form on deads and box squats

[the People's Champ]

during my last workout with deads on the box squat, I realized I could lift the weight up more easy with thrusting my hips forward, instead of trying to muscle the weight with my lower back. doing so, I was able to lift more on the box. my only concern is, am I doing this correctly?

that was yesterday, and my hams are KILLING me, especially my left one where it connects to my glute...