So, you want to work out like Arnold Schwarzenegger on a bro split. Or maybe you want to train using the most scientific split that will maximize hypertrophy (i.e. muscle growth). Bodybuilders are the kings of building muscle. One study surveyed competitive bodybuilders and found approximately 69% of them trained each muscle group once per week [9]. There must be something to this right?
The evidence suggests that how often you work out does not influence muscle growth. Therefore, you can work out as little or as much as you please. However, approximately 10 sets have been suggested the upper limit per workout before workout quality is reduced meaning you will need to work out more than once a week to get adequate training volume for muscle growth.
So, let's dive straight into the research and flesh out exactly how often you should work out to build muscle.
Table of Contents
How Long Should You Workout To Build Muscle?
The American College of Sports Medicine recommends novice lifters workout 2-3 days a week, intermediates 2-4 days a week, and advanced lifters 4-6 days a week [1]. However, this does not specify how often each muscle group would be trained.
So, let’s take a trip back in time and walk through each stage of evidence so we can see how we get to the current consensus on training frequency for muscle growth. Starting with Brad Schoenfeld’s landmark meta-analysis in 2016 [2].
Many of today's muscle-building frequency recommendations are based on this one meta-analysis (the gold standard of research where multiple studies that meet the inclusion criteria are combined into one creating one large study). Their findings were that training a muscle group twice per week is superior to training a muscle group once per week.
However, one must note that at the time of publication, there were only 7 studies that met the inclusion criteria for the review and some of these studies were not randomized controlled trials due to not randomizing the training groups. Further, only 2 studies measured muscle growth directly. This means that the findings of this meta-analysis must be interpreted with caution due to the quality of studies available.
The following year, researchers doubled down on this theory suggesting that spreading out your training volume (i.e. splitting a workout you would usually perform in one day over two days) would optimize muscle protein synthesis through more frequent stimulation [3].
Meaning, if you can train a muscle more often - theoretically, you should spend more time in an anabolic state due to constant muscle repair.
Since then, more research has shed light on this topic so a new 2018 review was performed that included 10 studies measuring muscle growth directly and 18 measuring indirectly totaling 28 studies on training frequency [4].
The authors concluded that the amount of muscle growth is more influenced by training volume (i.e. how many sets and reps) than workout frequency, at least up to four days per week. At this point, it is unclear whether working out six or seven times per week spurs any more muscle growth than twice a week when the volume is equated.
But it seems that the theory about stimulating muscle protein stimulus does not hold weight. Fast forward to 2019, and we have our latest meta-analysis investigating training frequency and building muscle [5].
This is the most comprehensive review of the lot only including studies that were 6 weeks in length or greater while directly comparing muscle group training frequency.
They found strong evidence to suggest that weekly resistance training frequency does not have any meaningful impact on hypertrophy. This was regardless of adjusting for being trained or untrained, or upper and lower body. Safe to say, the evidence refutes the muscle protein synthesis hypothesis.
All of these reviews focus on volume equated training frequency. Meaning that regardless of how many times a week the subjects worked out, they would perform the same weekly number of sets per muscle group. This is the only way to truly get an accurate outcome.
When volume is not equated, we see a slight advantage to higher training frequencies [5]. For example, a total body routine training muscle groups five times a week was found to be superior to a split routine only training the muscle groups once [6].
The total body group performed more volume than the split routine group. This suggests that frequency can be used as a tool to increase training volume, one of the major drivers of hypertrophy.
There is also an individual response to exercise that must be considered. In a study that compared 2-3x a week and 5x a week leg extensions, there was a diverse range of responses [7]. 31% of these subjects saw greater muscle growth in the 5x a week protocol whereas a different 37% saw better gains in the 2-3x a week protocol.
This was even with the 5x a week protocol performing more training volume. Therefore, how often you work out will come down to personal preference, the time you have available to train, and which training frequency you respond well to.
One last consideration for how often you should workout is the number of sets per muscle group is optimal per workout. It has been suggested that 10 sets per muscle group per workout should be treated as the upper limit before the quality of your workout diminishes.
So, if you are only working out twice a week, it would be beneficial to train the same muscle groups in both workouts to maximize the hypertrophy response.
