Will martial arts get you fit, and what it will not do

The short version: yes, and not in the way most people assume. Martial arts training reliably builds your heart and lung fitness and your muscular endurance. It does not make you strong, and the evidence that it changes your body shape on its own is thin. If you want those two things, keep training and add a small amount of lifting.

The most useful piece of evidence on this is a study that tested 935 adult practitioners across jiu-jitsu, judo, karate, kung fu and taekwondo and compared them against population norms. The results split cleanly. Aerobic capacity came out above average. Muscular endurance came out above average. Flexibility came out average. And maximum strength came out below average, across every single style.

That split is the answer to the question, and it is more useful than a yes or a no. The training builds an engine. It does not build a chassis.

What the training actually builds

The engine part is real and it is not a small thing.

Rounds are intermittent, hard, and repeated with short recovery, which is close to the textbook description of interval training, and it shows up in the testing. Aerobic capacity above population average across five different arts is a meaningful result, because these were ordinary practitioners rather than competitors on a strength and conditioning programme.

Muscular endurance came out above average too, which matches what the training feels like. Holding a position under someone's weight, throwing hundreds of kicks, gripping for five minutes at a time. That is endurance work whether or not anyone calls it that.

So if the question is whether you will be fitter after six months of twice a week, the honest answer is yes, noticeably, in the sense of being less out of breath walking up a hill.

What catches people out is that fitness does not travel in either direction as well as they expect. Runners arrive in good cardiovascular shape and still gas out in their first rounds, because gripping, bracing and carrying someone else's weight is a different demand from moving your own body forward. And the reverse holds: months of hard rounds will not make you good at a steady five kilometres. If you want both, you have to do both, and neither one is evidence that you are unfit.

What it does not build

Here is the part nobody selling classes will tell you.

In the same testing, maximum strength came out below average for every art, with the authors singling it out alongside body composition as the only measures not above average, and recommending instructors do something about it. That is a striking result. These are people training a physical sport several times a week, testing worse than the general population on strength.

The reason is mechanical rather than mysterious. Getting stronger requires loading a movement and then loading it slightly more, repeatedly, over months. You cannot do that in a sparring round, because the resistance is another person who decides how hard they go, and it changes every time. Martial arts asks a lot of your body without ever asking the same thing twice in a measurable way, and that is exactly the thing strength adaptation needs.

One caveat worth stating: that study tested men only. It is the largest picture available and it is not the whole population.

It is not identical across the arts

The same testing compared the five styles against each other, and the differences are worth knowing if you are picking partly on fitness.

Two caveats on reading that. These are comparisons between groups in one study rather than a league table of the arts, and the body composition results put karate, jiu-jitsu and judo practitioners between overweight and normal ranges while kung fu and taekwondo sat in normal, which probably says as much about who each art attracts as about what it does to them.

Body composition is the thing people expect most and get least

Most people asking whether martial arts will get them fit are partly asking whether it will change how they look. The evidence there is much weaker than the confident answers online suggest.

A review of six randomised trials covering 258 overweight or obese adults looked at exactly this. Body mass index moved by −1.34 units and the result was not statistically significant. Body fat percentage barely moved at all. Waist circumference did not improve. The authors concluded plainly that the available studies do not allow them to say whether martial arts is effective for these outcomes.

Two things about that before anyone over-reads it in either direction. Four of the six trials studied tai chi, which is not what most people picture when they imagine a martial arts workout, so this is not a test of hard sparring. And the review criticises its own evidence base as small, short and poorly designed. The honest summary is not that martial arts fails to change body composition. It is that nobody has properly demonstrated that it does, which is a very different thing from the certainty you will find on most pages answering this question.

What is not in dispute is that body composition responds far more to what you eat than to which class you attend.

What to add, if you want the rest

None of this is an argument against training. It is an argument for two short sessions a week of something dull alongside it.

Squat, hinge, push, pull, carry. Twice a week, forty minutes, heavy enough to be hard for five or six repetitions. That is enough to move you from below average to comfortably above it, and it will make you better on the mat as well, because strength is useful everywhere even though the mat will not build it for you.

The objection everybody raises first is recovery: if two mat sessions already leave you sore, where does lifting fit. The answer is that two sets of five heavy squats is far less fatiguing than a five minute round, and it is the volume of lifting rather than the weight that wrecks people. Keep the sessions short, keep the repetitions low, and put them on non-training days or in the morning. If you are constantly too wrecked to lift at all, that is usually a sign the mat sessions are too hard rather than too many.

The scheduling objection is the other one, and it is the same arithmetic we went through in training around a full-time job. Two mat sessions plus two short lifting sessions is four commitments a week, which is a lot. If something has to give, keep the mat sessions. The training is the thing you enjoy and the lifting is the supplement, not the other way round.

If you are starting later, the strength side matters more rather than less, for reasons we went into in the best martial art to start after 40.

The thing it genuinely beats the gym at

Every page arguing that martial arts is superior to the gym is written by somebody who runs a martial arts gym, so it is worth saying what the real advantage is, because there is one and it is not conditioning.

People turn up. A martial art has training partners who notice when you are missing, a coach who knows your name, a skill that takes years and visibly improves, and a reason to be somewhere at seven o'clock on a Tuesday that has nothing to do with willpower. Almost nobody sustains a solo gym programme for five years. Plenty of people train a martial art for twenty.

Over a year, the training you actually do beats the better programme you quietly stopped doing in February. That is not a small point, it is most of the point. We have not gone looking for evidence on adherence rates specifically, so treat that as an argument rather than a finding, but it is the advantage worth weighing and it is not the one the gyms lead with.

If you have not started yet, our directory lists gyms with their published timetables where they have one, which is the quickest way to find the two sessions a week this all rests on.

This post summarises published research and is not medical or training advice.