High Frequency Training Explained: Pros, Cons & Results

The first time I came across the idea of high frequency training was back in the mid 2000s, when I read an article by a guy called Chad Waterbury.

Waterbury’s basic idea was that the more often you train a muscle, the faster it’ll grow.

At the time, there wasn’t a great deal of research to compare high frequency training with more conventional workout routines.

That all changed with a study of competitive powerlifters dubbed the Norwegian Frequency Project, which showed superior gains in both muscle size and strength when the same amount of training was distributed across six versus three weekly workouts.

Since then, there have been multiple studies investigating the effects of high frequency training, or HFT for short, with some very interesting results.

Today, I want to take a closer look at what the research has to say on the subject of high frequency training and muscle growth, as well as outline a few practical ways you can incorporate it in your training program.

What is High Frequency Training? Who Should Use it?

For the purposes of this article, I’m defining high frequency training as any workout routine that involves stimulating a muscle group at least four times over a 7-day period.

It’s an approach that’s better suited to intermediate and advanced lifters, rather than beginners.

If you’re new to lifting weights, most research shows that your muscles will grow just as quickly whether your training is spread across two, three or four weekly workouts. 

In one study, a group of untrained beginners lifting weights once or three times a week for almost three months saw very similar gains in muscle size [1].

Strength gains were superior with the higher training frequency. But improvements in thigh circumference and muscle thickness were not significantly different between groups.

When scientists from Brazil’s University of São Paulo looked at the impact of training frequency in a group of untrained young men, they found no advantage to working a muscle more often than twice a week [2].

A follow-up study, again in untrained beginners, also shows no significant difference in muscle growth whether a muscle group was trained four versus twice a week [3].

What Are the Benefits of High Frequency Training?

One of the arguments in favor of high frequency training is that spreading the same amount of work over a greater number of training sessions will lead to a faster rate of muscle growth [4].

That is, if you normally do 12 sets for your chest in a single workout, simply dividing that work across three different training sessions – without doing anything else differently – will lead to more muscle being gained.

The idea is that there’s an upper limit on the amount of stimulation your muscles can respond to in any given workout. Going beyond that limit may simply prolong fatigue without producing a greater increase in muscle size.

Put differently, a relatively small number of sets is required to send the “make me bigger signal” to your muscles. Once that anabolic limit has been reached, additional sets are “wasted” in the sense that they contribute little to muscle growth. 

The extra work might create more muscle damage, which in turn extends your recovery time. But it doesn’t necessarily turn up the volume on the muscle-building signal sent to your muscles.

However, any extra muscle growth seen with a higher training frequency may have more to do with the fact that your muscles can do more work when your training is distributed across more workouts. 

That is, an increase in training frequency is useful only to the extent that it allows for a higher volume of training. 

For instance, let’s say that you train your legs once a week. You do four sets of squats, four sets on the leg press and four sets of leg extensions. 

By the time you’ve got to the leg extensions, your quads are going to be fried. You won’t be able to lift the same amount of weight, or do as many reps as you would have done had your legs been fresh.

But if you were to do those exercises on different days, fatigue from the previous exercises wouldn’t be a problem. You’d be stronger, fresher and able to lift a heavier weight, or do more reps with the same weight, which in turn generates a larger stimulus for growth.

High frequency training is also popular with some strength athletes as a means to improve their strength.

Strength is a skill that is developed through repetition. The idea is that more frequent training gives you the opportunity to practice that skill more often. 

And the more often you practice, the better you get.

Other than the potential for faster gains in size and strength, there are some other benefits associated with high frequency training.

For one, the lower workout volumes that go hand in hand with a higher training frequency will mean less post-exercise muscle soreness. This means you’re less likely to be hobbling around or limping down the stairs the day after training your legs.

It also gives you a lot more flexibility about how you schedule your training. Miss a workout, for example, and your whole week isn’t thrown out of whack. You can just push your training session back to the following day.

Does High Frequency Training Work?

The research on high frequency training and muscle growth is a bit of a mixed bag. Some trials show a large benefit, some show a small benefit, while others show no benefit at all.

Back in 2019, Brazilian researchers found that hitting a muscle group five times a week delivered significantly greater gains in muscle thickness compared to a more conventional split routine [5].

Subjects taking part in the study, all of whom had been lifting weights three days a week for at least 12 months, were assigned to one of two groups. 

The first group did a full-body workout every day, Monday through Friday, hitting each muscle group five times per week. The second group of lifters followed a more conventional program that involved working a muscle once or twice each week.

Both groups performed the same exercises, did the same number of sets, and lifted the same amount of weight (in terms of a percentage of their 1-rep max). Both groups, on average, also ate roughly the same amount of carbohydrate, protein and fat.

The result?

Lifters in the full-body group saw significantly greater gains in muscle thickness, measured using ultrasound, in both the biceps and quadriceps. 

The full-body group also gained nearly twice as much muscle in the triceps compared to the once-a-week group, although the difference wasn’t statistically significant.

However, HFT hasn’t produced a faster rate of muscle growth every time it’s been tested.

Researchers from the University of South Florida, for example, saw no significant difference in results when the squat, bench press and deadlift were performed six rather than three times a week [6].

However, the six-day group did see faster gains in lean body mass compared to the three-day group, although it wasn’t large enough to cross the statistically significant threshold.

