ACL Exercises & Quadriceps Sets

Your anterior cruciate ligament, usually called the ACL, sits in the middle of your knee. During activity, your ACL prevents your shin bone from sliding in front of your thigh bone. The health of this ligament depends on proper muscular balance between the hamstrings and quadriceps. Quadriceps dominance, common among women, hyperextends yours knees and makes you more susceptible to ACL tears.

ACL Tears

• Falling backward or abrupt pivoting movements on the athletic field might tear your ACL. Knees that already have a tendency to hyperextend or lock out, are particularly vulnerable. Once your ACL tears, however, you lose your ability to bend or straighten your knee. Your doctor will probably recommend surgery, but before your operation, he will prescribe range of motion exercises such as quad sets and heel slides. These exercises continue after your surgery. Failure to perform them results in permanent loss of range of motion.

The Quadriceps Sets

• Do your quad sets before and after surgery. Sit upright in bed and extend your legs in front of you. Breathe in, then exhale, tighten your quadriceps muscles -- located in the front of your thigh -- and press the back of your knee into the bed. Do as many as possible throughout the day. When you're not exercising, keep your leg elevated to reduce inflammation, but never put anything under your knee, warns the experts at the Nicholas Institute for Sports Medicine and Athletic Trauma. Doing so keeps your leg perpetually flexed, making it impossible to reestablish extension. Instead, place a pillow under your heel.

Other Extension Exercises

• Prone leg hangs and straight leg lifts complement your leg-extension rehabilitation program. To perform the leg hang, lie face down on your bed with your legs extended and push yourself to the foot or your bed, until your knees hang off the edge. Hold the position for as long as possible while the forces of gravity work their magic and extend your legs. For the straight leg raise, lie supine with your knee brace locked. Bend your opposite knee and place your foot on the bed. Contract your quadriceps and raise your leg about 12 inches from the bed. Do as many repetitions as your physical therapist prescribes.

Heel Slides

• Your physical therapist will also prescribe knee-flexion exercises in the preoperative and rehabilitation phases of treatment. Warm up by sitting at the edge of your bed, dangling your legs and letting gravity help your knee bend. Next, lie supine on your bed with your legs extended, bend your injured leg by sliding your heel along the bed, hold for 5 seconds, then return. Do as many reps as your therapist prescribes. In the latter stages of rehabilitation, your therapist might have you sit upright, place a towel under your heel, grasp the ends and pull your heel toward you.

Wall Slides

• The wall slide, another flexion exercise, has two purposes. In addition to restoring leg flexion, it allows you to keep your legs elevated, thereby reducing inflammation around the knee joint. Put on a pair of socks and lie on your back with the foot of your injured leg against the wall and the ankle of your good leg crossed on top of it. Apply pressure with your good leg and try to bend your knee. Perform as many reps and sets as prescribed.

Progression

• As your therapy progresses, your therapist will add side-lying inner and outer-thigh exercises, stationary bicycling to increase flexion and extension, weight-bearing exercises and balance training. Although quadriceps sets are recommended for all types of ACL surgeries, the timing and type of other exercises depends on your type of surgery. Autograft surgeries take tissue from your knee, hamstring or quadriceps. Allograft surgeries use cadaver grafts. RF Escamilla researched this subject and reported that allograft surgeries require the most conservative approach. If you have a hamstring autograft, your therapist might avoid resisted knee flexion, for fear of damaging the muscles that support the harvest site.