I write lots of product reviews for “geeky” tech stuff (like smart thermostats, automatic toilet flushers, surge protectors, etc.). But when I get a chance to review some tech that also involves one of my other interests (karate in this case), I’m all over it.

As a part-time karate instructor at Fairwood Martial Arts, one of the things we encourage students to focus on is punching and kicking harder. Traditionally, among the only indications of how hard someone’s striking or kicking is for a partner to hold a target and give them verbal feedback — which is highly relative and subjective. We also use board breaking to test striking power, but that’s as much mental as it is physical. Then, of course, there’s the tried and true “allow them to punch you and see how it feels” test. Although that last one gets real old, real quick.

Until recently, the only way to get a more objective measurement of how hard someone is punching or kicking is to take them to a sports lab (impractical and expensive unless you’re a professional MMA fighter) or to purchase the expensive equipment that such a sports lab might own. But the StrikeMeter®, made by Michigan-based Martial Arts Instruments LLC, seeks to change all that by putting a far more affordable solution in the palm of your hand… or more precicely, at the base of your Century Wavemaster® target.

What is the StrikeMeter?

In geeky terms, the StrikeMeter is a battery-powered accelerometer, housed in a plastic case, with a digital readout — designed to measure impact force by relying on the mathematical formula of Force = Mass x Acceleration. It’s mounted using Velcro at the base of a Century Wavemaster target (which are ubiquitous among martial arts schools) and displays a readout of how hard the target was punched or kicked by measuring how quickly the bag moved upon initial impact. The StrikeMeter is sold direct (and currently only available in the US due to some export restrictions because of its electronic components) for $199 online or by phone.

For a brief intro and to see it in action, check out StrikeMeter’s own video:

Origins of the StrikeMeter

When I asked the StrikeMeter’s co-inventor, 5th Degree Tae Kwon Do Master Kevin Hurlahe, his motivation for inventing the Strike Meter, he told me that the initial idea came in response to an unmet need in the martial arts training and teaching field. He’d tried other products, but thought they all had serious flaws. Most of them were hand-held (making them dangerous to use), had inconsistent and seemingly random scoring, or came across as cheap or gimmicky. As luck might have it, Master Kevin’s good friend and StrikeMeter partner, Dr. Dave Dilworth, was a PhD electrical engineer and instrumentation expert, who also happened to be interested in the idea. Since it’s inception, the StrikeMeter has been a two-family project, with six family contributors along the way, and in Master Kevin’s words, “a labor of love and a passion for the martial arts.”

Using the StrikeMeter and Understanding the Scoring System

I found installing the StrikeMeter on my own Century target in my basement gym exactly as easy as it appears in the video: peel the Velcro, put the Velcro on the target’s base, attach the StrikeMeter to the base of the bag, switch it on, wait a couple of seconds for calibration, then start kicking and punching. The unit came with very detailed instructions, which were easy to follow.

The StrikeMeter’s scoring units don’t translate directly to standard measurements of impact force such as PSI — and that’s a good thing. The fact that the StrikeMeter uses a proprietary measurement shows that they understand that there are too many variables involved (including how much water is in the base of the target, or the location of the StrikeMeter, or the angle of the strike, or the impact location on the target) to calculate something like PSI or Joules. By inventing their own measurement unit (which goes up to a maximum of 5,000 on the readout), they can still provide a reliable reading of whether your first kick was stronger than your third kick. In my testing there were no glitches, and I never felt like the StrikeMeter gypped me on a score. My first two or three hits were always my best, then as I got more tired, my score trended downward. According to the manufacturer’s laboratory testing, a score of 400 is roughly equivalent to 30 Joules, which is the amount of force required to break a standard 1″ pine board. A score of 700 is about two boards, and a score of 1000 is three boards.

For a more in-depth look at the scoring system, the geekier among my readers will enjoy this blurb from an email conversation between myself and StrikeMeter co-inventor, Kevin Hurlahe:

The raw score is similar to G-force. The raw score that determines force is not very rewarding to users for a couple of reasons. First, the range between the units of measurement are too narrow to provide adequate feedback to the user. There’s not enough differentiation between the units to keep it interesting, or to determine if you are making progress on your techniques. Also, our proprietary scoring system was designed to “reward” the elements of an effective martial arts strike impact (combining speed, mass, follow through, balance, etc.). The more “damaging” the strike – the higher the score. For example, you can push the bag with a lot of force and strength – tilting it way off of its axis (representing a lot of muscle strength) but it would result in a relatively low score. You could also “swat” at the bag with speed, such as with a lightening fast backhand strike, but you would also get a relatively low score. However, when you combine the speed and the strength of a proper martial arts strike, you are rewarded with a much higher score. Imagine a full contact sparring match. A slow kick with a lot of mass and muscle strength behind it would be ineffective because it wouldn’t hit the opponent. A quick strike without proper follow through or leverage might hit the opponent but would not do any damage. A student of the martial arts must learn to develop strikes that are quick enough to hit the target, and powerful enough to cause damage. You and I take this for granted, but beginners don’t always understand this (especially children). For example, if you train on traditional hanging bags, you’ve seen that children and beginners kick the bag in a “pushing motion” so they can get the bag to swing (falsely believing that this represents a “strong” kick). You and I know that the most powerful kickers make the bag “jump,” not swing. StrikeMeter rewards this type of kick with a higher score. It creates a positive feedback loop for the student’s training progress.

