|Utility:||Basic or Auxiliary|
From rack with barbell at upper chest height, position bar on back of shoulders. Grasp barbell to sides. Dismount bar from rack and back up until contact is made with box immediately behind. Stand with wide stance with feet flared out slightly.
Sit back onto box by bending hips back while bending knees, keeping shins nearly perpendicular or knees slightly behind ankles. Lower rear end back onto box in controlled manner. Rock torso back slightly. Once torso rocks forward, immediately stand back up rapidly by driving hips upward, keeping knees above ankles and chest high until legs are straight. Return and repeat.
Try to keep knees from traveling forward while reaching rear end back onto squat box. Ideally, knees could be behind ankles. In this position, greater stretch reflex can be created through hips (via hamstrings) once torso rocks forward just before squat. However, other hip extensors can engage in stretch-shortening cycle (although to lesser extend in this position) in lieu of hamstrings' optimized involvement.
Box Squat is said to build explosive strength by breaking eccentric/concentric chain as experienced in Barbell Squat. However, stretch-shortening cycle still occurs through altered exercise mechanics as explained above.
Adjustable safety bars on power rack should be portioned slightly below lowest position of barbell in case of fail. Box's height could allow pivot point of hips to travel slightly lower than pivot point of knee, however, programmed partials can be performed on higher box. Rubber mats can be stacked on top of box to adjust to intended height. Box can be orientated diagonally so corners can be straddled, so box is more directly under hips in standing position.
Do not fall on to or bounce off of box. Keep head facing forward, back straight and feet flat on floor. Keep knees apart so thighs point same direction as feet throughout movement. Inv olvement of Quadriceps and Soleus are limited since shin is kept nearly vertical.
During 1960s, Box squats (then called Rocking Box Squats) were first popularized by Olympic hammer thrower and power lifter George Frenn (Boyle 2010). Box Squats were later popularized by Louie Simmons. Dozens of variations are used by powerlifters and athletes using Louie Simons' Westside Barbell Program.