I have a question regarding quadriceps tendonitis.
I am 21yo male (155lbs/70 kg, 6ft/183cm) and I've been doing bodyweight exercises for approximately six months now. Started by doing this program and the ones connected to it and then I slightly adapted them to my needs and liking as I progressed: http://www.twohundredsquats.com/ I have just recently joined reddit and subscribed here, so I am still catching up, but I don't want to wait until next Monday with this question because I want to do squats :)
I have had rheumatoid arthritis in my knees since I was 6 years old, but I haven't had any serious symptoms in the last 10 years or so, except for knee pain after prolonged sitting, especially when I am not active for a few days. I solved this problem by walking to work and taking regular breaks from my desk job throughout the day.
However, I have recently had problems with quad tendonitis on several occassions. I was doing squats and lunges according to the programs above and, as soon as I got to very high reps (200+ squats and 100+ lunges total) I would have pain for a few days if I didn't stop doing them. It would hurt during everyday activities (climbing stairs, sitting up and down...) as well as when exercising. I thought it was because of poor form and I would try again after a few weeks, but the pain returned. I dropped all leg exercises because of this, but I definitely do not want this to be the long-term solution.
In the last few weeks I haven't been doing either squats or lunges and I have felt pain in the tendons again. It's not as intense as before, but it's certainly there. I should probably mention that my tendons also hurt when I ride a bycicle, as soon as I up the intensity (no matter how long I ride).
So at this point I am not sure whether it was the exercises or something else. I have read different articles on the topic, but I would rather hear from people who have experienced (and solved) the problem themselves.
Could the reason be my faulty knees, poor form, lack of mobility/poor stretching or something else?
Thanks in advance