What is it?
The knee is a hinging joint that straightens and bends with a slight amount of rotation involved. The bones are in contact with each other by cartilage, and the bones are connected by ligaments that prevent the bones from separating too far at end ranges. There are ligaments on the interior of the joint (such as the ACL and PCL) which prevent your long thigh bones from coming too far forwards or backwards onto the tibia (shin bones). There are also ligaments on the outside of the knee, the MCL and LCL (medial and lateral collateral ligaments) that connect the outside of the thigh and shin bone together. These ligaments prevent sideways motion to occur between the bones.
In snowboarding and skiing, your feet are fastened into boots that to not allow much ankle movement. This means that the forces of the hill and gravity are controlled by the next joint up, your knee. An injury to the knee ligaments when the knee becomes quickly or repeatedly brought to an end range of the ligaments. When the force exerted upon a ligament is greater than strength of the ligament itself, it becomes stretched, or torn.
What causes a ligament sprain?
During repeated or intense carving, there is a lot of strain onto the insides and outsides of the knee joints, where the MCL and LCL reside. When the force or speed of the movement exceeds the capacity of that ligament to resist it, an injury occurs. During a fall onto the knees that consists of a sudden twist, the MCL is most commonly injured. This may result in pain, global swelling to the knee, decreased strength around the joint and pain with weight bearing. More recent advancements in ski boots have reduce the incidence of ankle and shin fractures/injuries, but since that force has to go somewhere, it often affects the knees more.
How to prevent knee injuries on the slopes?
- Check your ski-boots! They should be up to date in their fitting, and have the safety release checked. Should you experience a fall on the hills, the boots should detect a change in the pressure through the boot, and release from the ski to lessen the blow to your knee.
- Try not to wear your ski boots while not in your skis for extended periods of time. This can loosen the fit of the boot, and affect the accuracy of the release mechanism.
- Ensure a proper warm-up! Stretch out your quads, hamstrings, buttock muscles prior to hitting the slopes, to that your muscles are loose and less prone to restricting movement on the hill.
- Wear a brace if you’ve experienced knee pain on the hills in the past. Braces can provide up to 30% more stability against forces acting up on the knee without one on.