The pain you're experiencing along the back of the knee while cycling is likely the result of something known as biceps tendinosis. Also referred to as biceps femoris tendinopathy, it's often marked by an inflammation of the tendon that connects the muscles of the hamstring to the outside of the tibia. Cycling requires a repetitive movement of the knee, which can cause you to overuse or overstretch this tendon, eventually leading to injury and pain.
The most common symptom of this condition is posterior knee pain. Typically, this pain is at its worst when the knee is bent and pressing down into the pedal stroke. You may also notice that your hamstring is overly tight as you peddle, and that there is some leg stiffness after cycling.
For some people, resting the legs can help to lessen the inflammation of the tendon and alleviate the posterior knee pain. Icing the back of the knee may also prove to be beneficial. Like rest, icing the area can lessen the inflammation and relive the pain. However, only administer cold therapy for 15-minute intervals, as any longer could exacerbate your injury.
If rest and cold therapy fail to improve your posterior knee pain, you may need rehabilitation. Talk to a doctor or physical therapist to determine the best course of treatment. Though therapy is typically based on the individual, it usually entails exercises to stretch and strengthen the hamstring. Stretching improves flexibility, while strengthening can prevent the injury from recurring.
To stretch the hamstring, sit on the floor with your legs fully extended in front of you. Lean forward, bending at the hips, and reach your hands toward your feet. Hold this position for 30 seconds and release. Do this stretch at least five times throughout the day.
To strengthen the hamstring, stand near a wall or door frame for balance. Bring your feet and knees together before slowly kicking your foot back off the ground. As you lift your foot away from the floor, keep your knees together. Complete three sets of 10 reps.
Preventing this type of injury is sometimes as easy as adjusting the position of your saddle. If you're seat is too high or too far back, you're forcing your leg to stretch farther than necessary. As you peddle, you're placing undue stress on the posterior region of your knee, thereby overstretching the tendon. Besides the saddle of your bike, the cleats of your shoes can also contribute to this pain. If your shoes cause an internal rotation of the foot, you stress and subsequently overstretch the tendon.