Sets and Reps

Everything You Need to Know About Sets and Reps

Sets and RepsWhy Are Sets and Reps Important?

Sets and repetitions are fundamental weight training concepts to understand thoroughly. When you perform a specific exercise, you typically repeat a specific action a certain number of times, or reps. Reps is short for repetitions. The number of repetitions you perform before you stop is a set.

Understanding sets and reps is important because everything you do during a workout is organized into sets and repetitions.

Phases of Each Repetition

There are three phases of each repetition. During each rep, it is very, very important to focus on all three phases in order to get a complete set and an optimal workout.

Concentric Phase

The concentric part of a rep is the muscle-shortening phase. You can think of the concentric phase as the part of a lift when you raise the weight against gravity. You usually exhale your breath as you complete the concentric phase.

Many weight lifters focus solely on the concentric phase. This is a HUGE mistake, because your muscles respond better to training when you focus on all phases of each rep. Don’t waste your time by only focusing on the concentric phase. You’ll get more out of your workouts by dividing your focus between each of the three phases.

Eccentric Phase

The eccentric part of a rep is the muscle-lengthening phase. You can think of the eccentric phase as the part of a lift when you lower the weight under control, resisting gravity so that the weight doesn’t drop too fast. Most of the time you exhale your breath during the eccentric phase.

This is the most neglected part of the rep. Your muscles can handle a heavier load during the eccentric phase, which makes it important to always lower the weight slowly under control.

There is even an advanced technique called “eccentric negatives”. Negatives involve using a weight which is heavier than you can lift concentrically. This helps build muscular strength so you can lift heavier and heavier loads as you continue your training.

Isometric Phase

The isometric portion of a rep is when the muscle is neither shortening or lengthening, but is still under tension. The muscle is busily contracting, but remaining the same length. You will hold your breath for a beat during the short isometric phase.

You can think of the isometric phase as the action of your muscles when you push against a brick wall. Your muscles are working like crazy, but neither your muscles nor the brick wall are moving.

The isometric part of the rep is often neglected. It is important to pause for at least a split second after each eccentric (lowering) phase. It is essential to be able to stabilize any weight isometrically before heavier loads can be used.

Isometric-only training was used before weight lifting became mainstream. Believe it or not, isometric-only training is very effective for building muscle.

The main disadvantage of isometric training is that your muscles are not brought through their full range of motion. Therefore, only the range of motion in which you’re exercising is strengthened during a static rep.

A wall sit, in which you sit against a wall with your legs at a 90 degree angle is a good example of an isometric exercise.

The leg muscles only are strengthened in that angle. Thus, it’s a good idea to perform complete sets and reps using all 3 phases of the lift for your legs as well as your whole body.

Several Exercise Factors Determine How Many Sets & Repetitions to Perform

Quality should always be more important that quantity for each set and rep of each exercise. This holds true regardless of the exercise or the phase of training. The only exception to this rule is if your specific goal deals with a quantity. If you want to do 1000 push-ups, you will have to train sacrificing form some of the time. You will be better off health- and fitness-wise if you set goals which support quality over quantity, though.

Exercise Form

Weight training is not a counting exercise. There is no magic number when it comes to sets and reps. It is most important to perform a quality set of quality reps than 10, 15, or 20 reps. Since the quality of sets and reps is most important, rep quality determines how many sets and reps you perform. If you are unable to keep up proper form for an exercise for each rep of your set, you should stop.


Failure is when you try to complete another repetition with perfect form, but your muscles are completely fatigued. A perfect set is one in which you complete just under the desired number of repetitions. If you pick up a certain weight with the intention of completing 10 repetitions and can only complete 9.5 with perfect form, you have succeeded by reaching failure.

If you reach failure during the first set, some experts claim that you do not need to perform another set. This is debatable, but you can try and see what works best for you.

Rest in Between Sets

The amount of time you take to rest in between sets has a direct correlation to your ability to perform the next set. Weight training is an anaerobic exercise, so full recovery in between sets is around a minute.

Muscles Being Trained

Your body’s muscles are composed of two different types of muscle fibers: slow-twitch and fast-twitch. Your genetics and training can effect the ratio of type I to type II muscle fibers in your body.

  • Slow-twitch muscle fibers (type I)
    • Built for endurance and highly resistant to fatigue. Muscles composed of primarily slow-twitch fibers, such as the abdominals, respond better to higher repetitions.
  • Fast twitch muscle fibers (type II)
    • Built for strength and power, thus less resistant to fatigue. Fast-twitch muscle fibers respond better to a low or moderate range of reps. Most muscles in your extremities are composed of type II muscle fibers.

Phase of Training

General Adaptation Syndrome Weight Training

Your body has the ability to adapt to almost any activity. If you perform the same number of sets and reps without ever changing up your routine, your body will plateau.

