Both stretching and strengthening exercises are important for the treatment of jumper's knee.
Stretching the quadriceps muscles at the front of the thigh are particularly important and should be done regularly if pain allows. Eccentric strengthening exercises are usually advised, particularly for chronic more long term cases.
Testing flexibility - A good place to start is testing the flexibility of the hip flexor and quadriceps muscles. This can be tested by performing the Thomas test.
Sit on the end of a couch and pull the knee up to your chest. Holding this position, lay back onto the couch. The thigh of the free leg should be horizontal. If it rides up, this indicates possible tight hip flexor muscles (Rectus femoris or Iliopsoas). The shin of the free leg should hang vertically. If not then this may indicate tight Quadriceps muscles.
Quadriceps stretch - The quads can be stretched in either the standing or laying position. In standing you can hold onto something for balance if you need to or try holding your ear with the opposite arm. Aim to keep the knees together and pull the leg up straight not twisted. You should feel a stretch at the front of the leg which should not be painful. In the early acute stages of treatment hold stretches for around 10 seconds. Later on when the inflammation has gone stretches should be held for around 30 seconds. Repeat 3 times and stretch at least 3 times a day.
Hip flexor stretch - This exercise stretches the iliopsoas muscle and rectus remoris. Place one knee on the floor and the other foot out in front with the knee bent. Be careful to use on a mat or padding under the painful knee so at not to aggravate the injury. Push your hips forwards and keep your back upright. You should feel a stretch at the front of the hip and upper thigh. Hold for 10-30 seconds. Repeat 3 times and stretch at least 3 times a day. This exercise stretches the Rectus Femoris and Iliopsoas muscles which flex the hip. Be careful if lifting the leg up leaving only the knee on the floor. If it is painful at the knee do not do it. Ensure there is plenty of padding to avoid injuring the knee.
Strengthening exercises are a very effective part of healing patella tendinopathy or jumper's knee. But knowing which exercises to do and when to do them is essential.
Strengthening exercises should begin as soon as pain allows and be gradually progressed over a period of 6 months or more. Exercises can be separated into three phases. As a guide phase 1 lasts for the first 3 months of rehabilitation and here the aim is to increase the strength and strength endurance. Phase 2, from 3 months to 6 months can begin to increase the power and speed endurance and from 6 months onwards more sports specific rehabilitation is appropriate.
It is likely that even the more serious patella tendon injuries can begin with isometric or static contractions of the quadriceps muscles. Strengthening for the calf raises is also important and can be done without much strain on the patella tendon at all. The athlete should progress to single leg eccentric squat exercises as soon as possible. Applying ice or cold therapy after performing the exercises can help avoid any pain and inflammation.
Isometric quad contractions - this exercise is likely to be possible very early in the rehabilitation program. The athlete contracts the quadriceps muscles, holds for a few seconds and relaxes. This can be done in the standing position, seated or lying face up or face down, whatever is most comfortable although standing is probably more relevant.
Initially begin with 3 sets of 8 repetitions holding for 5 seconds and build up to 4 sets of 12 repetitions holding for 10 seconds. If it is painful during, after or the next day then reduce the load. Athletes with good quadriceps bulk should aim to progress onto single leg eccentric squats as soon as possible.
Single leg extension - the leg extension machine can be used to strengthen the quadriceps muscles if doing full weight bearing exercises is still painful. It is a step on from isometric exercises but not likely to trigger the same kind of pain that single leg drop squats may.
Begin with 3 sets of 10 repetitions with light resistance concentrating on the last few degrees of motion as the leg straightens as this is the range of motion which works the vastus medialis on the inside of the knee more. Do no more on the good leg than you are able to do on the injured leg. Gradually increase the resistance when 3 sets of 10 or 12 reps become comfortable. Progress to single leg eccentric squats as soon as pain allows.
Eccentric squats - this is probably the most important exercise to get right in the treatment of chronic patella tendinopathy. The athlete can begin with double leg squats but should pregress as soon as possible onto single leg squats.
The exercise is performed by squatting down very slowly and more quickly up. Try to use the good leg to aid the upwards movement rather than load the injured knee. The aim is to load the tendon and muscle eccentrically which happens on the downwards phase of the squat. When performing single leg eccentric squats both legs can be used during the upwards phase so the load is purely concentrated on the eccentric or downwards phase.
Eccentric squat exercises can be performed on a slant board or with a half foam roller to raise the heels. This has the effect of reducing the element that the calf muscles contribute to the exercise and increasing the load on the quadriceps muscles.
Begin with 3 x 10 repetitions each day and gradually increase to 3 x 15 repetitions before increasing the load or weight. Stick with a particular load level until they can be done very comfortably. If any pain is felt during, after or the next day then take a step back. Applying ice after can help with pain and inflammation.
Lunge - the lunge exercise should begin as soon as pain allows and is a more demanding exercise which brings increasing power and speed into the exercise. It is more likely this exercise will be introduced around 3 months into the rehab program but each athlete will be different.
The athlete stands with one leg in front of the other and bends the front knee so the thigh is horizontal while the back knee goes towards the floor. This can be made easier by not going quite so low with the front leg. Begin with 1 set of 8 repetitions building to 3 sets of 15 reps. A weights bar across the shoulders can be used to increase the load.
Step back exercise - this exercise is more suitable for the later stages of rehabilitation when the athlete is attempting to return to more specific sports training. The athlete steps back and then in one movement steps back onto the step. This is a more explosive, plyometric exercise related to the specific demands of sport. It works the calf muscle eccentrically as well as the knee during the stepping back phase and plyometrically as they push off.
Alternate so both legs are exercised and do not do any more on the good leg than you can achieve with the injured leg.