Your knees are usually betrayed by repetition, not drama. A ski edge bites, the slope hardens, and each turn asks a tiring quadriceps to keep the femur and tibia tracking cleanly. Miss that line by degrees, again and again, and the ACL may face rotational load long before any spectacular crash.Fatigue is the quiet thief. As the quadriceps and gluteal muscles lose force, proprioception, the nervous...More