The agonist/antagonist method is training opposing muscle groups, one after the other. A set of chin-ups and then a set of chest presses. Working opposing muscle groups will not only make both stronger, you’ll burn more fat, save time, and keep your physique balanced.
Using the agonist/antagonist method of training is simple with some rudimentary knowledge of muscles and a little practice. Studies have shown that pressing strength was improved by working or even just stretching the antagonist (in this case back) muscles. Research shows that a muscle will have a stronger contraction following contraction of the antagonist muscles. So if you build your workouts in this way, you will be able to improve your strength. To put it simply; If you do some barbell rows before you do some bench presses, your chest muscles (agonist) will be less inhibited by your back muscles (antagonist) and will be stronger.
Metabolic rates of individuals training in an agonist/antagonist scheme burned up to 35% more calories during AND after the workout.
By forcing yourself to work opposing muscle groups, you will inevitably work muscle groups that you normally would not. If you want to really hit your chest from all angles, you will have to hit your back from the same angles, forcing you to target muscles outside of the standard routine.
With the agonist/antagonist method of training you will be saving time in the gym. Usually you would work one muscle group, then go right into the next without rest between exercises, otherwise known as a superset. Because you’re targeting different muscle groups, you won’t fatigue as quickly. You would only take a short rest between supersets, as each muscle group is resting while you’re working the other. If this is too intense, you can do what is called alternating sets. This method has been shown to be at least, and sometimes more, beneficial. In an alternating set, you would do biceps curls, then take a short rest before moving on to a triceps exercise.