How many legs days a week should you do if you want them to grow? Is one leg day a week enough? Is three times a week too much? Let’s find out.
If you want a short and simple answer to the question, it’s twice a week. There are cases where one leg day per week will do the job. But for most people most of the time, two leg days a week is the sweet spot for muscle growth.
However, the long answer is more nuanced, so let’s take a closer look at what the science has to say about training frequency and muscle growth.
What is a Leg Day?
By leg day, I’m talking about a workout that targets the muscles in your lower body, in particular your quadriceps and hamstrings, although the same principles apply to other muscles in your lower body like the glutes and calves.
Let’s say you’re training your legs twice a week, doing something like this:
In this case, you could argue that you’re training your legs twice a week.
However, the hamstrings and quadriceps are being trained only once a week.
That is, workout one is targeting the hamstrings, while workout two hits the quads.
Technically, you are training your legs twice a week. But the quadriceps are only being trained only once a week, and so are the hamstrings.
When I talk about leg day, I’m referring to a training session that works both the quadriceps and hamstrings, rather than one or the other.
How Many Hard Sets Are You Doing?
No discussion of training frequency is complete without a mention of training volume, which I’m defining as the number of hard sets you do for a given muscle group over the course of a week.
If you’re training your legs twice a week, but only doing 4-6 sets for each muscle group over the course of that week, the gains will likely come more slowly compared to doing 10 sets just once a week.
In this particular example, one leg day a week is going to give you faster results than two. But that’s only because of the increase in training volume, rather than because you’re training your legs more often.
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That is, the muscle-building benefits of two leg days a week were driven more by changes in volume rather than frequency.
Is One Leg Day a Week Enough?
You can still hit your legs once a week and make progress. Training them twice a week may well give you faster results, but one leg day a week is still enough to make your quads and hamstrings bigger.
There was an interesting study published in the Journal of Strength and Conditioning Research, where researchers got two groups of trained men to lift weights for two months .
Both groups did the squat and leg extension for their quads, for the same number of weekly sets. The only difference was in how often each muscle group was trained.
The first group hit their legs once a week, while group two trained their legs twice a week.
Statistically speaking there was no significant difference in results between the two groups. Whether the legs were trained once or twice a week, the amount of muscle growth was very similar.
- Group 1 + 9.2 %
- Group 2 + 9.6 %
- Group 1 + 9.2 %
- Group 2 + 10.9 %
When the researchers looked at total volume load (sets x reps x weight) for the duration of the study, subjects training their legs twice a week ended up doing the most work.
Over a longer period of time, the increase in volume load with the higher training frequency may well lead to faster gains in size.
To quote the researchers directly:
“It is plausible to hypothesize that this greater [volume load] achieved through a high frequency protocol if executed for a longer time frame (more than 8 weeks) may possibly culminate in a significantly greater increase in strength and hypertrophy compared with a single-session per muscle group.”
With that said, the group hitting their legs just once a week still made gains. Over a period of months and years, the gains may come more slowly compared to twice a week.
But if you’re willing to accept that your legs won’t grow as fast, one leg day a week is still a viable option.
3 vs 2 Leg Days Per Week
Will doing legs 3 times a week make your legs bigger compared to twice a week?
The answer to that question depends a lot on what your weekly training volume looks like.
If you do 6 sets twice a week, or 4 sets three times a week, you’re probably not going to see much of a difference in terms of muscle growth.
That’s because the total number of sets you’re doing over the course of the week is the same. As a result, you’re likely to see very similar gains.
But in practical terms, more frequent training will typically allow for an increase in volume.
That is, adding a third training day means you’re able to do more work for your legs. And the extra work itself may lead to faster gains. But that was because of the increase in volume, rather than the increase in frequency.
In fact, many studies report similar increases in muscle size in volume-equated programs irrespective of whether a muscle group is trained 1, 2, 3, or 4+ days per week .
For example, Brazilian researchers looked at the effect of two different training frequencies on gains in size and strength in two groups of untrained young men .
- Group one trained their legs twice a week.
- Group two trained their legs four times a week.
The total number of weekly sets was the same in both groups.
At the end of the study, there was no significant difference in terms of size or strength gains between the two groups.
Whether the legs were trained twice a week or four times a week, the end result was much the same.
Similar results were seen in a group of trained men who hit each muscle group two or three times a week .
Changes in muscle thickness of vastus lateralis, one of the four muscles that make up the quadriceps, were not statistically different between the two groups.
It was the same story with rectus femoris, which runs down the front of your thigh. Gains in muscle thickness were not statistically different whether the legs were trained twice or three times a week.
In fact, the twice a week group did see faster gains, but those gains weren’t large enough to cross the statistically significant threshold.
To quote the study authors directly:
“It should be noted that small, but potentially meaningful differences were observed in favor of training muscles two versus three days per week for every hypertrophy outcome measure studied. These findings suggest a potential hypertrophic benefit to the lower training frequency. It remains possible that small, but potentially meaningful improvements may be elicited by employing a training frequency of twice per week as compared to training three times per week.”
If you’re an advanced lifter doing more than 10-12 sets for your quads and hamstrings each week, then distributing that work across two leg days a week is likely going to give you better results than one.
But if you’re doing less than 10 sets for your quads and hamstrings, chances are you’ll make similar progress irrespective of how often your legs are trained.
Individual Differences and Training Frequency
There are also individual differences from person to person, and no two people respond to the same training program in the same exact way.
In one study that looked at training frequency and muscle growth, around 30 percent of the participants saw faster size gains when a muscle was trained five days per week .
In contrast, forty percent registered faster progress with a training frequency of 2-3 days a week. The remaining subjects made similar progress irrespective of how often each muscle group was trained.
From a physiological point of view, a training program that’s optimal for one person might not be optimal for someone else, so you will need to experiment and find an approach that works best for you.
You also need to factor in your own preferences and goals.
How important is it to have bigger legs? Some people aren’t that bothered. They want a bigger chest, back, arms or shoulders, but they’re content to see a slower rate of growth in their legs.
Do you hate leg days? If the thought of devoting an entire training session to your lower body (as you would do with a push/pull/legs routine or upper/lower split) fills you with dread, there’s no rule that says you need a separate leg day at all.
For example, you could follow a push/pull workout plan, where you do some work for your quads and hamstrings every time you train.
That is, the push day workouts involve some exercises that focus on your quads, like the squat and leg press, while the pull day workouts will include some work for your hamstrings, like the leg curl and Romanian deadlift.
Are you trying to gain or maintain? Maybe your thighs are as big as you want them to be, and you don’t want to make them any bigger.
Maintaining muscle mass takes a lot less work than gaining it in the first place, so you could probably get away with one short leg day a week, just to keep things ticking over.
To sum up, if you want your legs to grow, training them twice a week is your best bet.
However, there’s no universally correct training frequency that works equally well for everyone, nor are there rigid guidelines that determine exactly how many leg days you should do each week.
You can still make gains with one, three or even four leg days a week, just as long as your training program is set up properly, and you train hard, eat right and stay consistent.
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