30-25-20-15-10 and 5 rep rounds of:
A Burpee is a movement that starts from standing, then drop down to place both hands on the ground. From there, kick the feet out behind you. Do a push up. Bring the feet back in toward your hands, stand up and jump into the air with your hands above your head. This is one ‘rep’.
Rounding of the back especially when bringing the feet back in and standing up and sagging of the back during the push up might cause back problems especially in the higher rep ranges. Try to prevent this by keeping the back straight through the entire movement.
An “L Pull-up” is a pull up with your legs pointing straight out in front parallel to the floor. If you can’t do any of these, try doing regular pull ups interspersed with just hanging on the bar with your legs out in front.