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How Long Should a Workout be to Build Muscle?

OH! This question is fraught with controversy!

Some say 45 minutes, others an hour, some say even 2 hours, while there are those who say it should be as long as it needs to be.

So where do we start?

Let’s start with the end in mind.

The Goal: Build muscle

tyre flipping hardcore workout

How is muscle built?

I discussed in a different article that muscle is built on the eccentric contraction.

There are three contractions that make up every lift. Concentric, Isometric and Eccentric.

In terms of a barbell curl:

  • Concentric is lifting the bar to your chest.
  • Isometric is holding the weight in a fixed position at your chest
  • Eccentric is lowering the bar back down.

It is during that eccentric movement that muscle damage occurs, prompting growth.

So, what does this mean for YOU?

It means you need to focus as much time on the concentric flex as you do the eccentric motion.

Which brings us to our second point

Time under tension

doing push up exercise with dumbells

Time under tension is just what it sounds like, the time the muscle is under tension. Some body builders recommend that in order to build muscle, the muscle should be kept under tension for 40-60 seconds for each set.

If a set is 10 reps, each rep should be 4 to 6 seconds.

In addition to that:


Tempo, pacing, whatever you call it, is important. If each rep is 4 seconds, count two seconds o the concentric move and two seconds on the eccentric. If the set is 60 seconds, count three seconds on the way up, and 3 on the way down.

One Easy Fix To Build Muscle Faster

Vince with V Shred demonstrates the concept of tempo and time under tension in this video. I think he is spot on in his muscle building technique and believe it is a solid video. Highly recommended video.

OK, so a muscle building set needs to be between 40 to 60 seconds where does that put us in terms of overall workout time needed?

Another video by Vince with V Shred that lays out the facts in a way that is easy to understand.

Basically, there are two types of lifting workouts:

  • Strength Workout = getting STRONGER
  • Hypertrophy workout = Gains!

Since we are answering the question “How long should a workout be to build muscle?” lets look at a Hypertrophy or muscle building workout.

Hypertrophy defined: An increase in size or volume of muscle due to an increase in cell size.

Anatomy of a Hypertrophy workout

Hypertrophy requires that the bodybuilder use sub-maximal weight. In other words, less weight than the maximum they are able to lift.

The rest time between sets will also be shorter, since maximum weight is not used. The time for each set is also longer, since time under tension needs to take place.

Warm up time: recommend one min for each set planned. In this example we are doing 15 sets. So warm-up can be 15 min.

Number of Reps per set: for hypertrophy it should be between 10 to 15 reps per set. We will go with 12

Total number of sets for hypertrophy should be between 10 and 20. W will use 15. Since they should be between 40 and 60 seconds, that gives us a maximum of 15 min.

Rest time will be less that it would be for a strength workout. 45 seconds to a minute. At most, 15 minutes.

body builder

Can you build muscle with a 45 minute workout?

Well folks, looks like the 45 minute workout for building muscle seems reasonable, if you workout at home with 0 distractions, no potty breaks, no time waiting for equipment or chatting with buddies, no mirror time or time setting up equipment.

Let’s be realistic

But we live in the real world, and are by nature social creatures. Half the appeal of going to the gym, according to some gym goers, is catching up with friends and socializing.

Plus, you know, maybe time for a selfie or two, just to check form.

So, How long should a workout be to build muscle?

While I admit, yes, technically, it can be done in 45 minutes, my personal opinion is it could take anywhere from 1 hr to an hour and a half. And if it takes longer, who am I to judge. I’m not your mom, right?

Let us know below in the comments how long your workouts have been lately.