You don't have to scrap the gym altogether. Here's how to exercise around your tendonitis injury.
Golfer's elbow, tennis elbow, swimmer's shoulder, jumper's knee. All tendonitis. Any tendon can develop tendonitis, but it most commonly pops up in the elbows, wrists, shoulders, and knees.
Your tendons bind your muscles and bones together. When it becomes inflamed, it will cause concentrated pain and tenderness. The inflammation will feel like a dull aching around a specific point when you do certain exercises. It will feel tender to the touch as well.
Tendonitis usually sources from overuse or a too-heavy, too-fast mindset. This condition presents itself in athletes who workout often, usually performing certain exercises repetitively. It can also become prevalent in athletes who do not take their rest days seriously or whose bodies have begun to age and their tendons are wearing down.
If you haven't lifted in a while and decide to pick up the weights that you used in your prime, your tendons will take on the brunt of the damage. Or, if you love to swim and keep up the hard work seven days a week, you will begin to feel a decreased range of motion and pain with each stroke.
So slow down. You do not want to re-injure or perpetuate a tendonitis injury by "powering through." You will end up having to baby it for a lot longer if you do not press pause and let the injury rest.
The pain should subside and your injury should resolve itself in a couple days or weeks if you lay off of it. Remember to ice it regularly—15 minutes on, 15 minutes off. Do not slap on a knee brace and continue your squat jumps. This will only cause the tendonitis to worsen and end up lasting months, years, or even lead to severe and permanent tendon damage.
When avoiding the inflamed area, you can get creative on ways to continue moving that don't involve the tendon. For example, if you normally go hard on the push-ups and tricep dips, lay off your elbows and sub in some extra cardio or leg work. You can continue other upper body exercises, just pay attention to any pain or tightness and nix the exercise that causes it. Add in an extra lower body day and work on your periphery muscles that you don't always work. Swimming can also be a good option (unless you have swimmer's shoulder, of course) since it is low impact and does not stress your joints.
You can also perform certain stretches in order to release the tendon from the bone and speed up your recovery. These stretches and exercises may initially cause more pain, but they will help introduce blood flow back into the area and help you heal.
If you have tendonitis in your elbow, for example, you can take a tennis or baseball and rub it up and down your forearm and elbow area until you feel the concentrated pain point. Once your find it, rub the ball as hard as you can handle (this will hurt) from side to side. The fibers in your arm run down towards your fingers. You want to rub across them, at a 90-degree angle in order to loosen them up. You may feel tingling up and down your arm—this is the blood beginning to flow back into the inflamed area. This video can help give you a better idea of what to do.