This is one of the most common questions that a gym goer asks? How many repetitions should I do? The standard answer you get is to go for fewer reps using heavy weights for strength & size and lighter weights for higher number of reps to improve muscle definition. Hold on, this is not totally true. Read on here to find out what number of reps (higher or fewer) you need to do for each exercise to achieve the different goals.

The number of reps we do has a major stimulus on the end results we achieve from a workout program.

In order to maximize the efficacy of your time in gym, here are the most important 7 tips that you should consider while deciding the number of reps you should do depending upon your fitness goals.

1. What Is A Rep: A rep is acronym for repetition. A rep is one complete, motion of an exercise by the muscle involved at the joint or series of joints. Every rep involves 3 specific phases of a muscle action: shortening (concentric), a momentary pause (isometric) and a lengthening (eccentric).

For instance, in case of a bicep curl using a dumbbell, a rep is one complete movement starting with your fully extended arm with your hand down by your leg, then flexing (bending) your arm (with your elbow joint acting as a hinge) until your hand reaches up toward your shoulder, then slowly extending your arm back down to the starting position: that’s one repetition.

2. Momentary Fatigue: Whatever your personal fitness goals may be; the more important is to perform reps until you achieve a moment of muscular fatigue than the number of reps you do.

You achieve a momentary fatigue in your muscle when you are not able to perform 1 more rep and all of the muscle fibers responsible for moving that muscle have been recruited. For example in case your goal is to increase muscle mass and you feel capable of doing a couple of more reps at the end of a given set, it would mean that you have not momentarily fatigued all of the type II fibers responsible for building muscle mass. This means you will not be working out in the most possible effective manner to achieve your goals, meaning your efforts and time – both are wasted.

3. Weight And Reps Relationship: Generally, the number of reps you perform for any exercise is inversely related to the amount of weight you use. As you increase the weight, the number of reps you would be capable of performing decreases. Thus, whereas lower-intensity loads can be moved for higher reps, the higher-intensity loads can be performed for a relatively low number of reps, before fatigue sets in.

4. Muscle Maximum Strength Goal: Working out for strength, one needs to use heavier weights, which resultantly restrains the number of repetitions that one can do. A heavier load, as a matter of course, engages more type II fibers of the muscles that you are training. Type II fibers use anaerobic (non-oxygen based) metabolism, which supplies only a limited amount of energy. This is another reason that explains why heavy loads can be moved only for a few repetitions at a given time, meaning the muscle simply runs out of available energy relatively in shorter periods. If your aim is to increase strength then you should use greater weights that cause momentary fatigue after no more than six reps.

Recommended Number Of Reps: < 6

5. Muscle Definition (Size & Mass): Training for definition can be achieved by a different “rep-ranges”. The number of reps is not as important as the length of time during which the muscle stays under tension. The type II fibers responsible for strength are also responsible for providing definition to the appearance of muscle. Definition comes from a muscle maintaining a state of semi-contraction, which is achieved by keeping a muscle under tension for a longer period of time. A higher numbers of reps performed at a slower movement speed can facilitate the tension needed to increase definition. No matter how many reps you decide to use, to achieve definition you must reach a state of momentary fatigue – which means you’re not capable of performing another rep.

Recommended Number Of Reps: 6 – 12

6. Endurance Goal: For sports such as running, cycling, swimming, etc., aerobic endurance is very important. To increase aerobic/cardiovascular endurance, you will need to do strength training that recruits and activates type I muscle fibers. Type I muscle fibers depend upon aerobic metabolism (oxygen based energy path). This type of muscle fibers is engaged when you do as many as 20 to 30 reps, which resultantly can be done using lightweights only. In other words for aerobic endurance, you should use lightweights for higher number of reps.

In this case, training until you reach fatigue is not needed, because our aim is neither to increase strength nor muscle mass. Rather, we are trying to increase endurance; so actually, we want to avoid working to fatigue. However, the rest intervals have to be kept relatively short to make sure that the workout causes the necessary stimulus to activate your aerobic metabolism.

Recommended Number Of Reps: > 12

7. Muscle Power Goal: Muscle Power means ability to generate substantial amount of muscle force in the shortest possible amount of time. It requires a skill that needs specific programming to acquire power. But, one should be careful while performing such a specific training program. You need to use the appropriate number of reps to perform power training in a safe manner.

Training for muscular power puts massive mechanical & metabolic demands on the involved muscle and rapidly fatigue the nervous system that maintains proper joint mechanics.

When performing power training such as barbell snatch, push press, or clean-and-jerk, etc., the emphasis should be on the form & technique of the movement, and not on the number of reps performed. For safe, efficient power training, the number of repetitions should 1 or 2, at the most should not more than 4 or 5 in certain specific cases. Doing reps more than the prescribed number compromises on quality, and so considerably increases the risk of injury.

As in case of endurance training, the key element of power training is NOT to reach fatigue, but to do the appropriate number of reps using the best form & technique.

Recommended Number Of Reps: > 1 or 2 for explosive lifts; Jumps and medicine ball throws < 8 

Appropriate Rep Numbers to Achieve Specific Goals

Training Goal



> 12

Muscle Definition

6 -12*

Maximum Strength

< 6*


(i)    Explosive barbell lifts

(ii)  Jumps and medicine ball throws


(i) 1 – 2
(ii) < 8

* For best results, the last rep should achieve momentary fatigue.


Useful Related Post: Low Reps vs. High Reps   

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