In reality, most of the new fads like CrossFit, P90X, Insanity, etc. are simply glorified and well
marketed versions of circuit training. Circuit training is the sequential performance of exercises with
little to no rest between sets. This type of training has been around since the 1950’s and certainly isn’t
original to any of the programs that are cleverly marketing it today. To the layman, this is seen as a
quick way to get multiple training methods into one workout, and thus introduce variety. Typically,
a sequence of moderately difficult exercises is chosen at random and strung together to form a circuit.
The workout seems “hard” because at some point your performance is going to suffer due to fatigue.
This, in itself, does not comprise a legitimate method of training. Hard does not equal good. This
type of training, while not completely useless, usually boils down to some form of flopping around
for 10-30 minutes. There is no magic in this. There are also compromises that must be made if one
attempts to integrate strength, conditioning, and endurance into the same circuit (which is common).
Unfortunately – circuit training or not – if one tries to conduct strength and endurance training in the
same program, neither will be realized to their optimum potential. This has been shown in numerous
studies; attempts to combine strength and endurance training concurrently lead to diminished (or
zero) gains in both. Thus, the training is ineffective. Although these methods do induce a calorie
burning state for the first month or two, they are not designed for longevity and long term progress
(see
The Novice Effect). They inhibit it. The combination of modalities and the trend towards variety
leads to a weaker workout program.