How Many Sets and Reps Should I Do? Scientific Breakdown

Trying to figure out how many sets and reps you should be doing to maximize your muscle gains in the gym is usually the first thing people ask when they start working out.

It’s also a hotly debated topic among seasoned weight lifters with years of experience and everyone has an opinion. Unfortunately nobody has the same opinion so trying to find a general consensus is virtually impossible.

Everyone has different biological make up, we all have a different mix of slow and fast twitch muscle fibers and exactly what works best for you to some extent is going to be unique to both your body and the time you have to put into it.

With that said, a couple of newly published case studies on experienced lifters have really shed light on what works best for most people and that is what I recommend your starting point is when trying to figure out what is best for you.

Who is this for?

Before I jump into the case studies I want to point out these were done on experienced lifters. If you are in your first year of weight lifting, you may want to ease into a higher sets and reps volume or you could risk extreme soreness that is more of a setback than a benefit.

This article is for experienced lifters who want to pack on muscle and strength as fast as possible.

Without further ado here is how many sets and reps a week science says you should be doing to build muscle fast.

Volume – How many sets and reps should I do per week per muscle?

In a recent 8 week, 2 part study that just concluded in December of 2019, resistance trained men were divided into 3 groups and measured for muscular strength and hypertrophy. (1)

The men’s diets were monitored to ensure no dietary difference could have an effect on the outcome and exercises in all 3 groups were identical but the volume was changed depending on which group they were in as follows:

1. 16 sets per muscle group per week
2. 24 sets per muscle group per week
3. 32 sets per muscle group per week

All exercises done were in the 8 – 10 rep range and the men supposedly trained each set to momentary failure.

The “momentary failure” part I highly doubt as the idea even a highly trained athlete could perform 8 sets of squats of 8 – 10 reps each to failure as they did in the study, is suspect at best.

It is even more suspect knowing the men only had a 1 min rest given in between sets!

There has also been a very good recent study showing that constantly training to failure when you are using higher rep ranges (6+ depending on the exercise and muscles worked) actually does more harm than good which we will discuss later in this article.

For now, let’s just assume the men trained to “voluntary failure” or that they likely had 1 – 2 reps left to give at the end of each set.

You can see the exact workout regimine utilized in the study in the following image.

Hypertrophy

At the end of the study the following hypertrophy was noted by percent of increase in each of the 3 groups:

Group 1 – 16 Sets

• Biceps – 0.5%
• Triceps – 0.8%
• Quads – 2.1%

Group 2 – 24 Sets

• Biceps – 1.3%
• Triceps – 4.0%
• Quads – 5.6%

Group 3 – 32 Sets

• Biceps – 3.1%
• Triceps – 7%
• Quads – 9.4%

As you can see the arms barely grew at all for group 1 but saw huge growth for group 3. In fact, the biceps for group 3 grew a whopping 520% more and the triceps 775% more!

The quads also grew significantly more for the 32 set group gaining an astounding 347% more size. For most men, legs are the hardest body part to add size to so this is really quite an incredible find.

Strength

Strength was measured by pre and post 1 rep max in the bench and squat. Here is how the 3 groups performed.

It’s interesting that group 2 saw the weakest overall bench increase, however, the important part of this is the high volume group saw significantly bigger strength gains.

Important note: In this study there was only 1, not 2 tricep or bicep isolation exercises performed. The bench press is a compound movement that works the triceps in addition to the chest so only 1 isolation movement was needed for the triceps.

This is one reason I am so big on focusing primarily on compound exercises as discussed my article here.

So this study settles the argument and 32 sets / 8 – 10 reps / 1 minute rest is the best way to go right?

I certainly think it’s worth trying it for yourself for a couple months and seeing how your body responds but before we crown this the absolute king of programs let’s look at a couple more things.

Rest Period – How long should I wait between sets?

As mentioned the men in the above study were only given 1 minute of rest between sets. Personally I tend to like short rest periods just for the fact I’m a busy guy and can get my workout in quicker and get on with my day.

If you are going to tackle a 32 set per muscle group program, unless you are retired or have a great trust fund, you will probably have to stick to that yourself. Nothing wrong with that, as the men in the study obviously had incredible results.

However, in another recent study on resistance trained men, it was found that longer rest periods of 3 minutes gained more size and strength than men who only received a 1 minute rest period. (2)

This is believed to be true because longer rests allow you to keep more weight on the bar which means more tension on the muscles.

