3. Leg Press
Why You Should Avoid It: This puts the body in a crunched, awkward, legs-in-the-air position that puts tremendous stress on the back and knees.
What You Should Do Instead: A Bulgarian split squat provides much of the same benefit in terms of lower body power with less stress on the back and knees. Place your back foot on a box or bench and then lower your hips toward the floor by squatting back and down. Without letting your back knee touch the floor, drive your weight back up with the front leg.