The aim of knee rehabilitation is to restore normal range of movement in the joint, strengthen the surrounding muscles and restore proprioception (co-ordination) of the joint.
Initially, isometric or static exercises are done, progressing to dynamic strengthing which involves movement. Finally, functional and sports specific exercises return you back to full fitness.
Introduction to knee rehabilitation & Q angle
With many sports injuries affecting the legs, one of the first muscles to waste away is the Vastus medialis muscle on the inside of the thigh. It plays an important part in the position and tracking of the patella or kneecap. The Q angle of the knee is a measurement of the angle between the quadriceps muscles and the patella tendon and provides useful information about the alignment of the knee joint.
Read more on VMO rehab and the Q angle of the knee.
Specific Knee Injury Rehabilitation
Knee Mobility Exercises
General knee mobility exercises following injury. These exercises are often done as soon as possible after injury if the pain will allow. The aim is to restore range of motion without putting any damaged tissues under stress. The exact exercises and how quickly you progress through will depend on the type and severity of the injury.
Active mobility exercises where the athlete physically attempts to move the joint through a range of motion are often the first step.
This is a knee mobility exercise to increase the range of knee flexion or bend at the joint. It is suitable for early stage rehabilitation after more severe injuries and surgery where the range of movement of the joint is limited.
The athlete lies on their back on a hard surface. The heel is slowly moved up towards the buttocks, as far as is comfortable (socks can be worn to ensure that the foot slides). After a minute or so, a further movement may be possible. A towel or strap wrapped around the ankle can be used to help in the very early stages.
Assisted knee flexion
This exercise helps to increase the range of knee flexion available at the joint. It is designed for the early stages of rehabilitation after a knee injury or surgery. The athlete uses the other leg to gently push back on the lower leg, increasing knee flexion as far as possible.
Prolonged knee flexion
This exercise is used to increase knee flexion. Sometimes after a knee or thigh injury or after surgery in this area, it is not possible to fully bend the knee. This exercise can be used in the early stages of rehabilitation to help regain full movement.
The athlete is seated, with padding on the lower leg and a strap around the lower leg, wrapped around the back of the chair and the end held in the hands. The athlete pulls the strap until a tight feeling is felt on the knee/thigh. This should not be painful. This position is held for a few minutes before attempting to increase the stretch.
Prolonged knee extension
This exercise is used to help regain full knee extension. Often after a severe knee injury or after surgery, it is not possible to fully straighten the knee. It is important to regain this full extension as soon as possible.
To help regain full knee extension, the athlete may sit with the foot rested and the knee unsupported. Gravity will help encourage extension, or weight can be placed just above the knee to add extra force. The position is held for a few minutes as long as it isn’t painful.
Early stage knee strengthening exercises
These exercises are done as soon as pain allows. In some cases, within a day or so of injury after the acute stage.
Isometric quad exercises aim to strengthen the quads by contracting the muscle, with no, or very little movement of the knee joint. The athlete can be sitting or supine depending on the degree of injury. Being seated increases the difficulty. Keeping the uninvolved knee in place, the athlete tightens the involved knee pushing it into the table.
To position the knee in partial flexion the athlete places a towel or roll under the knee. The knee is straightened (keeping the other knee flexed) and held in full extension. Hold the position for about 5 seconds and return to the starting position. This can be further progressed by raising the angle of the knee using a foam roller.
Isometric quad prone
This exercise strengthens the quads at the front of the thigh. It is for the very early stages of a knee injury or quad strain. To begin strengthening the quad muscles at the front of the thigh the athlete lies on their front with a rolled up towel under the ankle so the knee is very slightly bent. They then push down on the towel to attempt to straighten the leg and contract the quads.
Isometric hamstring exercises
Static or isometric hamstring exercises can be used in the early stages of rehabilitation for a knee injury, or a hamstring strain to help prevent muscle wasting. The athlete lies on their front with the knee slightly bent and the therapist grasps around the back of the ankle. The athlete then tries to bend their knee against the therapist’s resistance. Start with a gentle contraction and gradually increase force as pain allows. The knee should not move.
If a therapist or friend is not available, this can be achieved in a seated position. Sitting on a chair with the knee bent, push the heel back against a chair or table leg or wall.
Sit to stand exercise
This is a simple exercise that works the quadriceps in the early stages of rehabilitation after a knee injury. It is also helpful for the elderly to maintain quad strength. The athlete sits with the knees bent and feet directly under the knees. In a slow and controlled manner, the athlete moves from seated to standing and then back to seated as shown. Ensure the knees do not fall inwards.
Hip Extension on all fours
Hip extension exercises such as this work the glute muscles (buttocks) and the hamstrings at the back of the thigh. This is an early stage exercise as no weight is added, only gravity is used as resistance. In an all fours position, the athlete raises one leg behind them, keeping the knee bent and moving the sole of the foot towards the ceiling. Once at the top of the movement, they may hold the position briefly before returning slowly to the starting position.
Mid-Stage knee exercises
During the mid-stage exercises progress to gentle strengthening, gradually increasing the load on the joint and through the recovering tissues. Balance and proprioception training usually begins.
The wall squat exercise is a slightly easier alternative exercise to the squat. By using the wall some of the body weight is supported. The athlete stands with their back against a wall and the feet moved forwards. They perform a squat by sliding the back down the wall and ensuring that the knees do not move forward past the toes. The squat position can be held for added difficulty, or performed on a single leg only. A Swiss ball between the back and the wall can also be used for smooth movement.
