Place a box or bench behind you, thighs parallel to the ground when seated. Stand with feet shoulder-width apart, toes slightly out. Hold a barbell across your upper back, overhand grip, chest up, core engaged. Hips back, bend knees to lower under control towards the box. Lightly touch the box with your glutes, avoiding a sit. Drive through your heels to return to the starting position, fully extending hips and knees.
Select a box height allowing for full squat depth with good form. Maintain a neutral spine. Keep your core tight. Control the descent; tap the box gently. Engage glutes and hamstrings on the upward drive. Keep knees aligned with toes.