I have always got a kick out of the notion of circuit training. It is supposed to be aerobic in nature, and stimulate muscle, problem is, it contradicts itself.
Cardiovascular training is aerobic, ( With oxygen).
Weight training is anaerobic, ( Without oxygen).
So what's circuit training? Kinda with oxygen?
It is an outdated concept that might only be good for the sake of variety, when you train with weights, then train anaerobically, ( get the burn). When you train cardiovascularly, then do it aerobically, ( Get a little winded). Otherwise, there is no sense trying to combine the two.
Just my two cents. E