When it comes to having any type of injuries, it is important that you know exactly what is wrong. Of course, if you have knee injuries, doesn’t mean you can’t work out your upper body. Don’t just sit around doing nothing. If the injury is severe and you must get surgery, that is the first thing that you do. If you have a minor injury, making your knee have pain but can still exercise, this is how you can help yourself get better. Let’s say you have a patella problem (knee cap), it will hurt to squat, doing the leg press, or just putting pressure on it. Always work the surrounding muscles and stay very light with weight. Meaning, you can work your calf muscles, hamstrings, glutes and work on balance.
Isolating muscles surrounding the knee cap is very important, especially for injuries. Now, when it comes to leg extensions, this can be a sore subject (no pun intended). There are doctors that say don’t perform them do to the stress on the knee. But, there are a lot of people who still do it, keep the weight light, and get better. So, personally it can be preference and how your knee feels. If it always hurt especially going light, then don’t perform the extensions. The most important thing is to strengthen the muscles around the injury, by performing safe exercises. If there is pain while doing any movements, try different positions and weight.