Stand upright with the barbell centered over your feet. Keep your feet hip width apart and your toes slightly pointed out. Hinge at your hips and use an overhand grip to grasp the bar at shoulder width so that your shoulder blades can elongate.
Lower your hips and bend your knees until your shins come into contact with the bar. Look forward while keeping your chest up and your back arched. Drive through your heels to lift the weight upward.
After the bar passes your knees, pull it back as you straighten your back by raising your chest. You should be pulling your shoulder blades together as you drive your hips forward into the bar. Make sure that you lock your hips and knees, move your booty back, and fire your glutes as you stand up with the bar (this movement comes from your hips, not your knees).
Unlock your hips and knees so that you can lower the bar by hinging your hips back down. Bend your knees after the bar passes them and use your hips to guide the bar to the ground. The bar should land centered over your feet at the starting position.
Find a squat rack and set the height of the bar slightly beneath your shoulders. Stand with your feet at about hip width apart. Step up to the bar, move under it, and grip it with an overhand grip. The barbell should be supported on top of your traps.
Your chest should be up and your head facing forward. Once the bar is on your back, stand up, flex your core, tighten your glutes, and step away from the rack.
Begin squatting by lowering yourself until your legs reach a 90° angle and your thighs are parallel to the ground. Your knees will move forward, but ensure that they stay aligned with your feet.
While keeping your torso upright, drive your heels into the ground to push yourself back up.
Sit on the machine with your back against the pad. Adjust the leg pad so it rests against your ankles.
Secure the lap pad against your thighs, right above your knees. Grasp the handles on the machine to assist you in pointing your toes straight (flexing your feet).
Grasp the handles for support and flex your knees as you curl the weight back as far as possible toward the back of your thighs. Keep your torso stationary at all times and squeeze your hamstrings once you have moved the weight as far back as you can.
After a second, slowly return the weight to the starting position.