Training
Reps and sets explained: what 10 reps and 3 sets of 10 mean
A rep, short for repetition, is one complete movement of an exercise, such as one squat. A set is a group of reps done back to back before you rest. So 10 reps means the movement ten times in a row, and 3 sets of 10 reps, written 3×10, means ten, rest, ten, rest, ten: thirty reps.
What a rep is, and what a set is
A rep is one complete execution of a movement; a set is a run of reps done without a rest. "Rep" is short for repetition. One squat, down and back up, is one rep. Ten squats in a row with no break is one set of ten reps. Stopping to rest ends the set, and the next run of reps is the next set.
So "10 reps" on its own means ten repetitions in a row: one set of ten. Programmes add the number of sets in front, which is where 3×10 comes from. Two related terms complete the vocabulary.
| Term | What it means | Example |
|---|---|---|
| Rep (repetition) | One complete movement, from the start position and back | One push-up |
| Set | A run of reps done continuously, ended by a rest | 10 push-ups in a row |
| Rest | The pause between sets, part of the prescription | 2 minutes before the next set |
| Rep maximum (RM) | The heaviest load you can lift a given number of times | Your 10RM is the most you can lift for exactly 10 reps |
"10 reps each side" or "each leg" means ten on the left and ten on the right, twenty movements in all. A rep counts when the movement is complete, so a half-finished final rep is not a rep.
What 3 sets of 10 reps means
3 sets of 10 reps means ten reps, a rest, ten reps, a rest, and ten reps: thirty reps with two rests between them. It is written 3×10, "three by ten" or "3 sets of 10". The rests are not optional gaps; they are what let the second and third sets be done with the same load.
The load is usually one you could lift a few more times than ten, chosen so that all three sets can be completed. Some programmes ask for the same load every set; the original 3×10, below, raised it each set.
Reading any programme's notation
The usual convention is sets × reps, so the first number is how many sets and the second is how many reps in each. It is a convention, not a standard: no governing body defines it, and training logs, coaches and apps vary. Three rules resolve almost every case.
- A number with a unit is a load. 60 kg × 10, or 10 @ 60 kg, is ten reps with 60 kg.
- A range belongs to the reps. 4×8–12 is four sets of eight to twelve reps.
- Otherwise, sets come first. 5×3 is five sets of three. If a programme writes 10×3 for an exercise that obviously is not ten sets, it has put reps first, and the author is the only authority on which.
| Written | Read it as | Total reps |
|---|---|---|
| 3×10 | 3 sets of 10 reps | 30 |
| 3×10 each side | 3 sets of 10 on the left and 10 on the right | 60 (30 per side) |
| 5×5 | 5 sets of 5 reps | 25 |
| 4×8–12 | 4 sets of 8 to 12 reps | 32–48 |
| 3×AMRAP | 3 sets of as many reps as possible | Open |
| 12/10/8/6 | 4 sets, one at each rep count (a pyramid) | 36 |
| 60 kg × 10 | One set of 10 reps with 60 kg | 10 |
| 3×10 @ 60 kg | 3 sets of 10 reps with 60 kg | 30 |
A range such as 8–12 is also an instruction for next time. The 2009 position stand of the American College of Sports Medicine (ACSM) recommended raising the load by 2–10% once you can do one or two reps more than the target (ACSM, 2009). That rule, adding load as reps come easily, is progressive overload.
Why 3 sets of 10? A 1940s army hospital
3 sets of 10 comes from a rehabilitation programme for injured soldiers, not from research comparing rep counts. In 1945, with US military hospitals overwhelmed by orthopaedic injuries, army physician Thomas DeLorme began rehabilitating patients with heavy resistance exercise built around their 10-repetition maximum, the heaviest load they could lift ten times (Todd, Shurley and Todd, 2012).
