When looking to build muscle mass, what is the best rep range to do so? Should you do high reps? Low reps? Or, in between?
Before answering the question, we must first determine what is considered low or high reps, most people would consider something similar to the following when classifying rep ranges.
- 1-5 reps for Strength
- 8-12 reps for Bodybuilding
- 15+ reps for Muscular Endurance
Those guides are fairly standard and would apply to the general population, but at Real Results we don’t just rely upon general advice and we don’t believe in a one size fits all approach. We like to tailor each aspect of training and nutrition to the individual for their specific goal.
To determine what is low reps or high reps, it comes down to the individual’s muscle fibre composition. There are 2 main groups of muscle fibre; slow twitch and fast twitch. Fast twitch fibres are strong and produce power but have very poor endurance. Slow twitch fibres have great endurance but lack the strength and power qualities of the fast twitch fibres.
You are born with a proportion of both slow and fast twitch fibres but the quantity of each can differ from person to person depending on genetics. If you are born with an equal spread, then the above guides would most likely apply to you. But if you have a high amount of fast twitch or high amount of slow twitch fibres, then we would need to reconsider your rep range to build muscle.
A fast twitch fibre dominant person would possess abilities of explosive strength but their ability to repeat those efforts would be poor. If this person was completing sets of 10, 12, or 15 reps, the amount of fatigue they would experience would cause them to drastically lower the weight as they could not sustain the level of repetitions. If 8-12 reps were the sweet spot to build muscle for a mixed fibre person, then a dominant fast twitch fibre person would work in a range closer to 5-10 reps to build muscle.
On the other hand a slow twitch dominant person would not experience the same level of fatigue at 8-12 reps with the same weight because their endurance would be greater, so a better range to build muscle for a slow twitch person would be closer to 12-15 reps instead.
If both a slow twitch and a fast twitch person were doing a bench press with 80% of their 1RM (Rep Maximum), the slow twitch person would far surpass the amounts of reps that the fast twitch person could achieve. If both were to do a 1RM lift on the bench, the fast twitch individual would be able to lift a heavier weight compared to the slow twitch. This is why rep ranges can be different for people as the required stimulation To build muscle for one person may not satisfy another.
Now that we’ve addressed the differences in muscle fibre dominance and how it will dictate what is considered high or low reps for each person, we need to look at the differences between high and low reps itself. There is one key element which will always change depending on how many repetitions of an exercise you do, and that is the weight you are lifting. If you perform 5 reps of a squat compared to 15 reps of the squat, the one thing that will indefinitely change is the % of your 1RM that you’re able to lift.
This is extremely important as using a heavier load on an exercise is vital to stimulate muscle growth and to be able to develop strength. If you always lift performing high reps then the % of your 1RM will be lower, which will plateau your ability to build strength and also muscle. On the other hand always lifting low reps with heavy weight may not provide enough repetitions and stimulation for the muscles to fatigue and grow.
The best approach is to not ALWAYS lift low reps or high reps, but to go through training phases where you keep the weight the same and increase repetitions or you keep the repetitions the same and build up the weight. The body will always adapt to the stimulus you provide it and once that occurs, your ability to see results from that same stimulus becomes less and less. Be smart with your training and have a plan that will allow you to continuously progress in the gym long term.