Why Slap When Breaking a Fall?

Learning how to fall safely is an important part of participation in martial arts and many competitive sports. For a throwing style like Judo, mastering the ukemi arts is essential for anyone who wants to train regularly. It's also crucial for sports like Muay Thai, where landing badly after a leg sweep can result in serious injuries. [1] The serious injuries I've seen in Muay Thai classes -- things that caused someone to have to put their training on hold to recuperate -- were a result of their body hitting the ground after slipping or being swept, not a result of being hit by another student.

There are many schools and web sites that explain proper falling technique. However, very few of them explain why we do the things we do. If you ask, you might be told that slapping "distributes the impact", with no further details provided. To be fair, no further details are strictly required: if you do as instructed, you will land correctly.

This article is an attempt to explain the "why" in some detail, primarily for the benefit of advanced students and instructors who aren't satisifed with the one-line answer. My motivation for writing this is twofold: I believe advanced students benefit from a deeper understanding, and I have seen cases where instructors who didn't fully understand an art encouraged risky variants because they believed their modifications made the technique better.

I'm going to assume you're already familiar with proper technique, and will not attempt to explain it here. Learning the basics by reading web pages is a terrible idea. If you don't know how to fall, find an instructor who can teach you in person.

Anatomy of a Breakfall

I'll start by breaking down a side fall. Imagine you're the uke for a simple right-side hip throw, and are about to land on your left side. You need to do several things.

  1. You need the right general body position. This is what I call the "obvious part", because a casual observer can see if it's correct at a glance. And if you don't get this right, the finer points won't matter much.
  2. Humans want to catch themselves with their arms when they fall. This is an instinct that developed because a broken wrist heals more quickly than a broken head. Teaching people not to do something is easier when you replace the bad action with a good action. In this case, it's useful to tell the student to do something specific with the left arm.
  3. You need internal rotation of the left shoulder. If you're standing up with your arm loosely at your side, internal rotation means turning your arm so the back of your hand is touching your thigh and your elbow is pointing forward. If you don't do this, you'll land on the outside of your shoulder instead of the posterior deltoid (back of the shoulder). If you poke at the outside of your shoulder you'll feel a bone, called the acromion, that sits on top of the shoulder joint (it's part of your scapula). Landing on that can be very painful [2] I vividly recall doing this. I only recall doing it once, because after that I paid more attention to my shoulder position. and lead to injury: according to the Mayo Clinic site, "The most common cause of a separated shoulder is a blow to the point of your shoulder or a fall directly on your shoulder."
  4. Rotating the acromion out of the way isn't enough. You need to rotate the left arm far enough that the left elbow isn't going to hit. Sometimes beginners will chop the ground with the edge of their hand instead of slapping with the palm. In this position the point of the elbow is likely to smack into the ground, which can cause olecranon bursitis, also known as "a big puffy lump on the elbow". [3] One time I did this and the bump stuck around for weeks. I think it was getting aggravated by impact even when I landed properly.
  5. You need to tense the muscles that are taking the impact, notably the latissimus dorsi. Your lats cover your mid-back and the sides of your rib cage, and are a prime mover in exercises like pull-ups and rows. At the moment of impact you want the muscle on the left side of your body to be tense, so that it provides maximum cushioning for the ribs.
  6. You also need to tense your transversus abdominis and lumbar multifidus. You probably know where your abs are; the multifidus is on the other side, stabilizing your spinal column. [4] I hadn't heard of the multifidus either until I spent a month in physical therapy for low back pain. If you draw your belly button toward your spine, you'll activate both. Doing so is important because landing on your side causes a shearing force on your vertebrae that can lead to low back problems.
  7. Exhale forcefully. A hard impact can be jarring on your diaphragm, which is the muscle that opens your lungs when you inhale. If you're mid-exhale at the moment of impact, you're less likely to get the wind knocked out of you.
  8. You need to relax immediately after impact. Laying on the ground clenched up is not a good plan, whether you're in a competitive sport or a self-defense scenario. You can't move quickly and fluidly if you're not relaxed.
  9. All muscles not actively participating in the breakfall should be relaxed throughout the fall. It's harder to control your fall if you're doing your best impression of a brick.

Great, got all that? Excellent! Now that you've mastered the side fall, let's talk through the finer points of a back fall. No need to repeat the information from the previous section, so this will go faster.