Terminal knee extension height
This exercise increases the weight-bearing strength of the quadriceps. A resistance band is wrapped around the knee and anchored to a table leg or similar upright object. The athlete starts with the knee slightly bent and body weight on the involved leg. The knee is then straightened backward, against the resistance of the band. The knee should not be locked straight.
Standing hamstring curl
Standing single leg hamstring curl (leg curl). Start slowly then get faster as you gain in confidence. The athlete stands and flexes the involved knee. Ankle weights can be used to increase difficulty or offer resistance with the hands, or incorporate a resistance band. The athlete may use the hands-on to support the body.
Squat with band
The resistance band provides lateral or sideways resistance to add another dimension to the squat exercise. Starting with the feet shoulder width apart, the athlete squats down to no more than a right angle at the knee. The knees should not fall inwards and the back should remain straight throughout. This can be performed with a bar over the shoulders or dumbbells in the hands.
The squat is a great exercise to work most of the leg muscles, especially the quads and glutes. Stand with your feet shoulder-width apart and toes pointing straight forward. Keep the back straight as you initiate movement at your hips. Push your buttocks out behind you and bend your knees. Do not let your knees move in front of your toes or squat deeper than a 90 degree (right angle) at the knee. Start with shallow squats and increase gradually then return to the starting position.
Straight leg ball pick up
The straight leg ball pick up strengthens the hamstring muscles in a stretched position. The athlete stands with the heel of the involved leg raised. The uninvolved leg is moved back to provide balance. Ensuring that the back is kept straight the athlete bends to pick up the medicine ball. All motion involves the pelvis moving around the femurs rather than lumbar flexion.
The Plie is a wide squat exercise with the knees pointing outwards. The back should remain straight during the exercise and the pelvis should not til backward. The athlete stands with the feet turned out. The knees should be bent as if performing a squat, ensuring they do not move forward past the toes
Knee extension with a band
Knee extension exercise (or leg extension) using a resistance band to strengthen the thigh muscles. The athlete sits on the edge of the table (or on a chair) with the knees over the edge. The resistance band is placed around the ankle and anchored under the furthest table/chair leg on the side of the leg being worked on. The athlete lifts the foot upwards to straighten the knee, then returns to the starting position. If the pain is felt do not continue with this exercise.
Seated hamstring curl
Seated or supine hamstring curl exercise using a resistance band. The athlete sits with a resistance band around the ankle with both legs straight. A partner holds the band in both hands until it is taut. The partner must not move the band from the starting position. The athlete draws the ankle in towards the buttocks increasing the resistance of the band, then returns to the starting position
This exercise works the hamstring muscles and can be progressed to use weights depending on the state of the injury. Lying on their front with the foot pointing down over the edge of the couch, the athlete fully bends the knee. Provided this is pain-free, a resistance band or ankle weight can be used to increase difficulty.
Single leg catch exercises for hamstrings. This starts to strengthen the hamstrings eccentrically or as they lengthen. In a prone position, the athlete lifts both legs to a 90-degree angle. Ensuring that the leg and the foot are not turned outwards the athlete drops the leg attempting to stop or ‘catch’ the lower leg reaching full extension. Alternate the legs.
The athlete can increase the difficulty of this exercise either by adding ankle weights or speeding up the rate of the leg catch.
Advanced knee exercises
Late stage or advanced knee exercises are more functional and sports specific. The aim is to restore full strength and mobility to the joint and return the athlete to full training and competition.
Lunge with ball
A ball can be used with a lunge to help with balance and to add extra weight. The athlete stands with the injured leg a wide stance in front of the other. The athlete holds a medicine ball close to the chest With the weight shifted onto the front leg, the back knee is slowly bent and dropped down towards the floor. This exercise works the Glutes, Quads, and Hamstrings.
Lunge on step
By raising the uninvolved leg on a step the athlete adds more weight to the leg being worked on. The athlete stands with the injured leg a wide stance in front of the other. The uninvolved leg is raised on a step with weight on the toes. With the weight shifted onto the front leg, the back knee is slowly bent and dropped down towards the floor.
This exercise is ideal for not only strengthening the muscles of the lower extremity but also for burning calories! The athlete stands with the injured leg a wide stance in front of the other. With the weight shifted onto the front leg, the back knee is slowly bent and dropped down towards the floor. The lunge position may be held to increase difficulty. Walking lunges are a more advanced version of the lunge.
By using a medicine ball in the lateral lunge (side lunge) the athlete is able to add weight to the exercise as well as using it to aid balance. The athlete steps to the side keeping the toes forwards and the feet flat. Whilst keeping the involved leg straight, squat through the hip of the involved leg ensuring that the knee is in line with the foot. The athlete holds the ball out to help maintain balance. Squat as low as possible and hold for 2 seconds. Push back to the starting position.
Eccentric squat knee exercises target the hamstrings, glutes, and quads. The athlete raises the heels using half a foam roller. Keeping the back straight the athlete lowers themselves down slowly. The athlete returns to the starting position then repeats. To increase the level of difficulty the athlete can lower the body closer to heels. This exercise can also be executed on one leg.
Norwegian hamstring curl
The Norwegian hamstring curl (or Nordic curl) requires either a partner or gym equipment to lock the lower legs securely. This is a very advanced exercise isolating hamstring muscles. A partner anchors the athlete’s calves. A straight line must be maintained from knee to shoulder.
The athlete lowers the body as controlled as possible to the floor. At the point whereby the move becomes uncomfortable, the athlete lets the body fall to the floor using the hands to control their landing. As the hamstrings get stronger less upper body push can be used the athlete can raise themselves back to the start position.