JUMPER'S KNEE
Tendinitis is a physical condition developed from excessive repetition of stress on a tendon. The suffix "itis" means inflammation, so tendinitis simply means tendon inflammation. Tennis elbow is a common example of tendinitis. The repeated violent arm action in tennis places stress on the tendons of the forearm and triceps muscles. Too much of this results in an overworked tendon that becomes inflamed and causes pain.
Jumper's knee is a term given to tendinitis in the quadriceps tendon, which connects the quadriceps muscle group to the front of the tibia (shin bone). The knee cap (patella) is embedded within the quadriceps tendon, so it is also referred to as the patellar tendon. Jumper's knee is commonly developed by basketball players. The sprinting, stopping, cutting, jumping, landing, cutting, and shuffling in basketball require a lot of work from the quadriceps muscles and put stress on the knee joint. With two-hour practices and games all week long, it is easy for the quadriceps tendon of an in-season basketball player to get overworked, resulting in inflammation and pain. It's important to understand that inflammation is not the actual problem. The problem is that physical stress has caused a lack of structural strength in the tendon. At a microscopic level, the tendon matrix is not properly knit together. There is typically not much visible swelling associated with what most people call tendinitis. I prefer the term tendinosis. The suffix "-osis" just means "a condition." If you have jumper's knee, your tendon is in an unhealthy condition.

Jumper's knee is a problem I ran into my sophomore year of high school. I had added 8 inches to my vertical in the preseason, meaning that all my movements now had significantly more force behind them. So looking back, it makes sense that I developed the tendinosis at that time. In my particular case, the pain flared up badly enough to sideline me for a couple of days during the season and then lasted for several months after.
I went through a process to overcome my jumper's knee, guided by an athletic trainer at my school. My first responsibility was to rest and ice as much as possible. This meant no extra work at the end of practice and taking off days completely off. I iced whenever I got a chance, especially after any activity. The method the trainer preferred for icing was to rub a block of ice directly on the tendon. I also wore a knee strap to help get me through the rest of the season. The strap can take some pressure off the tendon to prevent further injury, but it has no rehabilitative effects in itself.
In order to actually rehab the patellar tendon, I did two exercises. The first was basic body squats. The goal of these is to put a light, controlled stress on the quadriceps tendon to provide stimulus for strengthening. Correct form (knees above ankles) is critical. This exercise should not cause pain when performed. If it does, find a different rehab exercise for the time being. The second exercise I did was seated leg raises with the hip externally rotated. What the athletic trainer explained to me is that athletes, particularly basketball players, often develop more strength in the outer head of the quadriceps muscle (vastus lateralis) than the inner head (vastus medialis). This imbalance can result in the quadriceps tendon and the knee cap being pulled slightly out of line during quadriceps contraction, which expectedly results in more stress on the tendon. What the leg raises do is place the responsibility of holding up the lower leg entirely on the vastus medialis, thus strengthening it. These exercises are very easy and do not demand a lot of recovery. I used to do numerous sets of 10 each day. I just made a habit of it. I was able to limit the pain enough to make it through a few months of my season.


I was able to manage that first bout with tendinosis, but it took a long time to fix the problem. Since then I have dealt with it again and again and learned much more, so keep reading. Over time, I have come to learn that the real solution to getting rid of and preventing jumper's knee is increasing the strength and flexibility of the quadriceps muscle-tendon complex. It's amazing how many injuries and conditions are caused by a lack of flexibility. When things are tight, they undergo far more stress than if they're loose. "Stretch and Strengthen" has become my motto for curing most muscle or tendon pain. If you have even a little jumper's knee pain, make a habit of stretching the quad muscle group. Make sure to include the rectus femoris stretch. Watch the video below.

In addition to stretching, it is important to provide a strengthening stimulus to the quadriceps muscle-tendon unit. In the long term, if you can squat twice your body weight, your quads are going to be really strong, and you're most likely not going to get any tendinosis. In the case of healthy tendons, regular training is great for strengthening. Playing basketball, plyometrics, squats, and other quad exercises all place high stress on the quad tendons. The body is able to fully repair the tendons in response to that stress, so they grow stronger. Thus, it is inaccurate to say plyometrics or squats are bad for the knees. Yes, they place a high physical stress on the quad tendons, but that stress can have good results. It's when the stress exceeds the repair that tendinosis develops. This is where things get tricky. You have to learn to manage physical stress correctly. It is typically viewed as a bad thing, but stress is what causes the body to adapt and increase strength in various structures. In the case of tendinosis, you have to find the right amount of stress that will stimulate repair of the tendon more than break it down. That amount of stress depends on the current condition of the tendon. For unhealthy tendons, the same activities that strengthen healthy tendons are now the activity that cause the most pain. How are you supposed to fix your knees by increasing your squat when squatting is the thing that kills your knees? Facing this situation has forced me to come up exercises that place a beneficial stress on the quad tendons when they are not healthy.

