skip navigation

Mass. Hockey Spotlight: Slapshot Science

By Jamie MacDonald , 07/31/20, 1:45PM EDT


Newton's Alex Mohsen discovers the science in hockey

So many of the best ideas come from the simplest of questions.

What makes my slapshot go? And why can’t I measure it?

That’s the most distilled version of what Newton’s Alex Mohsen wondered before kicking off a school project that wound its way from his innovation lab classroom at Fessenden and through tens of thousands of lines of code collected by $50 worth of equipment, a backyard rink, some extra time at home this spring, and a willingness to put in long hours in researching an answer. The project combined a natural affinity for tech and computers, and the defenseman’s passion for the sport he has been playing since he was 5 while the family was living in Canada for a few years. 

The fruits of all this labor became the “Slapshot Analyzer,” a 6:13 video posted to YouTube that is all kinds of deep-dive into what makes his slapshot go. For a 13-year-old, it’s heady stuff, but it’s also wholly compelling in its data study. 

We’ve all seen video replays of the giant windups at the NHL All-Star Weekend’s Hardest Shot Competitions and the resulting MPH read-outs. We’ve all seen videos with stick flexes caught in stunning super slow-motion. 

But those elements aren’t readily available in a combined study of what’s actually happening as the actions and reactions slow the blade of a stick down while it strikes the ice, flexes and loads, then launches a puck and recoils.

Other sports have swing speeds and exit velocities and spin rates and all kinds of data. As far as Alex Mohsen knew, he had … Alex Mohsen.

“So, the first thing is, my slapshot varied a lot,” he says. “I wanted to see why. People said golf has things like a swing analyzer and I wonder whether we could do that for hockey. That’s pretty much the idea. And so we set out to answer that question.”

Mohsen’s data analysis found that stick flex played a vital role in the speed of his shot. The more stick flex, measured by flex time and flex angle, the faster the shot. 

As concluded in the YouTube video: 

More stick flex time -> bigger flex angle -> harder shot! 

Where it all began

“[Fesseden] has this incredible innovation lab, like a maker space, where they have 3-D printers and cables hanging from the ceiling,” says Alex’s father, Paulash. “It’s pretty awesome actually. And they all get some time in the lab or they can choose that lab as an elective. So that’s sort of what Alex chose.”

With a pandemic offering up even more time at home, he was able to continue the project in earnest in the family’s backyard rink. Add to this extra time a high-speed video recorder (also known these days a phone), an arduino, an accelerometer and an old laptop, along with, again, the determination to grind through the tedium of study, outtakes and scores of lines of code, and you have the stage set for reasoned results.

“It was a nice confluence of factors,” says Paulash, who, with an MBA from Harvard and an M.S. in chemical engineering from MIT, is no stranger to study himself. “The school has the set-up and what we have at home is the rink. He had all the hardware and could just go to the backyard and muck around for a little while. It worked out so nice. I thought it was a really cool project, but it was a lot of confluence of factors.”

"To be able to say, ‘I love this, so I’m going to learn more,’ ...It’s an amazing thing where you can actually find something that sparks your internal curiosity and allows you to learn and grow."

family affair

From Paulash’s perspective, watching his son growing up and taking on some of these rites of passage – developing the mental muscles to flex in a maker space at school or the gaining the physical strength to make the most of a flexed stick – has been as much a treat as anything.

“Are you kidding? It’s awesome,” he says. “I love it. I hope he does more of this stuff. Maybe there’s some ‘apple doesn’t fall far from the tree’ stuff going on, but you can definitely see some of the mechanical orientation. The relatively unique thing is that he has the interest in the sport also. Alex is a smart kid. You show him once and the rest he can get.”

Alex’s 9-year-old sister shares his passion for the game, too.

“She started earlier because, when we moved to Canada, she was 1 and on the ice by 2,” says Paulash. “She’s the one playing on the boys’ team and skating circles around her friends. It’s not all bad!” 

The most challenging aspect of the project

For one, all … that … data.

“What I had to do is go through almost 1,000 data points to find the exact time where my stick hit the ice and all that stuff just to see the graph,” Alex says. “And that was very hard and long, and it wasn’t very fun.”

In addition to going over the lines and lines of data after each swing of the stick, there were occasions one device or another wouldn’t work. Ah, technology. 

“There were a ton of times when either the video capture device did not correctly register the video or the data didn’t record on the arduino,” says Alex, who was born in New York City and fell in love with hockey after the family’s move north of the border. “One thing I did kind of dislike about it, though, is that there were so many wires. We had to run a wire from the stick into the computer, and that was sometimes very hard. If I tripped over it, I could almost cut it.”

what's next

Given another shot at it, Alex would like to go back into the world without wires.

“Going from wired to wireless would be a big, big improvement,” he says. “If I want to use it help me practice my slapshot, I’m definitely trying to create some sort of interface, almost like an app so it would be much easier to read the data. If there were some automation or code to help do that for us, that would be very helpful. And it would output much faster.”

the last word

“There are a couple things I’d say,” Paulash says. “Maybe three things. First, I think it’s truly amazing what you can do with technology at home these days. Second, this started out with Alex saying he wanted to fix a slap shot, so, to be able to actually put together a project that enables you to get to your goals is phenomenal. And, third, it’s great just finding areas that allow you to flourish in ways you can’t in school. To be able to say, ‘I love this, so I’m going to learn more,’ and you learn how to analyze data and ask questions. It’s an amazing thing where you can actually find something that sparks your internal curiosity and allows you to learn and grow. I think it’s terrific.”

For Alex’s part, it was a matter of wrapping together a couple of his passions: “I started with a little bit of coding, and I had originally done a lot of coding but I have since trailed off, and once I realized I could build it as an accelerometer, that’s where the project took off. It was something I knew a little bit about and something I love, which is hockey, and combining those. That’s probably how I got here.”