Like all things health and fitness, rep ranges (the number of consecutive repetitions of an exercise you perform before resting [or moving on to the next exercise]) can be as complicated as you allow them to be. From utilizing different energy systems to activating different types of muscle fibers to controlling Time Under Tension, there are as many ways to manipulate rep ranges as there are opinions on which way is best.
But who has the time?
In the context of general health, strength, and fat loss goals, there is no need to analyze different rep schemes for their effect on the cellular level. It is important, though, to have a simple understanding of the benefits of different rep ranges, especially when putting together your own workouts.
A Quick Note
The number of reps performed in a given set does not stand alone: it is related to the weight being utilized. To put it another way, you cannot take the same weight and simply decide how many times you’re going to perform an exercise in order to garner different effects. The weight must change with the rep range, with the goal typically being to reach or approach failure by the final rep.
Did that seem wordy? It felt wordy…
I’ll give you an example. Say you’re doing single-arm dumbbell rows. You would not take a 25-pound dumbbell and then decide whether to perform a high-, medium-, or low-rep set; rather, you would decide which rep range you wanted to utilize, and then choose a weight accordingly. Perhaps the 25-pound dumbbell for high reps, the 35 for medium reps, or the 50 for low reps.
The Different Rep Ranges
In generally-accepted terms, we discuss repetitions in three ranges: low, medium, and high.
The Low Rep range is typically between 1 and 5 repetitions per set. Because of how this range (and corresponding weight) stimulates the body, its main function is strength gain. In relative terms, this range uses very heavy weights (remember, reaching or approaching failure by the final rep).
A Medium Rep range would be anywhere from 8 to 12 reps per set. The main purpose here is typically to build muscle, but don’t let that fool you into thinking you will automatically look like a bodybuilder if you use this range. Likewise, don’t think that working in this range is all it takes to pack on large amounts of muscle. It’s not.
This range usually makes use of moderately heavy weights, if you can believe it.
High Reps would be from 15 to 20. (Some people might call this category 15+, but I think I might categorize 97 reps differently than I would 15...) This range is especially useful for building endurance, which is to say you can exercise longer before reaching failure.
Though this range uses the lightest weights of the three categories, it's important to keep in mind that we're talking about relatively light weights. A weight can seem light at the beginning and quickly feel like an anvil, but if your light seems weight throughout the entire set, you might want to kick it up a notch.
Which One Should I Choose?
The short answer is...all of them! Just not at the same time.
None of these rep ranges or associated goals operates in a vacuum. Each one has a place in your workout routine, and they can all work synergistically to help you achieve your goals. If you build up your strength, for example, you may be able to add more weight when exercising for hypertrophy. More endurance would mean you might perform more total volume throughout your workout.
When creating your own workouts, try to think in terms of cycling rep ranges rather than changing them every time. It can be counterproductive to give your body constantly changing signals (“Get bigger. No, get stronger. Quick - last longer!”), so try sticking with a particular rep range for a few weeks, and then change things up once you’ve given your body time to adapt.