Aim for the moderate rep range
The moderate rep range is king when it comes to muscle growth. The moderate rep range is from 8 to 12 reps. When thinking about how heavy you should lift, you should select weights that sufficiently challenge you. If you find yourself unable to do 8 reps, go lighter. Likewise, if you can easily do more than 12 reps, you’ll want to go heavier. You’ll know you’ve hit that sweet spot when the 12th rep is the last good rep (rep done without breaking form) you have in you.
Science supports this rep range, as seen in one popular study looking into the effects of volume on muscular adaptation in fit men. The results of the study showed that the muscle growth from doing three sets in the moderate rep range was as effective as doing seven sets in the low rep range. Besides the quantitative aspect, the group doing the low rep sets were exhausted and complained of soreness after completing their sets in 70 minutes. The moderate rep group finished their sets in 17 minutes and felt fresh and ready to do even more exercises.
Low rep range
People often associate muscle strength with muscle mass. I think this association stems from seeing guys like Ronnie Coleman easily squat 800 pounds looking like an absolute mass monster. Because of this, people often take the powerlifting approach to their training. However, training for strength and training for mass are two different things. This isn’t to say that strength training won’t lead to muscle mass gains; it just isn’t the most effective way if you want quick results.
Strength training typically involves performing exercises in a low rep range. Low rep range means 1-6 reps per set. The amount of weight you will be lifting with this rep range will be pretty close to your 1-rep max, ensuring that you won’t be able to exceed this range. While training at this rep range is still great for muscle stimulation, it’s only 50-80% effective as the optimal moderate range. This has to do with the time under tension, as low rep sets take around 15 seconds to complete compared to the 60 seconds that moderate rep sets typically need.
A study shows that research subjects performing 2-6 reps of an exercise needed 26 sets to gain as much muscle as the group that performed 8-12 reps in just half the number of sets at 13. Low rep range training will not be as efficient in building muscle, but it’s exceptional for increasing your 1-rep max.
High rep range
The common mistake most beginners make is that they just do as many reps as they can, thinking this is the most effective way to build muscle mass. While there are definitely some gains to be had with this method, the moderate rep range still proves to be the most advantageous.
The major drawback of utilizing high rep ranges is that you will fatigue more quickly, especially if you aren’t accustomed. High rep range refers to performing upwards of 12 reps per set. It can also be a major nightmare performing high reps of bigger compound movements. And lastly, the weights you will be lifting will likely not be heavy enough to recruit your fast-twitch muscles, which is where true muscle growth and size lies.
With moderate rep range optimizing hypertrophy, low rep range optimizing strength, high rep range optimizes muscular endurance. Muscular endurance is crucial for people who need a sustained level of performance, as in running a marathon or swinging a tennis racket in a long match.