Could it be possible that men doing a 24 set routine with 3 minutes rest between sets performs as well or even better than the 32 set routine with just 1 minute rest?

We will have the wait for that study to come out but I’d really like to see the results.

Rep Tempo – How fast should I lift?

The men in the first study lifted at a rep tempo of 1.5 second concentric/eccentric tempo.

This means they lowered the weight over 1.5 seconds and lifted the weight back up at 1.5 seconds or that they basically just performed the exercises at a normal pace.

However, studies show that performing exercises with a slower eccentric (lowering phase) tempo of 4 seconds vs 1 second, results in both increased hypertrophy and strength gains. (3)

This is believed to be due to a muscles “time under tension” and that actually may be why in study 1 the highest training volume resulted in the best results. The 32 set group simply had more total time under tension than the 16 set group.

Important note: The concentric (lifting phase) tempo does not affect strength or hypertrophy.

Is it possible that men performing 16 sets per muscle group using a 4 second eccentric phase AND taking 3 minutes between sets could perform as well or better than the men showcased in our first study using 32 sets with a 1.5 eccentric phase and 1 minute of rest?

Once again, I’d really like to see a large scale study done so we could find out but I think it would be worth you trying this out for yourself to see how your body responds.

Intensity – Should I train to failure?

As mentioned above the idea the men in study 1 trained to momentary failure is almost silly. Would it have been better if they had? Let’s see what science says.

There have actually been multiple studies now showing that training to failure produces worse results than going to about 80% on average.

A recent study published in 2 parts took an in-depth look strength and hypertrophy in men who train to failure and those who don’t push it to their absolute max. (4, 5)

Their findings were in line with all the previous research which suggests training to failure may do more harm to your body with no potential benefits.

In fact the men in their study who did not train to failure saw “greater improvements in vertical jump, rate of force development, and maximal strength” as well as “increased muscle hypertrophy”.

Training to failure may result in increased injury risk, increased recovery time needed and increased energy drain that can affect the rest of your day and/or week.

Plus every exercise you go to failure just takes that much more energy out of the rest of your workout and each subsequent exercise could have a lower total power output which of course is suboptimal.

Conclusion

It’s clear the men in study 1 had amazing results and if you have the ability to follow that same program or are willing to work your way up to that volume level, you are probably going to have amazing results too.

We also know that science suggests taking more time between sets and utilizing a slower eccentric lifting phase is better for both hypertrophy and strength too.

However, you would have to be an absolutely genetic freak or on heavy steroids to even think about implementing a 32 set per muscle group routine along with the slower eccentric phase and extra tension allotted from a 3 minute rest period.

For most men, it really comes down to what will provide the best results in the least amount of time.

The only way to know what will work best for YOUR body and your schedule is to experiment with it. Only you can give yourself the correct answer here.

What we can say for certain though is training to failure is not going to benefit your workout so at least you can cross that off the list and save yourself the additional pain and recovery time.

References

1. High Resistance-Training Volume Enhances Muscle Thickness in Resistance-Trained Men. Brigatto FA, Lima LEM, Germano MD, Aoki MS, Braz TV, Lopes CR. – Link
2. Longer Interset Rest Periods Enhance Muscle Strength and Hypertrophy in Resistance-Trained Men. Schoenfeld BJ, Pope ZK, Benik FM, Hester GM, Sellers J, Nooner JL, Schnaiter JA, Bond-Williams KE, Carter AS, Ross CL, Just BL, Henselmans M, Krieger JW. – Link
3. Resistance training with slow speed of movement is better for hypertrophy and muscle strength gains than fast speed of movement. Pereira, Paulo Eduardo & Motoyama, Yuri & Esteves, Gilmar & Quinelato, William & Botter, Luciano & Tanaka, Kelvin & Azevedo, Paulo. – Link
4. Divergent Performance Outcomes Following Resistance Training Using Repetition Maximums or Relative Intensity. Carroll KM, Bernards JR, Bazyler CD, Taber CB, Stuart CA, DeWeese BH, Sato K, Stone MH. – Link
5. Skeletal Muscle Fiber Adaptations Following Resistance Training Using Repetition Maximums or Relative Intensity. Carroll KM, Bernards JR, Bazyler CD, Taber CB, Stuart CA, DeWeese BH, Sato K, Stone MH. – Link