Exercise Advice: Position yourself in a hack squat machine
with your back pressed firmly against the pad. Your feet should
be just beyond shoulder width apart. Begin this exercise by squatting
as though you are going to sit down in a chair. Squat to a point
to where your thighs become parallel to the floor and then return
to the start position. It is very important that you keep your back
as straight as possible throughout this movement (one way to help
do this is to focus your eyes on a spot high on the wall in front
of you throughout the entire exercise).