The jump stretch bands are limiting for a few reasons.... when used in combination with other equipment - the actual band contacts the metal surfaces and sharp edges(if present)...it causes them to nick and peel apart... I know cuz two sets of mine did. Also, when you choke them up when attaching them to machines, how much resistance is it then?? Who knows?
Also... if you visit elite fts . com and see their videos on all band exercises... they have to do things differently to do traditional exercises ie., leg curls, leg extensions, back stuff, etc.
They are great... true. But limiting because of structural/design issues yes.
I would not use T.O.'s 'superman' bands through Bodylastics, or that style of bands. Those are limiting. They are too long to include with typical exercise equipment and you are 'simulating' actual gym exercises when you use them. -- Some day people are going to want to use actual gym equipment.
Jump stretch style bands are better... mine are the best... they combine both styles and can do what each of the other two can in one band system.
I use them as my core training with every exercise and muscle group. I know that 'functionaltrain' does not advocate that. I can tell you from my experience that I will never train without them.... except a week off here and there. My bench is higher than ever, my pull ups are higher than ever, and I'm putting on better size... plus I'm doing hard cardio every week. What does that tell you?... they work for power AND muscular endurance, as well as size/definition.
They work. Second.. I just demo'd my band system at a powerlifting gym yesterday... the gym liked it so much they took my only set, my prototype, and wanted to use if with their clients for everyday gym goers... bands work and are a must!!