There is a lot of debate as to what rep schemes do what in terms of building muscle mass, muscle definition, endurance, maximal strength, etc. It is a very common belief (and you will hear this in every gym) that performing more reps creates more muscle definition. I’m unsure how this theory came about, as well as many other beliefs in regards to rep schemes.
High Reps vs Low Reps for Muscle Mass
Let’s begin with rep ranges and their uses in relation to gaining muscle mass. Before you consider any certain rep scheme, it is important to realize that the most important training principle is utilizing progressive overload. Your muscles need to be overloaded with some form of resistance in order for it to grow. One factor in achieving progressive overload is exercise volume - or the total amount of sets and reps completed during a workout, as well as general intensity. There is no single best routine or rep scheme, because there are too many other factors that come into play.
So, with that said, if you’re doing various high-rep sets to failure or past failure, you’re completing a lot more reps than if you were doing low-rep sets.
There is a much higher likelihood for muscle damage and soreness due to the extreme amount of volume. This doesn’t mean that high rep sets, however, is the best way to build muscle. If you’re able to achieve overload with extremely high intensity, lower reps, higher weight, and still keep the volume high, you may find this brings you the best results. Also take into account that not all muscle fibers are the same. You have fast-twitch and slow-twitch muscle fibers, both of which are responsible for different types of contractions and will grow based off of different workloads that designate each fiber type.
Now, let’s look at one of the most commonly discussed bro-science training principles in every gym: the assumption that higher reps increases muscle definition.
Muscle definition, just so we’re all clear, is a combination of having ample amounts of muscle in combination with LOW BODYFAT.
Do higher repetitions burn more body fat?
It’s all about how you look at it. By completing a set with higher reps, you’re going to be generally completing more volume and your heart rate will be elevated for a longer period of time during the set. This means your opportunity to burn more calories is greater, which if in a caloric deficit, can lead to weight/fat loss. BUT, seeing as how there is little to no research proving that you can spot-reduce bodyfat by training a specific muscle part, don’t exactly believe that you’re “defining” the muscles you’re working by doing higher reps.
Completing a systematic and effective diet routine which may (or may not, depending on the structure of your diet) include cardiovascular exercise is the most influential factor in creating muscle definition, seeing as how in order to make these muscles defined, you’re going to be working on reducing the body fat that is covering them.
Since the general size of the muscle will increase the likelihood of the muscle’s definition appearing through the skin, it is important to continue training the muscle as if you were trying to increase the size of it, just as you would if you were in a bulking phase. Some may choose to increase the rep ranges once they go through a cutting or dieting phase in order to get more “cut”, but since the muscle’s size is a contributing factor in the appearance of muscle definition, it is important to constantly work the muscles with a variety of exercises, rep schemes, sets, weight, etc in order to promote muscle growth. Anaerobic endurance is something that will improve when performing routines with higher rep ranges.
High Reps vs. Low Reps for Gaining Strength
It is often assumed that low repetitions will promote strength gain. This is generally true, not only due to CNS adaptations, myofibrillar volume and density adaptations, but also due to technique/forum adaptations as well. In a way, low rep schemes are also important in building mass, because if by increasing your maximal strength, you’re also increasing the weight you can use for higher-rep sets. Both high and low rep schemes are important and complement each other, so it is important to include both in your weight training routine.