Lately i've just been running out of energy really fast when i workout. Its mainly in my legs, i've been doing p90 workouts for a while and took a little break, then jumped back in and my legs give out really quick into the workouts. it makes it really hard to get through any of the workouts. My legs only bug me when i workout and thats it. I used to be able to breeze through the workouts.
I have a history of a bad back and i dislocated my knee cap a few years ago, i dont know if either one is relevant to the situation.
Any ideas?