His first protocol used many more sets: 7 to 10 sets of 10, according to Physical Culture Study's reading of his 1945 paper in the Journal of Bone and Joint Surgery. By 1948 he and Arthur Watkins had cut it to three progressively heavier sets of ten (DeLorme and Watkins, 1948), reasoning that fewer repetitions allowed heavier loads. The sets ran at half, then three-quarters, then all of the 10RM (Physical Culture Study).
| Set | Reps | Load |
|---|---|---|
| 1 | 10 | Half of the 10-repetition maximum |
| 2 | 10 | Three-quarters of the 10RM |
| 3 | 10 | The full 10RM |
The programme worked markedly better than the rehabilitation it replaced and became standard in military and civilian physical therapy. DeLorme's 1951 book, Progressive Resistance Exercise: Technic and Medical Application, spread it further. The number three by ten outlived the context, and the progression in load, which was the point, is the part most people drop.
Rep ranges: what the evidence says now
The familiar chart of 1–5 reps for strength, 6–12 for muscle size and 15 or more for endurance is a convention, and the best current evidence says the size boundary in particular does not hold. The top-ranking gym guides checked on 2026-10-04, PureGym's and EōS Fitness's among them, print the chart without a source. Its authoritative version was the ACSM's 2009 position stand, which recommended an emphasis on 6–12 RM loads for hypertrophy.
Two pieces of evidence changed the picture. A 2017 meta-analysis of 21 studies compared low loads (60% of the one-rep maximum or less) with high loads (above 60%), with every set taken to momentary failure. Muscle growth was similar; gains in one-rep-maximum strength were greater with the heavy loads (Schoenfeld et al., 2017).
Then in March 2026 the ACSM replaced its 2009 stand with an overview of 137 systematic reviews covering more than 30,000 participants (Currier et al., 2026). It found that few prescription variables changed the main outcomes at all.
| Goal | 2009 position stand | 2026 position stand |
|---|---|---|
| Maximal strength | Emphasis on 1–6 RM, 3–5 min rest | Loads of at least 80% of 1RM, 2–3 sets, early in the session, 2 or more sessions a week, full range of motion |
| Muscle size | Emphasis on 6–12 RM, 1–2 min rest | At least 10 sets per muscle group per week, and eccentric overload; load is not among the variables found to matter |
| Power | Light loads moved fast, 3–5 min rest | 30–70% of 1RM, no more than about 24 reps × sets, fast lifting |
| Muscular endurance | 40–60% of 1RM, more than 15 reps, under 90 s rest | Improved by resistance training generally |
The 2026 stand also found that training to failure, set structure, time under tension and periodisation did not consistently change outcomes. In plain terms: for muscle size, how many hard sets you do in a week matters more than whether each has 6, 10 or 15 reps. For maximal strength, heavy loads still win.
This is general information drawn from reviews of healthy adults. It is not individual advice, and anyone training with an injury or a medical condition should work with a qualified coach, physiotherapist or doctor.
Rest between sets
Rest long enough to do the next set properly: around 1–2 minutes for moderate work and 3 minutes or more for heavy lifts. The 2009 ACSM stand set 3–5 minutes for heavy strength work, 1–2 minutes for muscle-building work and under 90 seconds for muscular endurance (ACSM, 2009).
The short rests long recommended for muscle growth have been tested directly. In an eight-week study, 21 trained men did 3 sets of 8–12 RM on seven exercises, three times a week, resting either 1 minute or 3 minutes. The 3-minute group gained more strength in the squat and bench press and more muscle thickness in the front of the thigh (Schoenfeld et al., 2016). Rest is part of the prescription: the same 5×5 with 30 seconds and with 3 minutes between sets are two different sessions.
Counting volume: sets per week, and total load
Volume is the amount of work done, counted either as hard sets per muscle per week or as sets × reps × load. The 2026 ACSM stand tied muscle growth to at least 10 sets per muscle group per week, which makes the weekly set count the most useful number to keep. Count every working set that trains the muscle, in every session; warm-up sets are not usually counted.
| Plan | Sets per session | Sessions per week | Sets per week |
|---|---|---|---|
| 3×10 squats | 3 | 1 | 3 |
| 3×10 squats and 3×10 lunges | 6 | 2 | 12 |
| 5×5 squats | 5 | 3 | 15 |
Total load is the other count, and it is useful for comparing sessions on one exercise. Four sets of 8 at 80 kg is 4 × 8 × 80 = 2,560 kg. Three sets of 12 at 70 kg is 3 × 12 × 70 = 2,520 kg: nearly the same work, from sessions that look quite different. Without counting, that comparison is a guess.
