How to Build Muscle with the Workout Principle of Rep-Max

You want to build muscle? When you train with weights in the gym, your muscles will only grow if you train hard enough. But that raises the question: how hard is hard enough?

how to build muscle

For maximum muscle growth, you need to do sets of around 6-8 repetitions (reps). The last couple of reps should be hard, but not so hard that your technique suffers (which is known in the gym as ‘bad form’). If you can do more than 8 reps of an exercise with good technique, increase the weight slightly, until you can only do 8 reps. This is called your ‘8 rep max’. Make a note of the weight that represents your 8 rep max. As you get stronger, your ‘8 rep max’ weight will steadily increase.

But f your goal is just to tone up, and build muscular endurance rather than muscle size, you should aim for 12-15 rep max (remember: rep max is the maximum number of reps you can do with a particular weight). If you can do more than 15 reps, the weight is too light, so you need to increase it until the 15th rep is really tough.

You can do combinations of weights, so that your first set is 15 rep max, 2nd set is 12 rep max, and the 3rd set is 10 rep max. Or if you’re aiming for maximum muscle growth, do a warmup set of 15 rep max, then 8 rep max, then 7 rep max, then 6 rep max.

Don’t forget, your first set of any exercise should be a warm-up set, at 15 rep max, to warm up the muscles for that specific exercise, and to rehearse the correct movement and at the correct speed (slow and steady).

The principle of rep max is closely related to the principle of ‘progressive overload’, which means that you should be pushing your limits all the time, that is if you want your muscles to get bigger over time.

Exercise alone is not enough to build muscle, you need optimum nutrition, rest and recovery between workouts,  and in particular good quality sleep.

Dominic Londesborough is a personal trainer in London with 11 years experience.