Jack finishes a focused set of exercises and re-racks the weight. His legs are wobbly, he feels light headed and he takes a big swig from his water bottle. He looks down at his watch and presses the start button to begin counting down backwards from 2 minutes.

He saw on TV that 2 minutes is the perfect rest time between sets, and what he wants is to do it exactly in that way. So, the watch beeps and he’s be back in the squat rack ready for his next set of exercises with the weights.

When thetime is up he doesn’t feel really ok. His legs still feel weak, but it doesn’t matters how he feels, because his 2 minutes have passed and he have to go back to perform another set of exercises.

So, he starts the next set. His legs are burning and he wishes that he could have had more time to prepare for this set. He starts the set, but just with a mediocre effort. He finishes the set. Again, he push the button. He does’nt know but, just as a lot of guys in another gyms, he is making a big mistake.

Working out in this way is really far from efficiency. His effort level is far less than his maximum potential. If he doesn’t change the way he trains, he will sacrifice a great ammount of muscle growth.

Muscles grow because of an adaptive response to stress. You lift X amount of weight for Y number of reps, and your body adapts to this level of stress. In order to see continual gains in muscle size, you must continually force X and Y to higher and higher levels.

In other words, building muscle is all about progression in both weight and reps. It is about lifting as much weight as you possibly can for the greatest number of reps that you possibly can (within a given rep range of course) and then continually striving to improve.

Because of this, you must always go into every single set of every single workout at your maximum strength potential. By sacrificing the amount of weight you can lift, you sacrifice the amount of muscle you can build. And there is no worse way to make this sacrifice than by not providing your body with enough rest between sets.

A watch will never tell you when you are ready to begin the next set. Instead of it, listen to your body and you will know when to follow your training.

A deadlift and a tricep pressdown aren’t exactly in the same boat here. After a heavy set of deadlifts to failure I’ll usually be resting for at least 5 minutes, often even more. A set of tricep pressdowns is obviously not as taxing and may only require a rest period of 2.5 minutes for me to feel fully recovered.