Keeping count without losing the set
Losing count around rep eight of twelve is the most common reason a set ends short, and the fix is to stop holding two numbers at once. Three habits do it.
- Set the rep target before the first rep. A counter with a maximum says when the set is done, so you count nothing in your head.
- Keep reps and sets in separate counters. A single number climbing to 30 does not say whether that was three tens or two fifteens.
- Write the totals down after the session. Progress is a comparison across weeks, and a counter holds the session, not the history.
Simple Online Counter is a free browser-based counter that keeps its counts in the browser's local storage, with nothing sent to a server. Its rep counter holds a rep count and a set count side by side, with a maximum per set and vibration on each tap where the phone supports it.
Frequently asked questions
What does 10 reps mean?
Ten repetitions: perform the movement ten times in a row without stopping to rest. A rep counts when the movement is completed and you are back at the start position, so one squat down and up is one rep. If a programme says 10 reps with no sets, it means one set of ten. With "each side", it means ten on the left and ten on the right.
What does 3 sets of 10 reps mean?
Do ten reps, rest, do ten more, rest, and do a final ten. That is thirty reps in three groups with two rests between them, not three. It is usually written 3×10, sets first and reps second. The rest is part of the prescription; programmes typically allow one to three minutes, more for heavy lifts.
What is the difference between a rep and a set?
A rep is one complete movement, such as one push-up. A set is a run of reps done continuously before a rest, such as ten push-ups. Reps are counted within a set and sets are counted within a session, so a session of 3 sets of 10 push-ups has 3 sets and 30 reps. The rest between sets is what separates one set from the next.
Is it sets x reps or reps x sets?
Sets first is the common English-language convention, so 3×10 means three sets of ten. It is a convention rather than a standard, and no governing body defines it. A number with a unit, such as 60 kg × 10, is a load followed by reps. A range such as 4×8–12 has the range on the reps. When a programme is ambiguous, ask its author.
Why is 3 sets of 10 so common?
Because of a rehabilitation programme. Thomas DeLorme, a US army physician, began using heavy resistance exercise for injured servicemen in 1945 and by 1948 had settled on three progressively heavier sets of 10 repetitions. Physical therapy adopted it as standard, and the number outlived its context. It was a practical clinical protocol, not the result of comparing rep counts.
How many reps should I do to build muscle?
There is no single number. A 2017 meta-analysis of 21 studies found similar muscle growth from loads at or below 60% of the one-rep maximum and from heavier loads, when every set was taken to failure. The 2026 ACSM position stand found weekly volume, at least 10 sets per muscle group, mattered more than the rep range. Heavier loads still build more maximal strength.
How long should you rest between sets?
Long enough to repeat the next set properly. The 2009 ACSM position stand recommended 3 to 5 minutes for heavy strength work, 1 to 2 minutes for muscle-building work and under 90 seconds for muscular endurance. A 2016 study of trained men found 3-minute rests produced more strength and thigh muscle growth than 1-minute rests over eight weeks.
How many sets per week does a muscle need?
The 2026 ACSM position stand associates muscle growth with at least 10 sets per muscle group per week. Count every working set that trains the muscle, across every session in the week: 3×10 squats twice a week is 6 sets for the thighs, so adding 3×10 lunges each time brings it to 12. Warm-up sets are not usually counted.
What does AMRAP mean?
As many reps as possible: one set taken until you cannot complete another rep with good form. A programme written 3×AMRAP has three such sets, and the rep count of each becomes the result you record. It is the set where an exact count matters most, because the number is the outcome rather than the target.