I'll be demonstrating how to properly do a hamstring stretch. You want to make sure you have a shoulder width stance; you want to really lift your chest up to the ceiling and then fold at the waist. When you fold at the waist you want to make sure you maintain a neutral arch in your low back, okay? And push you weight on your heels and butt back toward the opposite wall. This is how you do a hamstring stretch. It's important when doing your hamstring stretch to not round your back unless you intentionally mean to stretch your back. This is how to not do a hamstring stretch.