Use a bench/box that is approx knee height. Start in a lunge stance with your back foot elevated and your front leg about half a metre in front of you. Set your shoulders back and down, back straight, abs pulled in. Send your hips back and down, and lower your back knee until it nearly touches the floor keeping your glutes engaged the whole time. Drive through the front heel to stand tall and squeeze your glutes at the top.

Quads

Lunge