How often should you workout to build muscle? What’s too much? What’s not enough? And what is just right? The Barbell sought out the latest scientific consensus to find the best answers.

WORKOUT FREQEUNCY: A SHORT HISTORY

The trend has been pointing ever downward. Back in the 1970s, Arnold Schwarzenegger (seven Mr. Olympia titles) and many of his competitors worked most muscles three times per week! Afterwards and throughout the 1980s, twice weekly became the standard split. There were variations. Three-on, one-off was popularized by Lee Haney (eight Mr. Olympia titles) and Cory Everson (six Ms. Olympia titles), thus hitting body parts twice every eight days. And then came Dorian Yates (six Mr. Olympia titles), who dominated bodybuilding through much of the 1990s while only working body parts once weekly in four workouts. Those who didn’t follow his high-intensity training adopted his once-weekly formula but over six workouts.

how often should you workout to build muscle
Arnold in the ’70s.

And the six-days-per-week routine in which body parts are trained once weekly has been the most popular split ever since. Maximize focus (one body part per workout) and recovery (one week between workouts for body parts) to maximize growth, so the logic goes. But we’re skipping over the fact that, in Dorian’s wake, Ronnie Coleman (eight Mr. Olympia titles) reigned while, again, hitting body parts twice weekly—as if the revolution never was. Ronnie did a lot of growing while doubling up the workouts on the guys chasing him. Once weekly, twice weekly, somewhere in between, which is it? What’s the right workout frequency?

HOW OFTEN SHOULD YOU WORKOUT TO BUILD MUSCLE: THE STUDIES

First, let’s look at strength. Researchers published a systematic review of all relevant training frequency studies, 22 of them, looking at strength gains. They concluded: “[H]igher training frequencies are translated into greater muscular strength gains. However, these effects seem to be primarily driven by training volume because when the volume is equated, there was no significant effect of [resistance training] frequency on muscular strength gains.” In other words, if you do 16 sets for back in one weekly workout or 8 sets for back in two weekly workouts, the strength gains are virtually the same.

The researchers went on to state: “Thus, from a practical standpoint, greater training frequencies can be used for additional [resistance training] volume, which is then likely to result in greater muscular strength gains.” So, two weekly workouts of 16 sets for back would likely be more effective than one such workout, simply because the workload is doubled.

Let’s turn now to a systematic review of all relevant training frequency studies, 25 of them, looking at muscular gains. The researchers concluded: “Meta-regression analysis of non-volume-equated studies showed a significant effect favoring higher frequencies, although the overall difference in magnitude of effect between frequencies of 1 and 3+ days per week was modest. In conclusion, there is strong evidence that resistance training frequency does not significantly or meaningfully impact muscle hypertrophy when volume is equated. Thus, for a given training volume, individuals can choose a weekly frequency per muscle groups based on personal preference.”

So again, if you do 16 sets for back in two weekly workouts (32 sets total), the gains are greater than if you did 16 sets in one weekly workout. But, if you do 8 sets in both (16 total) the gains are the same as if you did 16 in one. In other words, the increased frequency does not lead to greater gains, but the increased volume does.

how often should you workout to build muscle
Dorian Yates in the ’90s.

Most of the previous studies were in untrained individuals. So, a newer study investigated the effects of workout frequency on trained men. One group hit every bodypart once weekly for 16 sets, and the second group hit every body part twice weekly for eight sets, so overall volume was the same. After eight weeks, no significant strength gain differences were noted between the two groups. However, there were some minor muscle size advantages in the second group. According to the researchers, this suggested “the potential of a slight benefit to the higher training frequency.”

HOW OFTEN SHOULD YOU WORKOUT TO BUILD MUSCLE?

The science says there is a slight advantage in muscle growth to hitting body parts more frequently than once weekly. This is mostly, but not entirely, due to the increased training volume. Note that your split does not need to be spread over seven days. If you spread it over five days (four-on one-off) or six days (five-on one-off) you can increase workout frequency over once-weekly and serve up rotating off days. You can also spread it over seven days (six-on one-or-two off) but repeat one workout (at least some of the time), focusing more on the one body part you want to bring up the most. (See: Priority Training Principle for more on this.) Most importantly, make sure you thoroughly work all muscles at least once weekly. After that, adopt the routine that works best with your schedule.


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