There are other advantages to the proprietary 0 to 5000 scoring range. We wanted a measurement device that could be used by all ages equally. We have 4 year olds that are delighted when they get a score of 100. We have adults who are ecstatic when they score in the 3000 to 4000 range. The scoring system is not linear – making it more versatile for the different size and strength of users.

As I continued to play with the Strike Meter in my home gym, and enjoyed trying out different punches and kicks to see what kind of numbers I could hit. But the real fun started when I took it to our dojo to let others try it out… because that’s when competitive human nature kicked in. 🙂

Speaking of using the StrikeMeter in multiple locations, it’s very easy to do by simply buying a little bit more Velcro from any local hardware store and applying the “male” side of the Velcro to the base of a different bag. Once the Velcro is in place, attaching the StrikeMeter literally takes only seconds. I see that as huge benefit vs more complex measurement systems.

I wish I’d taken my video camera with me the first time I took it to the dojo, because I would have loved getting footage of our kids’ classes. The kids loved lining up, taking a run at the target, then hitting or kicking it as hard as they could. As they saw their result, they’d yell out the number and ran to the back of the line. Each successive student would try to beat their friend’s score, and also beat their own. So in the absence of my footage, I’ll share this video from the StrikeMeter website of Master Kevin’s kids class:

Back in my home dojo, the adults (including my fellow instructors) didn’t bother lining up politely like the kids. We just hovered near the target taking turns… claiming to only care about improving our own score, though we all knew we were trying to win.

A couple days later, I remembered to bring my camera to the dojo… but when I took the StrikeMeter out of my gym bag and switched it on, it was dead. The switch is located on top of the unit, and something in my bag must have bumped the switch and turned it on, draining the battery (an auto-off feature after a few minutes of non-use would be a nice feature to see in the next version). Unfortunately, we don’t keep 9 volt batteries at the dojo, so I had to wait for another day to play with it again.

Going for 5000

The following week I co-taught an evening class with my buddy Sensei Axel, who is literally the strongest person I know. I hadn’t been able to make the StrikeMeter read 5000 in my testing, and figured that if anyone could do it, maybe he could. We were busy teaching class that night, so we couldn’t film until after karate class was over… which is when the evening kickboxing class starts! So please excuse the techno workout music in the background of this short video of Sensei Axel and I trying to make the StrikeMeter hit its max reading of 5000. And thanks to instructor Sensei Que Phong for letting us pull her out of kickboxing class it give it a try, too!

We didn’t ever quite hit 5000, but Axel got pretty darn close, and I’m not giving up just yet. But this proved that having an easy-to-use device that gives you instant feedback is a big motivation to dig deeper, improve your technique, and basically just… hit… harder!

Benefits of the StrikeMeter

Anyone who enjoys martial arts, but especially those who teach kids, will immediately see the obvious benefits the StrikeMeter. A student’s first punch or kick becomes a baseline, allowing the instructor to coach the student on proper techniques (chambering, foot position, speed, follow through) and help them achieve higher scores and reinforce the importance of improved technique.

I’ve always been a believer in metrics of any sort, and have always found it true that when performance is measured, performance improves. The StrikeMeter helps students improve more quickly, and adds a gamification element to their workout — to the point that they’ll often forget it’s a workout.

Limitations

As with any technology, the StrikeMeter has some limitations… though I don’t consider any of them “deal-killers.” But this wouldn’t be a fair review if I didn’t spend at least a few brain-cycles on how the StrikeMeter could be improved.

1. I’ve already addressed the fact that I’d love to see the next version get an auto-off feature.
2. The previous reading disappears very quickly from the screen, almost too quickly… although I understand why they designed it that way. It would get pretty annoying standing around waiting “Go” message when you’re ready to strike again. So another suggestion for version 2 would be a button to recall the last reading — and while I’m tossing out ideas, maybe even the ability to use that button to cycle through and also see the max reading of the session (which could be reset with a different button or by simply switching the device off and on).
3. Users of the StrikeMeter also need to make sure that they are kicking or punching the target directly above the unit — otherwise the acceleration won’t be measured properly and you’ll get inaccurate readings. That’s not so much a limitation as it is a recommendation to make sure you’re using the unit properly.
4. And if I’m really stretching, the only other limitation I can think of is that the unit’s not available (yet?) on Amazon. I love buying stuff on Amazon.

Bottom Line

After putting it through its paces, I’m happy to report that the StrikeMeter does exactly what its makers claim it does: it’s an easy to install, easy to use use, self-contained device that provides a fun and reliable method for martial artists (and especially martial arts instructors) to measure the impact force of techniques.

At $199, I think it’s a bargain. It’s only $60 more than a Century Wavemaster target, which most martial arts schools purchase regularly — and it dramatically improves the functionality of any target to which it’s attached. You won’t find any other tool that can provide this type of feedback for anything close to that price (trust me… I looked). It’s well built, right here in the USA, and the manufacturer told me that they’ve never had a complaint or return of any of their units. I had a hard time believing that before my review unit arrived, but after using it myself, I totally believe it now.

Bottom line: if you’re a martial artist who takes your training seriously, has at least one Century Wavemaster in your basement, and likes gadgets (why does that sound familiar?), you won’t regret buying yourself a StrikeMeter. But the true target (pun intended) market for this device is martial arts instructors. And for them, I have zero doubt that this device will quickly pay for itself. In the competitive martial arts school market, having one or two StrikeMeters in your dojo can be a differentiator that helps you attract and retain students.

For more information or to order, visit http://www.strikemeter.com/