With feet flat beneath bar squat down and grasp bar with shoulder width or slightly wider overhand or mixed grip.
Lift bar by extending hips and knees to full extension. Pull shoulders back at top of lift if rounded. Return weights to floor by bending hips back while allowing knees to bend forward, keeping back straight and knees pointed same direction as feet. Repeat.
Throughout lift, keep hips low, shoulders high, arms and back straight. Knees should point same direction as feet throughout movement. Keep bar close to body to improve mechanical leverage. Grip strength and strength endurance often limit ability to perform multiple reps at heavy resistances. Gym chalk, wrist straps, grip work, and mixed grip can be used to enhance grip. Mixed grip indicates one hand holding with overhand grip and other hand holding with underhand grip. Lever barbell jack can be used to lift barbell from floor for easier loading and unload of weight plates.
In powerlifting, do not squat down too deep and keep shoulder joint slightly behind bar for optimal leverage and mechanics (think 'teeter toter'). Upper body will move back as weight is pulled upward. On rep training, do not merely tap weight to ground, but instead let barbell settle to ground each rep to sufficiently train range of motion through initial slack of heavy barbell. Heavy barbell deadlifts significantly engages Latissmus Dorsi.