For some reason, recently when I do simple sit-ups, the joints in my hips pop. When doing calf raises, the joints in my ankles pop. Maybe it's wrong technique, but maybe it's a joint problem?

I know that I often wake up with my jaw locked, but I had an MRI done for TMJ and nothing was found, but the problem persists. I don't know if that has anything to do with the exercising and joints, but just in case it does I thought I should mention it.

I'm under 30, so a joint problem would be more rare, right? The joint popping with sit-ups and calf raises have only begun since july. Anyone know anything about this?

-thanks