Understanding Reps and Sets: Your Complete Strength Training Guide
“Quality is not an act, it is a habit.” – Aristotle
Walk into any gym and you'll hear people talk about reps and sets, rest intervals, and muscle hypertrophy. For newcomers, these terms can be confusing, yet they're the foundation of effective strength training. Without understanding them, your workouts may never deliver the muscle growth, muscular strength, or fitness goals you're aiming for.
This guide explains what are reps and sets, how to structure them, and how to use them to build muscle, improve muscular endurance, and even lose weight if that's your goal.
Table of Contents
What Are Reps and Sets?
Repetitions (Reps)
A rep is a single completion of an exercise movement. For example, lowering yourself into a squat and returning to standing counts as one rep.
Your repetition maximum, or RM, is the heaviest weight lifted for a set number of reps with good form. A 12RM, for example, is the most weight you can lift 12 times before reaching fatigue.
Sets
A set is a group of repetitions performed in a row before resting. If you do 10 push-ups without stopping, that's one set. Rest, then repeat the same exercise for another 10 reps, and you've completed two sets.
Why Reps and Sets Matter
The number of reps and sets, the load you use, and the rest period between sets all determine the muscle strength, muscle size, and endurance you achieve. Even personal trainers and fitness professionals adjust these variables for each client to keep progress on track.
How Many Reps and Sets Should You Do?
Your rep ranges will vary depending on your training goal. Here's a breakdown with examples.
1. Strength and Power
Reps: 1–6
Sets: 1–8
Rest intervals: 3–5 minutes
Best for: building strength, heavy loads, and muscular strength
Example exercises: bench press, deadlifts, barbell squats
Training tip: Use higher loads and fewer repetitions to achieve maximum force output
2. Hypertrophy (Muscle Growth)
Reps: 6–12
Sets: 3–5
Rest time: 30–90 seconds
Best for: muscle hypertrophy, muscle building, and increasing muscle mass
Example exercises: dumbbell curls, leg extensions, lateral raises
Training tip: Keep tension in the muscle group and progressively increase loads each week
3. Muscular Endurance
Reps: 12+
Sets: 2–4
Rest period: 20–60 seconds
Best for: long-term muscle endurance and general fitness
Example exercises: step-ups, kettlebell swings, bodyweight squats
Training tip: Use lighter loads and short rest intervals to extend time under tension
Training to Failure and Reps in Reserve
Training to failure means you can't complete another rep with proper form.
Reps in reserve help you determine how close you are to that point. For example, if you stop with 3–4 reps left in the tank, you may not get the same muscle hypertrophy stimulus as pushing to zero RIR.
More Reps or More Weight?
If you finish a set with energy to spare:
For muscle strength, increase the weight to keep within your target rep range
For muscular endurance, increase high reps rather than the load
For muscle building, aim for progressive overload—either more reps or more weight lifted over time
Structuring Your Training Volume
To maintain or build muscle, aim for 25–45 total reps per muscle group per week, spread over 2–3 workouts.
This follows the UK Chief Medical Officers' Physical Activity Guidelines, which recommend at least two strength training sessions weekly.
Rest Intervals and Active Rest
Rest intervals are essential for recovery and muscle growth.
Strength: 2–5 minutes
Hypertrophy: 30–90 seconds
Endurance: 20–60 seconds
Between sets, you can use active rest by working a different muscle group—for example, doing free weights for biceps while your legs recover from squats.
Example Beginner Progression (12 Weeks)
Week |
Reps per Set (Repetition Maximum) |
|---|---|
1 |
15RM |
2–3 |
12RM |
4–5 |
10RM |
6–8 |
8RM |
9–12 |
5RM |
This exercise-based progression gradually shifts from lighter loads and high reps to heavy weights and fewer repetitions, maximising both muscle strength and muscle size.
Functional Benefits
Consistent strength training supports everyday fitness goals like:
Carrying shopping bags
Climbing stairs
Playing sports
Keeping up with children or grandchildren
Preventing muscle loss (sarcopenia) keeps you active and independent.
Final Thoughts
Understanding reps and sets isn't optional—it's the core of effective training. Whether your goal is building muscle, increasing muscular endurance, or losing weight, the right combination of repetitions, sets, rest time, and weight lifted will get you there faster.
If you're unsure how to create a programme, personal trainers or certified coaches such as those from the National Strength and Conditioning Association can help tailor it to your needs.