Here’s how the researchers sum up their findings:

“Our data suggest that athletes will receive no further benefits from increasing training frequency without a subsequent increase in training volume and/or intensity. It is the opinion of the authors that coaches should increase training frequency when necessitated by an increase in training volume and intensity beyond the athlete’s current recovery capabilities.”

Brazilian scientists also report similar gains in muscle mass with a full-body workout performed five days a week versus hitting each muscle group 1-2 times per week [7]. 

But once again, while the difference between the groups wasn’t statistically different, the high frequency lifters did see faster gains in lean body mass.

With a longer study, the difference in body composition between the two groups may have been larger.

However, it’s also possible that hitting a muscle group five times per week would, over time, have become too much to recover from, leading to slower strength gains and smaller changes in lean muscle mass.

There are also trials where a higher frequency of training hasn’t had any kind of meaningful impact on muscle growth.

In one study, training a muscle either three or six times a week, under volume-equated conditions, led to similar gains in both muscle size and strength in resistance-trained men [8].

In fact, only the 3-day group saw significant gains in elbow flexor thickness.

In another, training a muscle four days a week was no more effective than twice a week when training volume was matched [9].

It’s also worth pointing out that not everyone responds to an increase in training frequency in the same way. 

While some people might benefit from hitting a muscle group more often, not everyone will see the same results. Most studies report group averages, but this can mask differences in results from one person to the next.

In one study, for example, roughly 3 out of 10 subjects put on more muscle when they followed a training routine that involved working a muscle five times per week [10]. 

Another 4 out of 10 saw faster results when they trained that same muscle 2-3 times each week. The others made similar progress irrespective of how often they trained.

Even after training volume was taken into account, some folks gained muscle faster on the higher training frequency [11].

So, what to make of it all?

Some trials show a benefit to higher training frequencies, while others don’t. 

Interestingly, none of the studies I’ve seen show that high frequency training is less effective than a more conventional training frequency of 2-3 times a week.

It’s one of those things I’d put in the “worth a try” category, especially if you’ve got a few years of serious training behind you and the gains are proving increasingly hard to come by.

How to Use High Frequency Training for Muscle Growth

One of my favorite use cases for high frequency training is to bring up a lagging body part.

In his early bodybuilding career, for example, Arnold Schwarzenegger’s calves were a real weak point. So much so that some of his early posing shots were done standing in water, with his calves hidden from view.

To rectify the situation, he started training his calves six days a week, for 30-45 minutes at a time. Two years later, Arnold’s calves had gone from an embarrassing weak point to one of his best body parts.

You can take a similar approach. Choose a muscle group you want to focus on, and simply work that muscle group 4-6 days a week.

Here’s something else you can try.

How Do You Structure a High-Frequency Workout Plan?

Let’s say you’re following a 4-day upper/lower split, and you want to give your biceps and triceps some extra attention.

You’d train your upper body as normal twice a week. Then, on both lower body days, you’d add some isolation work for your arms.

Here’s what it looks like:

• Monday: Upper Body
• Tuesday: Lower Body + Biceps/Triceps
• Wednesday: Off
• Thursday: Upper Body
• Friday: Lower Body + Biceps/Triceps
• Saturday: Off
• Sunday: Off

During your lower body workout, you might do a set of leg presses, squats or deadlifts, before resting for a minute or so. 

Then, you pick up a light dumbbell and crank out a set for your biceps or triceps.

Rinse and repeat until you’ve done 6-8 sets for your biceps and 6-8 sets for your triceps.

This allows you to do some extra specialization work for your arms without spending longer in the gym.

You could also choose a workout split that, by virtue of design, stimulates some muscles more frequently than others. 

For example, here’s what the 6-day Arnold Split looks like:

• Monday: Chest/Back
• Tuesday: Shoulders/Arms
• Wednesday: Legs
• Thursday: Chest/Back
• Friday: Shoulders/Arms
• Saturday: Legs
• Sunday: Off

Although the muscles in the chest, back and legs are trained twice a week, the shoulders and arms are being stimulated four times a week.

That is, you work your arms directly on shoulders and arms day. But they’re also getting some stimulation when you train your chest and back.

It’s the same story with the deltoids, which are trained twice a week on shoulders and arms day. However, they’re also involved when you train your chest and back.

You also have the option of training your whole body 4-5 times a week. A 5-day full-body workout plan might look like this:

• Monday: Full Body Workout
• Tuesday: Full Body Workout
• Wednesday: Off
• Thursday: Full Body Workout
• Friday: Full Body Workout
• Saturday: Full Body Workout
• Sunday: Off

If hypertrophy is your main goal, I recommend that you use different exercises, rather than stick with the same exercises from one workout to the next.

For instance, you might hit your quads with squats in one workout, leg presses in workout two and leg extensions in the third, before going back to squats again.

Doing so has a number of benefits:

For one, doing the same exercises all the time can get boring.

If you’re someone who likes a bit of variety, throwing some different exercises into the mix can make your workouts less of a drag, making it more likely you’ll stick to the program in the long run.

Training a muscle with several exercises is also more effective than training that same muscle with a single exercise. 

By using several exercises rather than just one, you target different regions of a muscle, leading to more complete development of a muscle group.

Doing the same exercises all the time, especially if you’re lifting heavy weights, can also take a big toll on your joints.

An increase in exercise variety can make it less likely that your knees, elbows, wrists or shoulders will flare up, helping to reduce the risk of a repetitive stress injury.