The knee is the most complicated joint and endures many stresses, making it especially vulnerable to injury. The anterior cruciate ligament (ACL) can be injured in many sports, because it can tear from abrupt changes in motion, landing a jump, or running then suddenly stopping. The medial collateral ligament (MCL) on the inside of the knee is often injured from a blow to the outside of the knee, which overstretches the MCL and may tear it. A cartilage injury can occur when the meniscus — the cartilage that acts as a shock absorber for the knee joint — tears from motions such as twisting, slowing down or from a direct hit.
Many people also suffer from chronic knee pain due to osteoarthritis, pes anserine or prepatellar bursitis, rheumatoid arthritis, chondromalacia patella, tendonitis, and many other conditions. However, it is still possible to exercise with knee problems as long as the exercise is low-impact. In fact, exercise can be crucial to recovery as it helps to strengthen the joint, which may also prevent future injuries.
Swimming is one of the best exercises for people with knee pain, because it does not put much stress on the joints. Walking is another good low-impact exercise that can be very beneficial for weight loss as well. It’s best to start slowly and work up to 20 to 30 minutes at a moderate pace. If possible, walk on dirt paths or grass instead of concrete for better cushioning.
The gym can seem like an intimidating place for those with bad knees, but there are many options for working out. Elliptical machines and recumbent stationary bikes are the best machines for low-impact exercise. Treadmills are also a good choice, set at a low incline and intensity. Begin exercising after a five to ten minute warm-up and leg stretches. While exercising, avoid bending the knee past a 90 degree angle.
Strengthening the quadriceps (front thigh muscles) and hamstrings (back of the thigh) will help stabilize the knee. To work the quadriceps, try straight leg raises, wall-supported partial squats (lean against a wall or use a Swiss ball to roll down), and isometric exercises. For the hamstrings, try hip raises or straight leg deadlifts. People with painful or weak knees should not do full squats, lunges, or high-impact activities such as soccer, running, or kickboxing.