In the research, chains and bands are called accommodating resistance training. This is because they change the resistance your body has to overcome as you perform the exercise. Chains hang down from the barbell, as you squat down they accumulate on the floor. By accumulating on the floor they mean that you are unloading as you squat down (because the chains are on the floor). But, as you stand up the chains begin to be lifted off the floor. In other words, the more you stand up the more weight you experience.
Why would we do this? Most people are able to get out of the bottom position of the squat. However, the sticking point tends to be somewhere between the bottom position and about two thirds of the way up in the squat. Chains add weight to this important range to help strengthen your ability to overcome this sticking point.
Chains also exist in three dimensions. By this I mean that they swing slightly as you move. You have to be able to squat with this going on. This has great transfer to real life where things are not static.
Who should use chains? I think athletes need a base strength level before this is necessary, somewhere around 1.5 times bodyweight (females) and 2 times bodyweight (males). Before that there are other things that we need to be focusing on. Volume should be lower on these, sets of no more than six repetitions.
I’m at the point where I use chains as part of my warm up for both squats and deadlifts. Then when I move to my three work sets I take the chains off for those sets. This gives me the best of all worlds and to me is a lot like complex training or post-activation potentiation.
Think about it. You have to recruit more muscle fibers and more motor units to overcome and accommodate for the chains during your warm up. Then when you take them off, you are still using all those motor units and muscle fibers to perform the exercise without the chains.
If you have this equipment this can work well in a team situation, provided that your team has the base strength level to do this effectively. You would need a set of chains at each rack to be able to load the bar. You could even consider putting the chains towards the inside to reduce down time for loading and unloading weights/chains between sets.
