Sets and reps for strength training: what the NHS says and how goals change the numbers

Reps and sets: simple definitions

A repetition, or rep, is one complete movement of an activity, such as one lift, one push-up or one sit-up.¹ A set is a group of reps done one after the other. The NHS counts 8 to 12 repetitions of an activity as 1 set.¹

Two other words matter. Load is the weight or resistance you move. A repetition maximum (RM) is the heaviest load you can move for a given number of reps, so an 8 RM is a load you can lift 8 times but not 9. The NHS does not use the term, but the American College of Sports Medicine (ACSM) does in its position stand.⁴

If you are new to lifting, begin with how to start strength training. This page deals with the numbers: how many reps, how many sets, how long to rest and when to add more.

What the NHS and the UK Chief Medical Officers recommend

For adults aged 19 to 64, the NHS says strengthening activities should work all the major muscle groups, which are legs, hips, back, abdomen, chest, shoulders and arms, on at least 2 days a week.³ The UK Chief Medical Officers (CMOs) say the same and add that any strengthening activity is better than none.¹² Adults aged 65 and over are asked for strength, balance and flexibility activities on at least 2 days a week.¹³

The NHS then gives the rep and set figures. Try to do 8 to 12 repetitions for each activity, which counts as 1 set. Do at least 2 sets, and 3 sets give even more benefit.¹ It says to work to the point at which it would be difficult to do another repetition without help, and to start gradually and build up over a period of weeks.¹

Three limits are worth knowing. First, the NHS does not give a rest time between sets.¹ Second, it says there are no specific recommendations for how much time to spend on strength and flexibility exercises.¹ Third, the CMOs report measurable health benefits from over 30 and up to 120 minutes of muscle-strengthening per week, but say the evidence is not enough to set a recommended duration.¹²

The NHS home moves start lower than 8 to 12. The sit-to-stand is 5 repetitions, the wall press-up is 3 sets of 5 to 10, and the biceps curl is 3 sets of 5 with each arm.² Those are starting amounts, to be built up over time.²

Reps and sets by goal

The NHS figure is for general health. If you want to aim at a goal such as strength or muscle size, the NHS does not set separate ranges, so this table uses the ACSM position stand and several research reviews. They are not British sources, and we read only their published abstracts, so treat the numbers as guides and not rules.⁴⁵⁶⁹

Newer research softens the strict ranges. A review of the repetition continuum found that muscular adaptations can be obtained, and sometimes optimised, across a wide spectrum of loading zones.¹⁰ A meta-analysis of 21 studies found that heavy loads gave greater gains in maximal strength, while muscle growth was similar between low and high loads when sets were taken to failure.⁵ A larger network meta-analysis of 178 strength studies found that all prescriptions improved strength and muscle size compared with no exercise, that loads above 80% of one-repetition maximum maximised strength gains, and that the highest-ranked prescriptions for muscle size included multiple sets.⁹

Read these as research findings from healthy adults, in some studies experienced lifters, not as NHS advice. They do not tell a beginner to train to failure.

Rest between sets

The NHS gives no rest period between sets, so any figure comes from research. The ACSM abstract gives 1 to 2 minutes for muscle size and 3 to 5 minutes for heavy strength work, which is 60 to 120 seconds and 180 to 300 seconds.⁴

Two further studies point the same way, with caveats. In an 8-week study of 21 resistance-trained young men, 3-minute rests gave greater gains in strength and thigh muscle thickness than 1-minute rests.⁷ A review of six studies concluded that both short rests (60 seconds or less) and long rests may be useful for muscle growth, with a possible advantage to long rests in trained people.⁸ The 8-week study used experienced lifters, and the possible advantage of long rests came from trained participants, so do not assume the results apply to a beginner.

A practical reading for a newcomer is to rest until you feel ready to do the next set with good form. That is our suggestion, not a figure from a source.

A worked example: volume in kilograms and pounds

Some people track training volume, which is sets × reps × load. It is a bookkeeping number we use here, not one the NHS or the CMOs recommend. Suppose you do 3 sets of 10 repetitions at 20 kg:

• 3 × 10 × 20 = 600 kg of volume.
• In pounds, 20 kg is 20 × 2.20462 = 44.1 lb, and 600 kg is 1,322.8 lb.
• At the NHS minimum of 2 sets of 8 to 12 reps, one exercise is 2 × 8 = 16 to 2 × 12 = 24 repetitions. With 3 sets it is 24 to 36.¹

Research gives one more number worth knowing. A meta-analysis of 15 studies found that increasing weekly sets per muscle increased muscle gain, with each added set linked to about 0.37% greater gain. For 3 extra sets a week that averages to 3 × 0.37 = 1.11%.⁶ That is a group average slope, not a promise for any one person.

On frequency, a meta-analysis found that training each muscle group twice a week gave better muscle size results than once a week when volume was matched.¹¹ That fits with the CMO and NHS minimum of 2 days.

Examples: squat, row and press

The NHS pages we read do not give sets and reps for a squat, row or press with weights, so there is no UK figure to quote. A beginner could apply the general rule: pick a load you can lift for 8 to 12 repetitions with good form, do 2 sets, and add a third later.¹ For example, 2 sets of 10 reps of a row at 10 kg is 2 × 10 × 10 = 200 kg of volume, and 10 kg is 22.0 lb. The numbers are an illustration only.

How to log a session

A log shows whether you are building up gradually, which is the NHS advice.¹ The template below is our own; no source we read provides one. Copy it into a notebook or a spreadsheet.

Some equipment logs for you, but not all of it. The Model I app, for example, has 114 exercise videos and does not count sets, so a pen and paper work as well.¹⁴

When and how to progress

The NHS says to start gradually and build up over weeks, and to increase repetitions of each exercise over time.¹² One route, which is our suggestion, is to add reps within the 8 to 12 range, then a set, then load. Progressive overload explains this in more detail.

For the setting, see strength training at home and home gym equipment. Smaller steps in load help. Model I adjusts resistance in steps of 1 kg, which is 2.2 lb.¹⁴

The ACSM says its recommendations depend on a person's goals, physical capacity and training status.⁴ If pain or illness stops you, stop the exercise and take advice rather than pushing through.

When to speak to a GP

The NHS says to speak to your GP first if you have not exercised for some time or have medical conditions or concerns.³ The same applies to any plan with heavier loads. If you feel pain or become unwell during an exercise, stop it. If you are concerned about any symptoms, or they do not go away, the NHS says to get help from 111 online or call 111 for advice.¹⁵ In an emergency, call 999.

Frequently asked questions