A plateau is when your gains in fitness come to a standstill. Plateau is represented by the exhaustion phase of the General Adaptation Syndrome model on the right.

If you train properly, you should lift in phases. This is called periodization, and it is the basis the training program of all serious athletes, bodybuilders, and strength trainers. Periodization adjusts weight training volume to account for adaptation.

Simply put, periodization requires you to cycle through periods of higher and lower volume (sets and reps) in your training program. You can think of periodization as separate training periods of lighter weights and more reps alternating with periods of heavier weights and less reps.

How to Know Which Phase is Appropriate

Your Goals Determine Which Phase of Training You Should UseGeneral Adaptation Syndrome Weight Training

If your goals are more strength-related, you should be in the lower reps with higher weight phase for a majority of the time. If your goals are body composition-related such as weight loss or muscle gain / muscle toning, you should spend most of your time in the higher reps phase.

Even if you are not a competitive athlete or bodybuilder, you can benefit significantly from using the periodization model. With the science of weight training on your side, you will get optimal results by avoiding the frustrating plateau. Periodization also helps prevent overtraining syndrome.

You go through alarm, resistance, and adaptation phases of periodization before you take your active rest and recovery and start again. If you don’t follow the periodization protocol, you will most likely enter the exhaustion phase, which will hinder your results. The GAS or General Adaptation Syndrome is outlined in the chart above.

When to Switch Up Sets and Reps

Like most exercise-related issues, when to switch up sets and reps varies from person to person. Athletes who have strict strength and conditioning programs have a competition season around which to plan their different periods.

For a normal person just looking to be in great shape, the time to switch phases is when you start to plateau. When if you start to feel less energized after workouts, feel as if you’re losing strength, or get bored, it is a great time to take a short active rest before switching to the next training period.

Take an Active Rest Period Between Cycles

A very important part of periodization is rest. If you have been going with heavy sets and reps for a while and are ready to switch to a cycle of light sets and reps, a week of active rest will make a big difference to your success in the next phase.

Active rest means you can be active, but avoid structured exercise such as jogging and weight training. After you have your active rest period, the new phase of training will cause the alarm in which your body has to adapt to (lose weight, gain muscle). Check out our article on Active Recovery for Health and Fitness to learn tips for maximizing your recovery period.

Guidelines for Sets and Reps

The number of sets and reps you should perform is not set in stone. When you hear “low reps” it usually means 8 or less reps per set. “High reps” usually means 12-20 repetitions per set.

There is no complex formula to determine how many sets and reps you should perform. Sets and repetitions are a hotly debated topic in health and fitness field because there really is no absolute answer.

Some “experts” say that one set per body part is all you need. Other “experts” scoff at the first set “experts” and say that a single set is ineffective.

You Can Establish Your Own Guidelines for Sets and Reps

Trial and error is the only way you can determine which sets and reps scheme will work for you. There are many training modalities out there, and what works for someone else might not work for your, so it is best to try as many as you can to see which yields the most results.

Here Are Some Very General Guidelines to Get You Started:


2 Sets of 15-20 Repetitions

If you are a beginner, it is very important that your body learns proper form. During the beginning phase of weight training, your nervous system is being trained more than your muscles.

Your neurological system is not familiar with certain motions, so it is best to perform slow and controlled motions for a high number of reps. This will allow your neurological system to catch up to your muscular system.

Once your nervous system is able to recruit the muscle groups properly, it is time to increase the weight and move on to the next phase. It usually takes about a month for your body to neurologically adapt.


3 Sets of 8-12 Repetitions

Now that your nervous system has adapted, your muscles are ready to accept heavier loads. After the beginning phase, your muscle recruitment patterns are good enough to recruit a large percentage of your muscle groups during each exercise.

At this point, an extra set can be helpful if your goal is to develop larger muscles, also known as hypertrophy. An added set will increase your training volume.

During the intermediate phase, you will start to feel more fatigue in the targeted muscle during the exercise. During all your sets and reps, it is very important to feel the muscular contraction in the correct muscle so you know you are performing the exercise correctly.

When you lift for a given number of reps, you should choose a weight which you think you can lift only that many times and no more. If you can perform the desired number of reps without fatiguing, you may want to increase the weight for the next set. Remember that a perfect set is a set to failure.

You can be in the intermediate phase for years. Many people never become advanced weight trainers. You do not have to become advanced to get results from any exercise program.


3-5 Sets of 1-20 Repetitions

If you can control heavy and light weights with correct form and are comfortable with muscular failure, you can consider yourself advanced. At this stage you should be familiar with your own response to weight training.

Options are very open with regard to sets and reps for advanced weight trainers. To know the correct amount of weight to use for a strength-gaining program at the advanced level, it is important to determine your 1RM or 1 rep maximum for certain lifts. Once you determine the 1RM, you can accurately choose the amount of weight to use for a set of any number of reps with the load assignment chart.

