It depends.....but these are a great variation! 1. Set the J-hooks for the athletes typical squat height. 2. Insert the safety rods in the hole above the J-hook. 3. Put the chains over the safety pins and around the bar then clip it. 4. If using the Elitefts leader chains, clip the d-clip in the 3-5 link from the end. 5. Squat down until the bar is resting in the chain, pause, then blast your shoulders into the bar when you stand up. Athletes of similar height should share racks. Going to exact parallel isn’t needed with these. Your hips will get enough stress from this, if you are an Inch or two high, don’t worry about it. The coaching cues are the same as a box squat.
You don't need a ton of weight on these either. The athlete should use 50% of the weight they got on their Max Effort Work that week.