Your knee joint is at high risk for injury, "with 5.5 million people visiting orthopedic surgeons due to knee problems each year," the American Association of Orthopedic Surgeons reports. Twisting the joint during activity can create stress and cause injury to the supporting ligaments. Ligament damage can range from mild --- with fibers suffering some micro-tears --- to severe --- a complete rupture of the ligament. Post-injury exercise can speed your return to normal activities.
Range of Motion
When you sustain damage to your ligaments, you will experience some level of pain, swelling, and decreased range of motion. The more severe the injury, the more extreme these symptoms can be.
Flexion: Sit in a chair ,with your leg resting on the floor in front of you. Slide your heel toward you, bending your knee, as far as you are comfortably able. As this becomes easier, repeat this exercise while sitting on the floor. Roll over onto your stomach, and bend your knee, with the goal of touching your heel to your buttocks. As you progress, wrap a towel or tension band around your lower leg, and pull on the ends to assist in this motion.
Extension: Sit on the floor, with your leg straight in front of you. Straighten your leg as far as you can, attempting to eliminate the space between the back of your knee and the floor. Place your hands above your knee, and apply gentle, sustained pressure. Roll over onto your stomach, and straighten your leg as far as you can, initially using the weight of your leg and gravity. As you progress, consider adding an ankle weight to increase your stretch if necessary.
Strength
Strengthening exercises can be done on a progressive level. Begin with the most basic, and increase the difficulty as you return to normal range of motion without pain.
Straight leg raises: Basic straight leg raises are typically safe to do at any point post-injury, as they place no stress on the ligaments. These can be done in all four directions.
Squats: Begin with wall squats, standing with your feet shoulder-width apart, and about a foot's length from the wall. Keeping your knees over your toes (not falling to the inside or outside), squat as far as you are able without pain, but no deeper than 90 degrees of knee flexion. As your strength increases, you may progress to unsupported squats, then single-leg quarter-squats, in which you bend your knee until it reaches a position of about 30 degrees.
Knee flexion: Lying on your stomach, bend your knee, bringing your foot toward your buttocks. Use ankle weights, tension bands, or a hamstring curl machine to boost your strength.
Knee extension: Sit with your knees flexed to 90 degrees; straighten them into a fully extended position. Again, increase resistance using ankle weights, tension bands, or a leg extension machine.
Functional Exercise
Functional exercises can assist in your return to normal range of motion, and in active strengthening. Riding a stationary bike provides both, while eliminating mishaps that may occur with regular biking. Swimming is also safe during your early recovery period. Seek medical advice on other exercises that won't stress on the ligament sooner than is healthy. Such exercises may include walking, running, hopping, jumping, and agility training.