Should You Workout Everyday To Gain Muscle?
Based on the available evidence, you can work out every day and gain muscle. All that matters is your total training volume per muscle group. We know that anywhere from 7-25 sets per muscle group, per week, is a range that will elicit muscle growth.
Therefore, whether you split that over all 7 days (e.g. 1-2 sets of squats every day) or you train different muscle groups each day, you can make similar gains. However, be aware that sets should be taken relatively close to failure to maximize the hypertrophy response so training a muscle group every single day would become very difficult and potentially, sub-optimal.
How Many Days A Week Should You Workout To Build Muscle For Females
Whether you are male or female, these workout frequency guidelines remain the same. That is, training frequency does not affect muscle growth. Therefore, how many days you work out will be a personal preference.
Here is how you could choose your splits based on the number of days a week you'd like to work out.
3 Day Total Body Split
Monday: Full Body
Tuesday: Off
Wednesday: Full Body
Thursday: Off
Friday: Full Body
Saturday: Off
Sunday: Off
4 Day Upper/Lower Split
Monday: Lower Body
Tuesday: Upper Body
Wednesday: Off
Thursday: Lower Body
Friday: Upper Body
Saturday: Off
Sunday: Off
6 Day Push/Pull/Legs
Monday: Push
Tuesday: Pull
Wednesday: Legs
Thursday: Push
Friday: Pull
Saturday: Legs
Sunday: Off
How Often Should You Workout To Get Stronger?
It seems the same rules apply to strength as it does for building muscle. That is, when volume is equated, training frequency has no effect on muscular strength [8]. Meaning as long as you are performing a set number of sets per muscle group per week, it doesn’t matter if you do this over 1, 2, 3, or 4+ days.
Also, just like the muscle-building guidelines, frequency can be used as a tool to increase training volume which is important as higher training volumes from higher frequency result in greater strength gains.
References
1. American College of Sports Medicine. (2009). American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Medicine and science in sports and exercise, 41(3), 687-708.
2. Schoenfeld, B. J., Ogborn, D., & Krieger, J. W. (2016). Effects of resistance training frequency on measures of muscle hypertrophy: a systematic review and meta-analysis. Sports Medicine, 46(11), 1689-1697.
3. Dankel, S. J., Mattocks, K. T., Jessee, M. B., Buckner, S. L., Mouser, J. G., Counts, B. R., ... & Loenneke, J. P. (2017). Frequency: the overlooked resistance training variable for inducing muscle hypertrophy?. Sports Medicine, 47(5), 799-805.
4. Grgic, J., Schoenfeld, B. J., & Latella, C. (2019). Resistance training frequency and skeletal muscle hypertrophy: A review of available evidence. Journal of science and medicine in sport, 22(3), 361-370.
5. Schoenfeld, B. J., Grgic, J., & Krieger, J. (2019). How many times per week should a muscle be trained to maximize muscle hypertrophy? A systematic review and meta-analysis of studies examining the effects of resistance training frequency. Journal of sports sciences, 37(11), 1286-1295.
6. Zaroni, R. S., Brigatto, F. A., Schoenfeld, B. J., Braz, T. V., Benvenutti, J. C., Germano, M. D., ... & Lopes, C. R. (2019). High resistance-training frequency enhances muscle thickness in resistance-trained men. The Journal of Strength & Conditioning Research, 33, S140-S151.
7. Damas, F., Barcelos, C., Nóbrega, S. R., Ugrinowitsch, C., Lixandrão, M. E., d Santos, L. M., ... & Libardi, C. A. (2019). Individual muscle hypertrophy and strength responses to high vs. low resistance training frequencies. The Journal of Strength & Conditioning Research, 33(4), 897-901.
8. Grgic, J., Schoenfeld, B. J., Davies, T. B., Lazinica, B., Krieger, J. W., & Pedisic, Z. (2018). Effect of resistance training frequency on gains in muscular strength: a systematic review and meta-analysis. Sports Medicine, 48(5), 1207-1220.
9. Hackett, D. A., Johnson, N. A., & Chow, C. M. (2013). Training practices and ergogenic aids used by male bodybuilders. The Journal of Strength & Conditioning Research, 27(6), 1609-1617.