You’ll notice I come to a complete stop at the bottom of each rep. A crucial component for something called a paused squat.
Generally speaking, a 1- to 3-second pause is the goal. Although I have programmed as high as a 5- to 8-second pause, which makes medieval torture seem like a walk in the park.
You must maintain tension in the bottom, too. That’s extremely important. Don’t rely on your passive restraints—ligaments and tendons—to do the work for you.
The idea isn’t to just “hang out” in this position. You want to actively fire your core, quads, hamstrings, eyelids (basically, everything) to do the work. Not coincidentally, those who often complain of lower back pain are the ones who take the passive approach.
When you unrack the barbell, fill your belly with air. You want to achieve full expansion, which means you also push air into your back and sides.
Lock your ribcage down into place without arching your lower back, maintain total-body tension, and push your knees out to start your descent. Think about squatting between your heels. It’s okay to have a slight forward lean in your torso.
And then, pause. Most would bode well starting with a 2-second pause with each repetition, and working up to a 3 to 5-second pause.
In terms of sets, reps, and loading: I generally keep guys within 60-75 per cent of their 1-rep max for 3 to 6 sets of 4 to 6 reps. These parameters, along with fluctuating the time of the pause you use, offers a nice window of variability.