I have been doing Body weight exercises and while when I am doing squats my legs get fatigued and sore by the time I get to 40 or 50, however the next day my legs are not sore at all. I am wondering if I am working them hard enough my guess is no. However if I do squats everyday by the 4th or 5th day the number of reps I am able to do plummets and I thought about using dumbbells to add resistance but I can't get through 50 without muscle fatigue now. I am not understanding how I can do squats till I can barely walk down stairs and the next day it's feels like I didn't workout at all. Any help or explanations or suggestions I would greatly appreciate.