Low Reps or High Reps for Building Muscle?
Ahhh the chicken or the egg debate of gym goers: High reps with low weight or low reps with high weight? WHICH IS IT? It’s a bro science battle that has continued since the beginning of gym time…..
So who’s right? Lovers of low reps or heralds of high reps?
Well, the verdict is in.
Science will be the decider here. Be ready to have your mind blown.
Low Reps versus High Reps
Squaring off in the left corner is a long-loved by physique competitors, LOW WEIGHT, HIGH VOLUME with the confidence of an Apex predator at a water hole full of obese Elk.
In the opposing corner, weighing in at 90 percent of your personal best is HIGH WEIGHT, LOW REPS, a big bodybuilder’s swolemate.
Who will win this long awaited fight? Who will finally tap out and put this debate to bed?
That’s for science to decide.
Referee? We’re ready.
LLLLLLLLET’S GET READY TO CCCCCCRUMBLE (someone’s theory)
Resistance Training and Body Response
Resistance training stimulates muscle growth and strength. It also elicits responses from the body that can work for or against us. Metabolic stress, in particular, can result in increased activation of fast-twitch muscle fibers (that’s a good thing) or increased levels of lingering cortisol (that’s a bad thing.)
So when it comes to working out—most people will complete three sets of 10 reps for each exercise.
This is pretty standard. But if you’re in the bodybuilding world—it might not be. Some bodybuilders swear by low weight high reps. Other bodybuilders swear by high weight low reps.
So which is it?
It’s about to get controversial up in here.
Scientific Studies on High Reps Low Volume and Low Reps High Volume
In an extremely thorough study conducted in 2015 over 8 weeks using with body measurements, ultrasounds, blood samples and more, finally achieved the answer we have all been waiting for.
Their intent was to compare moderate intensity high-volume training using short rest intervals with high-intensity, low volume training using long rest intervals in trained individuals (that last part is important—trained athletes bodies’ don’t respond the same way as trained.)
The Low Reps High Volume (HIGH) group performed four sets of 3-5 reps at 90% of their maximum weight with three minute rest periods. The High Rep Low Weight (LOW) group performed 4 sets of 10-12 reps at 70% of their maximum weight with one minute rest periods.
- No differences in ‘absolute strength’ but the HIGH weight LOW Rep group had significant improvements in max bench press weight.
- Changes in muscle sizes showed HIGH weight LOW rep groups nearly doubled lean arm mass compared to LOW weight HIGH rep group.
- Twice as many participants in HIGH weight LOW rep groups experienced significant changes in overall lean body mass and lean leg mass.
- As for cortisol, the results-stunting nemesis, the LOW weight HIGH reps had a greater cortisol elevation and response and it remained higher after subsiding than in the HIGH weight LOW rep group.
So what does this mean?
You might be wasting your time on longer sets/more reps if you want to build lean mass.
The results showed that that 8 weeks of high-intensity, low-volume resistance training with longer rest periods produces more lean mass and power (IRM bench press). Boom.
There’s your answer.
Don’t go just yet, we’ve got a little bit of science behind why this is the case.
Metabolic Stress of Training
We’ve all heard about the stress training puts on a body, but it’s the most influential factor in changes in muscle size and your body.
Metabolic stresses stimulate muscle hypertrophy and increases strength. With increased intensity during exercise, it activates fast-twitch muscle fibers.
Fast twitch, or type II, muscle fibers are used in powerful, quick movements like sprinting. To understand the difference between slow-twitch and fast-twitch, look at the difference in the legs of sprinters and long distance runners. Slow-twitch are endurance muscles; fast-twitch are power muscles. They are bigger but fatigue faster.
The only way to activate fast-twitch muscles—is to increase intensity. This induces a metabolic stress response that induces muscle growth and strength because it has a hypertrophic effect of acute anabolic hormone responses.
What does that mean?
Type II muscle fibers are like the Guidos of muscles—they take care of the fast dirty work when you need them. That’s it.
Need more proof?
In one study, back squat strength was significantly improved in HIGH weight LOW rep groups of nearly twice as much, upper body muscle endurance was sixteen times greater, and power increase was three times as much as the LOW weight HIGH rep group.
And, in a very strange study of only studying SETS, not weight, it found the ONE SET group had the same increases in strength, but the one set produced pronounced fat loss. Whhaaaat?
Yeah, it found through seven different skinfold thickness tests that the one set group had twice as much fat loss.
How is this possible?
Well, it’s possible in one study, with every result there are one hundred to say ‘it ain’t so’.
But, it’s pretty compelling that over 8 weeks with 7 different tests, the result was the same—one set is better than three sets.
So, are we all going to spend a lot less time in the gym because of this?
We’d say NO. Training isn’t just about muscle growth and strength. It’s necessary to be healthy, ya nut.
So don’t go cutting your gym time down to 15 minutes. Just consider increasing your weights, lowering your reps and adding more exercises to your schedule.
If you don’t agree with any of this—leave a comment. But remember, you’re arguing with science, not us.
Increase your gains even more with scientifically backed muscle-building supplements here. Now, go do something that makes you sweat.