Training Guides / Training science
Sets, reps and RPE explained
What sets and reps mean, how many you need, and how to use RPE and reps in reserve to judge effort so every set is hard enough without burning you out.
A rep (repetition) is one complete movement, such as one squat down and up. A set is a group of reps done without rest, such as 8 squats. Written programs usually show sets x reps, so 3 x 8 means three sets of eight reps. Simple enough, but how hard each set should be is where most people go wrong.
Rep ranges and what they do
| Rep range | Typical load (% of one-rep max) | Main effect |
|---|---|---|
| 1 to 5 | About 85 to 100 percent | Maximum strength, skill with heavy loads |
| 6 to 12 | About 65 to 85 percent | Muscle growth and strength, the practical sweet spot |
| 12 to 30 | About 40 to 65 percent | Muscle growth if taken close to failure, muscular endurance |
Research over the last decade shows that muscle growth is similar across a wide range of loads, roughly 6 to 30 reps, as long as sets end close to failure. Strength, however, improves most with heavier loads, because lifting heavy is a skill. See hypertrophy vs strength.
How many sets?
Weekly sets per muscle group is the most useful way to count volume. A common evidence-based starting point is:
| Level | Hard sets per muscle per week |
|---|---|
| Beginner | About 6 to 10 |
| Intermediate | About 10 to 20 |
| Advanced | Individual; some benefit from more |
More is not always better. If performance drops for several sessions in a row, cut volume before you add any more.
RPE: rating of perceived exertion
In lifting, RPE is a 1 to 10 scale where 10 means you could not have done another rep. It pairs naturally with RIR, reps in reserve.
| RPE | Reps in reserve | How it feels |
|---|---|---|
| 10 | 0 | Maximum effort, no more reps possible |
| 9 | 1 | One more rep was possible |
| 8 | 2 | Two more reps possible |
| 7 | 3 | Fast, solid reps; clearly challenging |
| 6 or less | 4+ | Warm-up or technique work |
Most productive work sets land between RPE 7 and 9. Beginners tend to underestimate how many reps they have left, so it helps to take an occasional set of a safe exercise, such as a machine or dumbbell movement, to true failure to calibrate.
When to go to failure
- Isolation and machine exercises (curls, lateral raises, leg extensions): going to or near failure is relatively safe and useful.
- Big barbell lifts (squat, deadlift, bench): stay 1 to 3 reps short. Failed reps here have more risk and cause more fatigue.
- Last set only: a reasonable approach is to leave reps in reserve on early sets and push the final set harder.
Putting it together
A typical line in a program might read "Squat 3 x 5 @ RPE 8". That means three sets of five reps, with a weight that leaves about two reps in reserve on each set. If the first set feels like RPE 9, reduce the weight slightly. If it feels like RPE 6, add a little.
Write the RPE next to each set in your training log. Over time you will see your weights rise at the same RPE, which is clear proof of progress.