Asking how many days per week should a muscle be trained, is like asking how many days a week you can eat sweets. We need so much more information to answer that question appropriately.
What does your entire diet look like with training?
We have to consider total volume and other training factors in order to answer that question, which is what we are going to go over in today’s blog.
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If you want to maximize hypertrophic effects (if you want to build muscle), today we are strictly looking at training frequency.
Of course, there are nuances that we have to consider because days per week is not the only training factor that will lead to building muscle.
My short answer to these questions are:
Let’s turn to some scientific literature to help us answer this question.
The study pictured above was a systematic review and meta-analysis to determine the effects of resistance training frequency on hypertrophic outcomes, meaning:
And this is what they concluded with that meta-analysis.
The current body of evidence shows that frequencies of training twice per week promote superior hypertrophic outcomes to once per week.
Whether training a muscle group three times per week is superior to twice per week protocol remains to be determined.
This meta-analysis was done back in 2016. Perhaps there is more up-to-date evidence to suggest that 3 days per week is superior to 2. I know that another review was conducted, I want to say two years later that found some faults in this study being the testing methods were direct versus indirect, a test of hypertrophy.
Also that it was a very small meta-analysis only taking into consideration 10 studies. I presume that it’s actually less about the days per week and more about overall work volume.
That would be my hypothesis and I am fully willing to be wrong about that if other data is presented.
This other study (pictured below) was done more recently in 2022 is a much larger systematic review including over 2000 studies and with a minimum of six weeks of training. Compared to the four that were from that previous meta-analysis.
Obviously you can perform the same amount of total volume in one day per week as you can in two days per week. That’s why I like the idea that we should look at total volume versus days per week or training frequency.
For reference, they were looking at the triceps and biceps, but I do believe we can likely apply that same idea to other muscle groups.
And one of the more recent studies I saw (that I couldn’t seem to locate to link here) found no difference between training once per week or twice per week, but it was the same total volume in training once per week and twice per week.
So that kind of supports my hypothesis…
Training twice per week does not benefit you unless you are doubling or close to doubling your total work volume in those two training sessions. And if you’re familiar with or know what study I’m referring to that I wasn’t able to find, drop it in the comments below.
A common upper-lower split, for instance, allows you to train a muscle group twice per week and only train a total of four days.
You could argue that you would get even better results by training the same muscle group, the same weight twice per week… Like you would see in a classic six-day-per-week bodybuilding split that would look something like this:
And then simply repeat that again for three more days that week with one day of rest in between (three on, one off split).
In a four-day-per-week upper lower split, you’re going to train upper body twice per week and lower body twice per week, but you are hitting the same muscle groups through carryover… Not by directly training that twice per week.
The split could be squat, hinge, push pull. It could also be general upper body and lower body where you are hitting a bit of everything on both upper body days as well as lower body days.
But generally speaking, it’s a pretty safe way to put on muscle in terms of choosing your training split.
It’s not going to be as muscle group specific, like classic bodybuilding. But in training, horizontal pressing, we still touch on the shoulders, whereas the shoulders are going to be the main focus and the prime movers on a vertical pressing day and where the lats are going to be the prime mover on a vertical pulling day… The lats are still going to be recruited in horizontal pulling patterns like rows.
Therefore we are still touching those muscle groups twice per week and they’re getting in those 12 to 20 sets per week. Even if the muscle that you’re working is not the main focus.
You may have a lower body day that is more Quad focused and another lower body day that is more Glute focused, but we are still recruiting the glutes and the hamstrings in squatting patterns, and you could add in quad accessory work to a more hinge dominant day.
If you’re pushing them hard twice per week, you’re in a good place for building muscle.
If you’re working at high enough intensity in all of these exercises, you can probably count on a solid hypertrophic effect. By intensity, I’m referring to load, so using challenging weights and working close to fatigue.
So don’t stress if you are only able to train 3 days per week. It will absolutely be easier to put on muscle training 4-6 days per week.
While you could easily maintain muscle mass training three days per week, it might just be a bit harder to actively put on muscle mass.
I will say the only time that I’ve ever been able to actually build a noticeable Bicep in my life was when I was training them 3 days per week. That’s just what it took for my genetics. Take it for what it’s worth. Whereas if I train my Deltoids once per week, I can pretty easily add on muscle mass in that area.
So take your own genetics into account. Frequency and total volume isn’t always the answer, but in terms of building muscle mass, it’s clearly an important part of the equation.
Don’t overcomplicate it.
Go ahead and let me know in the comments below how many days per week you’re currently training and how many days per week you are training a specific muscle group.
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I'm an adventurous introvert from Vancouver, Washington who lives on sleep + "me time." I'm a lover of lifting weights, dinosaurs, real talk and traveling with my husband. I am here to help you move better, lift more, bust the myths of the fitness industry, and inspire you to love the process.
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