As previously mentioned, whether you are advanced, intermediate, or a beginner, it is best to organize your training with the periodization model to get the best results and prevent injury.

sets and reps

Important Take-Home Information

You are NOT Lifting Weights, You are Contracting Your Muscles

You don’t win the pink stuffed elephant if you lift a certain weight 10 times. The prize you get for contracting your muscles is improved strength and endurance as well as a lean, toned body. Focus on a sets and reps scheme that gets you closer to your own goals, not on what other people are doing.

The Number of Sets and Reps is Not Set in Stone, So Use Trial and Error to Find What Works Best for You

Your body’s primary muscle fiber type due to your genetics helps determine how your body will respond to weight training. If your goal is to gain strength, you should definitely use the Load assignment chart to help you determine the number of sets and reps.

Rest as Little as Possible in Between Sets

Unless you are specifically trying to gain maximal strength, you should have minimal rest in between sets. Minimal rest between sets allows you to squeeze in the most volume in the least time, making your workout more time-efficient. In order to minimize rest between sets, there are different ways to organize your weight training set structure such as super-sets, tri-sets and giant sets.

Light Weights (High Reps) Do Not Tone, and Heavy Weights (Low Reps) Do Not Bulk

This is the most predominant fitness myth. A proper weight training program includes periods of low reps with heavy weights and high reps with light weights.

Whether your weight training program helps you tone or bulk up depends mostly on your diet, genetics, and sex. Women should not be afraid to lift heavy weights. Read our article on Health Benefits of Strength Training for Women to find out why every woman should be lifting weights.

Maximize Your Workouts by Manipulating Exercise Variables Such as Sets and Reps

  • Training Volume
    Training volume is the most important concept to grasp if you want to get the most benefits from weight training. Training volume depends not only on sets and reps, but exercise selection and lifting speed.
  • Training Splits
    To get the most out of weight training, make sure you understand how to structure training splits. A training split refers to which muscles or muscle groups trained each session. A good training split will help you achieve your goals more efficiently, allowing you to rest muscles while you are training others. Also learn about different types of special sets and reps.
  • Exercise Guides
    Look an anatomy chart of all the major muscles in the human body. Click on a body part to find some of the best exercises for each muscle group. Also click on the exercise ball or other pieces of equipment to find equipment-specific exercises.
    Dialing in your sets, reps, splits, and volume is one thing, but no well structured exercise program is complete without the proper health and nutrition to match. Check out many of the latest health trends here.

Load Assignment Chart

 load assignment chart

load assignment chart

How to Use Load Assignment Chart

The Load Assignment Chart is Very Useful for Strength Training Programs

You can find a very close estimate of the amount of weight you can lift from this chart. Use the chart for the major multi-joint lifts such as dead lifts, squats, bench presses, military presses, power cleans and pull downs. Do not use it for isolation exercises such as biceps curls.

The Load Assignment Chart is Most Accurate if you use your 1RM or 1 rep Maximum Lift

Say your 1RM of bench press is 380. You want to do a set of 6. You can consult the chart and know that 317.3 is the weight to use for 6 reps if you want to a set of 6. The weight suggested by the chart is usually just right. You do not have to perform a 1RM to use the chart.

The Load Assignment Chart is just as Useful for Estimating Your 1 Rep Max

If you perform a set to failure with any weight, you can consult the chart to estimate your 1RM. Say you squat 300 pounds and are just able to perform 8 reps before you cannot perform another rep. Scroll down to 300 under 8 reps on the chart and follow the chart over to the left. Your 1RM would be around 380 pounds.

If you’re serious about strength gains, it is a good idea to print out the load assignment chart and bring it along to the gym every time you work out.

The Load Assignment Chart is Also Useful to Help Determine Training Volume, Training Splits, and Exercise Selection

  • Weight Training Set Structure
    Overview of different options for structuring the sets you use in your weight training workouts.
  • Training Volume
    The amount of work done in a single workout. Training volume shows you a good estimate of your workout capacity.
  • Training Splits
    Which body parts to do each workout to allow for proper rest.
  • Exercise Selection
    Find a plethora of full-body exercises. Multi-joint exercises are best for weight loss.

Author Profile: Mike Behnken

Mike Behnken is a personal trainer who holds multiple NASM certifications and a MS in Exercise Science. Mike loves fitness, travel, and photography among many other interests.

Disclaimer: The views of the author are his or her own, and do not necessarily reflect the opinions of Ask The Trainer.
Did you enjoy reading my article? Please rate it below!

1 Star2 Stars3 Stars4 Stars5 Stars (8 votes, average: 4.75 out of 5)

Leave a Comment


©2018 All rights reserved. Terms of Use / Privacy Policy.

askthetrainer logo

Log in with your credentials

Forgot your details?