Knee Lift Exercises While Lying Down

Performing knee exercises while lying down is an effective way to maintain range of motion and prevent muscle atrophy during rehabilitation. After an injury or surgery, your mobility may be limited, so you might be forced to exercise while lying down. Heel slides, hamstring stretches, straight leg raises and pelvic tucks can all be performed while lying on a bed or floor. Talk to a physician before you start these, or any, exercises.

Heel Slide

A heel slide is a simple exercise to promote full range of motion in the knee joint, as well as work the back thigh muscles, or hamstrings. Often recommended after major knee surgeries, this exercise is designed to be performed while lying down. Lie on your back with both legs straight in front of you. Slowly bend one knee -- most commonly the injured leg -- and press your heel into the floor or bed you're on. Keeping your heel in contact with the bed or floor, pull the heel up toward your body until you feel light tension in your knee joint. Hold the position for a few seconds before sliding your foot back down.

Straight Leg Raise

To focus on the front thigh muscles, or quadriceps, and the hip flexors -- which move your thigh toward your torso -- a straight leg raise is an effective exercise. Performed without additional weight, this movement is also often recommended after an injury or surgery. You can begin with both legs straight in front of you, or have the knee if the noninjured leg bent to no more than 30 degrees. Tighten your quadriceps muscles and slowly lift your affected leg up to 45 degrees. Return your leg to the starting position, and repeat the exercise 10 times, increasing the repetitions as you gain strength.

Knee Extension

Another exercise for your quadriceps is the knee extension. The quadriceps work to straighten the lower leg, attaching to the knee via the quadriceps tendon. Place a rolled towel or bolster under your affected leg's knee, and tighten your front thigh and lift your lower leg off the bed or floor. Hold this position for a few seconds before returning your foot to the starting position. The Palo Alto Medical Foundation recommends performing up to 20 repetitions, working your way up to three total sets.

Hamstring Stretch

Stretching your hamstrings is an important part of knee rehabilitation. Lie on your back and bend one knee toward your chest. Reach your hands forward, placing them around the back of your raised thigh, and try straightening your leg. Slowly pull your thigh closer, until you feel a stretch in the back of your leg. Hold the pose for 30 to 60 seconds, and repeat one to two times on each leg.