Guide to Sets, Reps, and Rest Time in Strength Training

Sets, repetitions, and rest intervals are the basis of weight training programs. You need to know what they mean and how to mix and match them for best effect to reach your goals.

Your training program will differ in the weights used, number of repetitions and sets, rest intervals, and speed of execution depending on whether you are training for fitness, muscle growth, strength, power, or endurance.

Reps, Sets, Rest, and Speed

The first step is understanding these terms and how they apply to your workout program. In brief, a rep means repetition, and references one complete movement. So, one bicep curl equals one rep, and 5 bicep curls are 5 reps. Reps make up a set, which is usually the total number of reps you'll do before taking a break. You'll find more detail on sets, reps, rest, and speed below.

Reps

A repetition (rep) is one completion of an exercise, such as one deadlift, one bench press, or one arm curl. A repetition maximum (1RM) is your personal best, or the most you can lift once in a single repetition of an exercise. Therefore, a 12RM is the most you can lift and successfully perform 12 repetitions with proper form.

Sets

A set is a series of repetitions performed sequentially. For example, eight repetitions can be one set of bench presses.

Rest

The rest interval is the time spent resting between sets that allow the muscle to recover. The rest period between sets may range from 30 seconds to two minutes. Some exercises also have short rests between reps.

The ideal rest period depend on your goals. Muscle hypertrophy, or muscle building and growth, may require less rest than power lifting, for example.

• Muscle hypertrophy: 30 to 60 seconds
• Muscle endurance: 30 to 60 seconds
• Power: 1 to 2 minutes
• Strength: 2 to 5 minutes

It's important to time your rest between sets. If you don't rest long enough and start with another set too soon, you may fatigue your muscles too quickly and risk injury. If you rest too long between reps, your muscles may begin cooling down and releasing tension before you start again.

Speed of Exercise Execution

Contraction velocity is the speed at which one rep of an exercise is performed. This has an effect on training goals and results. Both concentric (shortening of the muscle; often the lifting part of a rep) and eccentric (lengthening of the muscle, often the lowering part) moves help to build muscle mass.

• Strength: 1 to 2 seconds concentric and eccentric
• Hypertrophy: 2 to 5 seconds concentric and eccentric
• Endurance: 1 to 2 seconds concentric and eccentric
• Power: Less than 1 second concentric, 1 to 2 seconds eccentric

How to Choose Weights

The theoretical distribution of repetitions against a percentage of 1RM (your maximum lift) is as follows. This example uses a bench press where your 1RM is 160 pounds.

• 100% of 1RM: 160 pounds, 1 repetition
• 85% of 1RM: 136 pounds, 6 repetitions
• 67% of 1RM: 107 pounds, 12 repetitions
• 65% of 1RM: 104 pounds, 15 repetitions
• 60% of 1RM: 96 pounds, warm-up reps

You should be able to do one lift at your personal best, six lifts at 85% of your personal best, and 15 lifts at 65% of your 1RM personal best. This is a guide you can refer to when you choose appropriate weights for working out.

Use Goals to Build a Program

A training program is a schedule of exercise types, frequency, intensity, and volume, whether for weight training or any other fitness training. You can devise many combinations of sets, reps, rest, and exercise types to find what works best for you. A qualified strength and conditioning trainer can help you plan a program.

These variables can be adjusted in any weight training program:

• Exercise selection
• Weight or resistance
• Number of repetitions
• Number of sets
• Velocity of movement
• Rest time between sets
• Rest time between sessions (training days/week)
• Time between periodization cycles

Training for General Fitness

A basic strength training fitness program should target both strength and muscle-building. Between eight and 15 repetitions for two to four sets will help you accomplish both.

Choose eight to 12 exercises, making sure to hit your lower and upper body and your core. At this stage, don't lift too heavy or too light (you should feel fatigued by the last rep, but it shouldn't be overly difficult) to ensure a good foundation before trying more goal-specific workouts.

Training for Strength

To build strength, use the most weight, the least number of repetitions, and the longest rest periods. When your aim is strength, lift heavier for fewer reps, compared to when you're trying to build muscle size or muscular endurance. The neuromuscular system responds to heavy weights by increasing your ability to lift those heavy loads.

For example, those with a strength goal might use a 5x5 system. That means five sets of five repetitions. You'll use relatively higher loads (heavier weights), plus take a longer rest between sets (about three to five minutes).

Training for Muscle Growth

Hypertrophy for muscle size and bodybuilding training uses lighter weights, more repetitions and less rest time. Muscle requires metabolic stress to increase in size. This means working the muscle to the point where lactate builds and muscle suffers internal damage, then resting and eating appropriately to help the muscle repair. The muscle grows larger in the process.

This sort of training requires a higher number of repetitions in each set in order to stimulate that breaking point. It is sometimes called "training to failure."

A typical approach to reps and sets for those looking to build muscle might be three sets of eight to 12 reps, at loads that reach failure point (or near) on the last few repetitions.

Training for Power

Power training involves somewhat lighter weights and longer rests while concentrating on the speed of execution. "Power" is the ability to move an object at a high speed. Power training requires practicing the acceleration part of a lift, then resting and repeating.

In power training, you lift moderately heavy weights, accentuate the concentric first movement of the exercise, then rest sufficiently to recover before doing that rep or set again. You need to ensure each push, pull, squat, or lunge is done at a quick tempo.

Training for Muscular Endurance

Endurance weight training requires more repetitions in each set, perhaps up to 20 or 30, with lighter weights. You may want to consider why you set this as your goal. What is the day-to-day function that requires muscular endurance? For example, if you're a runner, you might want to concentrate on endurance in your legs. Swimmers might focus on their arms. 

Training for Olympic Lifts

Olympic lifting requires strength and power. Olympic lifters train to do just two lifts: the clean and jerk and the snatch. Training sessions include six or fewer repetitions for a higher number of sets, about 10 to 12. The goal here would be to get better and stronger at these particular movements, and also increase the weight used in the exercises.