.

For anyone booking a winter trip, this is practical homework: a resistance band costs almost nothing, the routine fits into a hotel room or living room, and a few weeks of monster walks plus endurance work could be the difference between a full week of skiing and watching from the lodge. Original reporting by Ski Magazine.