  1. First and obvious: tuck your chin to your chest. So long as you do this, you can get flipped upside-down and fall head first and come away fine. [5] Probably best if you just trust me on this one.
  2. Pull your scapulae (shoulder blades) together. Try standing with your upper back pressed against a wall and your shoulders hunched forward. You'll feel the inside edges of the shoulder blades rubbing against the wall. If you land on a hard surface in this position, the impact will be received by the narrow surfaces of the bone. If you curl up even more you'll feel your vertebrae hit the wall. Pulling your shoulder blades together protects your spine, and positions the bones to form a flat surface.
  3. Tighten your trapezius ("traps"). This is a diamond-shaped muscle on your back that goes from the back of your head to your low back, and extends out to your shoulders. When you fall on your upper back, this is what you're landing on, so you want it to be tense at the moment of impact.
  4. As in the side fall, there is a natural tendency to reach back and stop the fall with your arms. This can easily cause broken wrists and smashed elbows. [6] I once saw a young woman with a fully dislocated wrist (looked like a stair step). She had slipped and fallen during a fitness class. Focusing on doing something else with the arms reduces this tendency.
  5. You need to keep your elbows from hitting the ground. You can try to adopt a position with your arms in front, like the bottom of a push-up, but it's awkward to do and places the weight of your arms over your shoulders when you hit. Better to have your arms out to the side. As in the side fall, this requires that you internally rotate your shoulders to protect your elbows.
  6. Tighten your transversus abdominis and lumbar multifidus. As in the side fall, keeping your core muscles tight will help avoid low back issues.
  7. Exhale forcefully. This is arguably more important for back falls than side falls. [7] If you've ever landed flat, hitting the floor with your mid-back, you'll probably understand the argument in favor.
  8. Relax after impact. Keep all other muscles relaxed throughout the motion.

Easy, right? If you've spent any amount of time teaching martial arts, you know that asking a student to perform a long list of actions involving the activation of specific muscles is doomed to failure.

A Simpler Way

You could spend ten minutes explaining all this stuff, but your students will likely be confused and move on to some other hobby. Fortunately, there's an easier way. After describing the "obvious" parts of the fall position, you tell the student to slap the mat and kiai at the moment of impact.

Slapping the mat:

A proper kiai / k'ihap:

Slapping the mat does help you distribute the impact of the fall. Contrary to popular belief, [9] Like many topics in martial arts, misinformation is most commonly distributed by people who have enough training to feel comfortable sharing an opinion, but not enough experience to have a deep understanding of the subject. You can find examples on this quora page and this quora page. The responses on this reddit page are mostly correct, while this reddit page started badly but got better over time. it doesn't accomplish this by absorbing a massive amount of energy with your hands and forearms. It does it by ensuring that your body is in the proper position, with the proper muscles tensed, at the proper time.

You absolutely do not need to slap or kiai. You just need to do all of the things listed above, at the right time and in the proper way. Slapping the ground and shouting just happens to be the easiest way to go about it.


I didn't go into face falls, but the same concepts apply. The instinctive response to falling forward is to extend the arms, which can easily lead to a broken wrist. [10] A couple of years ago my mother stumbled while walking down the street, fell, and broke her wrist. Six weeks later the brace came off. Two weeks after that she broke it again the same way. Learning to fall while your body is young enough to recover quickly from mistakes is important. Some people, upon being told to land on their forearms, do so with their elbows positioned directly below their shoulders. This puts the brunt of the impact on the elbows, and delivers a hard shock to the shoulder joint. Slapping with the hands and forearms helps keep the elbows wide, allowing the arms to act like a spring instead of a frame.

When teaching fall breaks to new students, it's usually best to start close to the ground. For backfalls that means beginning with situps with a slap, then doing sit-down-roll-back-and-slap from standing, then taking falls from a low squat (which can get ugly if they have poor flexibility in their hamstrings). For face falls, start from the knees, then advance to standing with legs kicked wide apart. Side falls begin with rolling side-to-side to get the position, then kicking a leg sideways while squatting, then while standing. All of this is done before any "real" falls. This progression is especially important when teaching kids, because they have a harder time suppressing instinctive behavior and will tend to land on their elbows.

There are other "teaching shortcuts" that are worth using. For example, the most effective way to teach people to tuck their chin when learning backfalls is to tell them to look at their own bellybutton, or out past their knees. If you say, "keep your chin tight to your chest", people will clench all of their neck muscles, front and back. Because the muscles that raise the chin are engaged as well as the muscles that lower the chin, their ability to keep their head in place is weakened. If you tell them to keep looking at a low point, they will automatically tighten only the muscles in front. [11] If somebody is having trouble with head position during basic backfall drills from a seated position (i.e. doing situps with a slap), I'll hold my fist level with their knees, and briefly extend a few fingers right as their shoulders hit the mat. If they can't tell me how many fingers I held out, they can't argue that they had their chin tucked.

I don't think there's a need to explain any of this to beginning students. Their time is better spent practicing than receiving a lecture. If somebody indicates a deeper interest by catching you after class and asking "why", then it's worth explaining the details.

Copyright 2019 by Andy McFadden