I have a few rules for an effective jumper's knee rehab exercise.
1. Avoid deep knee flexion if it hurts. This one took me a long time to realize. You wouldn't think that a body squat could be placing too much stress on the quad tendons. Yet I've been through long stretches where I could warm up and jump 40 inches with less pain than doing a body squat. Deep knee flexion stretches the quad muscle and tendon which seems to greatly increase the stress. Thus, a body squat is actually an exercise that you will have to work up to if your condition is bad enough, embarrassing as that may be.
2. Limit eccentric muscle action. Muscles can generate the highest tension during eccentric (lengthening) contractions. In running and jumping movments, peak muscle/tendon tension occurs while force is being absorbed during the eccentric phase. Many strength training exercises like squats involve a muscle tension peak at the bottom of the movement where the weight is stopped and turned around. Modifying exercises to eliminate those moments of high tension is important.
3. Use long sets and go for a burn. I have two reasons for this. First, the stimulus needs to provoke structural rebuilding. That is done with high volume. In typical sports training, high intensity is often the goal. This promotes neural proficiency and limits increase in muscle size. But for rehab, the focus needs to be different. Growth of the damaged tissue needs to be stimulated. Second, go for a good burn in the quad muscles, because lactic acid (the substance that causes the burn) provokes the release of an enzyme that stimulates collagen synthesis in tendons.

With those guidelines in mind, I have used the following exercises successfully in my battle against jumper's knee.
Reverse Sled Drags. This exercise features minimal knee flexion and almost no eccentric muscle action because each step is small and slow. I like to do the sled drags with my feet pointed out to focus on the vastus medialis. I do 5-8 sets that are long enough to give me a really good burn in my quads. The length of the set will vary with the difficulty of moving the sled. Use 1 minute rest periods.

Box Half Squats. This is a modification to regular squats that accommodates unhealthy quad tendons. Sitting on the box eliminates the muscle tension peak at the bottom of the movement, and obviously the half squat gets rid of deep knee flexion. I do 2-3 sets of 15 or more reps.
Car Push. This is not a joke. Pushing a car provides a great structural strengthening stimulus to the quadriceps muscles. It has almost no eccentric muscle action and also allows you to control how much knee flexion is involved. I like to push my car up a hill to make it more challenging. I do 3-5 sets of 15-30 seconds. It's exhausting.
Hill Sprints. Sprinting on flat ground involves a high-speed, high-force eccentric phase. But in an uphill sprint, because each step is up to a higher elevation that phase is greatly reduced. I use a hill in a local park that takes 6-7 seconds to sprint up. I make 10 trips up the hill using the walk down as my only rest, so it's like a conditioning session. Fewer reps of a longer sprint would probably be better. Maybe 5 sprints of 15 seconds. Doing that at the end of an easier workout or on an off day has done wonders for my jumper's knee.
Stair Bounding. I live in Wisconsin, so I've had to find an indoor version of the hill sprints for the cold weather months. Stair bounding has been a satisfactory replacement. I use a 20-step flight of stairs and go up it in 5 bounds, alternating which foot I start with. I make 20 trips, again resting only to return to the bottom. Quick tip: you may find that walking down a hill or down stairs hurts your jumper's knee, because it involves the exact eccentric action in the quad muscle that you want to avoid. Walking down backward will eliminate that problem.

As stated earlier, it can be tricky to find the appropriate amount of physical stress that will promote repair in the quad tendons. It will likely require some trial and error. Use pain as your guide. This is not the case with all rehab, but with tendinosis, if an exercise hurts it's probably putting more stress on the tendon than you want. Try out some of these exercises and find a couple that allow you to get some good work in on your quads without hurting your knees. I like to do one of these exercises 3 times each week with a day of rest between. Along with that, you have to eliminate or at least limit activity that causes pain. That may mean not doing plyos or squats for a while. Lastly rest, stretching, and ice are the universal rehab tools. Connective tissue (tendons, ligaments, fascia, etc) have a low blood and nerve supply, so they recover more slowly than other body structures. This means that rehab may take a while. Of course, these things all vary depending on the person and the severity of the condition. I can tell you what I've learned, but to some extent you're going to have to figure things out for yourself.