The 3 Things That Actually Cause Muscle Growth

Building muscle is no easy task. Especially if you don’t even know what builds muscle in the first place.

Sure, we know we should engage in some kind of resistance training and eat more to support muscle growth, but what about the reps and sets that we choose to use actually cause muscle to grow?

The age old question of heavy weights and low reps vs. lighter weights and high reps always seems to confuse people. The answer isn’t one or the other, but BOTH.

Muscle growth is caused by 3 different factors:

Mechanical tension

This is in relation to the actual weight lifted. The weight must be HEAVY enough to stimulate a change. However, the greater the mechanical tension, the less volume you can build up. For example, a powerlifter squatting 700 pounds for 1 rep is a lot of mechanical tension but not enough volume to cause significant muscle growth. On the other hand, the ladies at the local fitness center doing 100 rep bicep curls with the 5’s is a ton of volume but not enough mechanical tension to stimulate the gains.

Muscle damage

When lifting weights the amount of volume (sets x reps) is related to the amount of muscle damage you’re trying to produce. More muscle damage sets the stage for more muscle to be built back up when it’s time to repair itself. The trick is to find a happy medium for volume because there can be too much volume or not enough.

Metabolic Stress AKA the PUMP

The pump is the swelling that you feel during a training session and is usually caused by higher rep training. It’s actually not the muscle but a bunch of non-contractile factors like blood and fluid. This swelling can be perceived as a threat to the muscle cell’s structural integrity and thus it will build itself up to withstand these forces over time.

So what’s a person to do? What set and rep range should you train in to start building some muscle?

All of them.

Here’s what a workout would look like if you were going with a traditional body part split focusing on back:

1. Deadlift 5×5
2. Chin Up 4×6-8
3. DB row 4×8-10
4. Lat pulldown 4×10-12
5. Rear delt flys 3×15

The Best Approach

The best approach to training for muscle growth would be a blend of heavy weights with lower reps (3-5 reps), moderate weights in a moderate rep range (6-12 reps), along with higher rep sets to really push the pump (15-20+).

Chances are you’re already training in at least one of these rep ranges so try adding some training in one of the others. By stimulating all of these factors you can stimulate the most muscle growth and leave no stone unturned.