Move those muscles — but how often?
When it comes to exercise frequency, the rule of thumb is to perform some form of aerobic exercise most, if not all, days of the week. While there’s plenty of debate about how long each bout of exercise should be, 10 to 30 minutes of sustained physical activity (depending on intensity) is usually considered sufficient.
Ask the same question about weight training, and the answer isn’t as simple. The American College of Sports Medicine suggests a minimum of two strength workouts a week, with the acknowledgment that more are likely needed if the goal is to improve muscle size and strength. The recommendation leaves plenty of room to experiment with training frequency, but individuals are further advised to allow muscles
48 hours to recover before heading back to the weight room. Too fast a return jeopardizes results, say the experts.
But like any exercise-related recommendation, there’s science and then there’s practice, with plenty of gym rats and personal trainers recommending hitting the weight room most, if not all, days of the week.
Keep in mind that in cardiovascular conditioning, the primary muscle being trained is the heart. In the weight room, however, discussions about frequency revolve around how many times a week a given muscle or set of muscles should be trained. There are plenty of bodybuilders who hit the gym daily, but will tell you that they train most muscles a maximum of once a week, focusing on a high number of repetitions per session. Then there are those who recommend doing fewer repetitions more often, with six-day-a-week cycles not uncommon.
If you review some of the scientific literature concerning exercise frequency for optimal gains in muscle size, you’ll get a whole host of results — but unless other variables (like the amount of weight lifted and the number of repetitions) are standardized, it’s hard to compare one set of results to the next.
In an attempt to add clarity, a team of American and Australian researchers reviewed the results of several studies not only by the number of times an individual hit the weight room per week, but also by the number of repetitions performed per muscle group per week.
What they found is that when it comes to improving muscle size, frequency wasn’t an important indicator of success. High- and low-frequency training schedules resulted in similar increases in muscle size, provided the total number of reps performed over the course of the week was similar.
The studies included trained and untrained men and women and compared a variety of workout frequencies ranging from once to six times a week. Most of the data was based on two to three sets of eight to 12 reps per muscle group, which is considered a standard weight training protocol.
The conclusion that total volume is a more important measure of muscle gains than frequency held true whether training the smaller muscles of the upper body or the larger muscles of the lower body. It also held true whether the individuals were exercise novices or veterans.
The researchers compiled all the study subjects and results into a single bank of data, gathered from 800 individuals.
What’s also interesting about this study is that it suggests 48 hours between workouts may not be necessary for muscle growth, at least among weight room veterans.
That said, the researchers also pointed out that there’s a wide variety of individualized responses to training frequency and volume, so you shouldn’t be surprised if your results don’t match those reported in the studies.
But that’s not the most important take-home message — once again, science has proven that there’s a fair amount of wiggle room in traditional exercise prescriptions, be it cardio or weight training.
It’s also important to remember that variables such as volume, frequency and intensity need to be looked at as a whole, not a series of parts — adjustments to one can frequently be offset by adjustments to another. More volume and less frequency will likely offer similar results to less volume and more frequency.
So if you can only make it to the gym once or twice a week, you should consider longer workouts than someone who hits the gym more often.
There are a couple of caveats. Very specific exercise goals usually require very specific exercise routines. And some bodies respond better to more rest and some to less volume, so make sure you adjust accordingly. But for those whose goal is to build strength and add a bit of muscle, it looks like you can build your workout schedule around your preference of spreading the volume out over several days or cramming it into one or two workouts per week.
Research shows that for some weight room veterans, waiting at least 48 hours between workouts may not be necessary for muscle growth.