Ninety-nine out of a 100 lifters do multiple sets of a particular exercise in succession, or straight sets. For instance, they'll do one set of bench press, followed by another set of bench press, followed by another set of bench press. In between sets, they'll "recuperate" while pretending to pull a loose thread on their socks while scouring the playlist on their phone.

Research tells us they would have much better recuperation by performing a set for an antagonistic body part in between sets.

It works like this: Do a set of dumbbell bench presses, do a set of barbell rows for your lats in between, and then go back to your next set of dumbbell bench presses. (Then keep alternating for the desired number of sets.) You'll actually experience less of a drop in strength from set to set compared to straight sets.

No one is sure why, but it surely has to do with the neurological system. This is why I began using the "A1" and "A2" designations on my workouts, a method that has since been almost universally adopted by trainers. Unfortunately, the trainers who use it don't understand why they use it, or, if they do understand it, rarely explain it to their athletes.

Other examples of appropriate antagonistic body part pairings:

• Biceps curl and triceps extension
• Leg extension and leg curl
• Overhead press and pull-up