RFID in the NHL – Part 3Analysis

RFID in the NHL – Part 3

Here Comes The Boom


Play stopping, puck removing, momentum shifting, bone breaking ….. Hits. Not everyone, but a lot of people love the big hits. Don Cherry has made an absolute fortune on his yearly VHS than DVD and now Blu-Ray, Rock em Sock em videos. One of the most massive hits I have ever watched in real time and not in a highlight reel was when Darcy Tucker annihilated poor Sami Kapanen as he crossed the blueline in an early 2000’s playoff series. Kapanen was hit so hard that he had to swim off the ice. I remember reading reports that he had not realised that the Philadelphia Flyers had even beaten the Leafs to win the playoff series.

I decided to take a little bit of a different approach with Part 3 in my RFID Series than I had originally intended. I decided to get some fun out of what RFID could lead us to knowing. Imagine a possible “Hit Score” come up during a replay of a bone crusher. We all remember high school math and physics right? I bet some of you will remember calculating total energy at the time of collisions in Grade 12 and OAC Physics. I may have completely dated myself.

Previously I have shown “the math” behind my madness, and once again, I will do so. I did promise in my last piece that I would not show anymore math, but I think hits are justifiable reason too. I am as well, not sorry, for bringing back the math. Hits are fun, I love a couple good bone crushers a game.

A Quick Scenario and Example Calculations

A winger(1) is travelling up the ice with the puck, at a speed of 30 kph(8.3m/s). As he approached the oppositions blue line (with his head down < — IDIOT), he was hit by a defenseman(2) travelling 25kph(6.94 m/s) in the opposite direction. Let’s assume the winger weighs in at 200lbs(91kg) and the defenseman weighs in at 250lbs(113kg).

All of the information above will be easily attained with the use of RFID location data. Previously I have shown how speed can be calculated using location over time and player weights are obviously known. With the data above Initial Momentum and Initial Kinetic Energy can be calculated.

For the following examples I will be assuming that the hit(collision) is linear and is inelastic. One may ask why I decided on an inelastic collision? Well, I suggest reading “Physics of Hockey” by Alain Haché, a professor of physics at Canada’s University of Moncton. A lot of cool information is available in there. I am only about ½ way through but so far it is really interesting.

Initial Momentum and Initial Kinetic Energy

Initial momentum could be used to mathematically isolate what player took the brunt of the hit. To calculate this, the speed of the player must become a vector and will now become a velocity(direction). I have chosen to give the defenceman the negative(oppposing direction) velocity only because he is the one opposing puck travel. How this is decided in the real world is up to people far superior to myself.

Initial Momentum in 3 steps

  1. p = m1v1 + m2v2
  2. p = (91)(8.3) + (113)(-6.94)
  3. p = – 28.92 kg m/s

Since the calculated number is negative this could represent that the winger was overcome by the defenseman representing taking the “brunt” of the hit. Even though the winger was traveling along the ice surface faster than the defencemen, the defensemens weight(mass) was larger and therefore giving him the advantage in this scenario.

Initial Kinetic Energy in 3 Steps

  1. KE = 1/2 m1v12 + 1/2 m2v22
  2. KE = (.5)(91)(8.3)2 + (.5)(113)(-6.94)2
  3. KE = 5855.7384 Joules

This is how much energy in Joules was present at the time of the collision. The collision could have had more energy present, because the “hitter” could have increased his overall velocity at point of impact relative to the ice surface by leaning forward at the last second or possibly raising his forearms towards the body of the winger. But for the purpose of this piece I decided to keep it really simple. If you are not familiar with a Joule, it is ok, I got your back.

A Joule

A Joule has many meanings. For the purpose of this piece I will explain it in an electrical manner, mostly because I am an Industrial Electrician by trade. I also feel using a home device such as a TV or a radio may help make it easier to understand.

One definition of a Joule electrically is: 1 Joule is equal to 1 watt used over 1 second. J=Ws.

An average 42” LED TV uses around 80 watts of power. In the above on ice collision the Initial Kinetic Energy was 5855.7384 Joules. If we use an electrical definition of a Joule, the above collision could potentially power the 42” LED TV for 73.2 seconds or 1 min 13 seconds.


  1. 5855.7384 = 80(s)
  2. 5855.7384 / 80 = s
  3. s=73.2 seconds

Lets do that one more time using that clock radio next to your bed. The clock radio next to my bed uses only 7 watts of power.


  1. 5855.7384 = 7(s)
  2. 5855.7384 / 7 = s
  3. s=836.53 seconds

The above representation of time means that the NHL hit in the above scenario could potentially power my clock radio for 13 min and 54 seconds. That is longer than the average snooze button timer. There is a lot of power/energy behind the calculated hit above.

The above scenario and quantification is a very simple example, it was a  one dimensional collision. There are many more types of hits than straight on linear collisions in the NHL. Many different incidents will be harder to measure but can be done. Here is an example of how to calculate a collision on two dimensions.

RFID won’t be an overnight success. Like any new machine processes being developed there is always going to be a commissioning and debugging period, but they have to start somewhere.

Hit Scoring

I had previously mentioned the potential to create a “Hit Score”. By calculating the Initial Momentum of a hit, a broadcast booth computer can assume instantaneously who “won” the hit and easily give the hit a “score”. How a broadcast may represent something like this, I do not know. Visually speaking, the player laying on his ass is usually not going to be the winner of a hit, but for the back end instantaneous decision purpose, a broadcast may not have time to manually decide on a winner prior to a reply and may have to rely on something like Initial Momentum. I am no marketing wizard, but I could see potential bonus score increases for things like a lost glove, a lost bucket or a full out yard sale. A graphic similar to the one below can be used during game broadcast.



See …. math can be fun.

If you want to have some of your own fun, I found an old webpage by Exploratorium that will let you input player speed and weights to measures collisions in Joules the way I had done above. I can tell the webpage is of significant age by the preset players you can choose from.

The Possible Connection Between Initial Kinetic Energy and Concussions

Now that the fun topic is over, I felt the need to bring up something a little more touchy and concerning about hits. The reality here is that the energy produced by an NHL hit is consumed by the player(s) body. Being made up of soft tissue this mean that bones, muscles and vital organs will consume all of that energy. The vital organ at most concern is the brain. Concussions have become a touchy subject in all sports these days. I would like to thank my friends here at Leafs Hub for giving me the green light to make suggestion on how RFID could be used to isolate players potentially hiding concussion symptoms after a big hit. We were all young and invincible once, some clearly more invincible than others. Some of us have even said “No problem guys, I am OK, I wanna play”

I once was diagnosed with a mild to medium concussion as result of a baseball to the chin. Being in my early 20’s, freshly married and no children I made a horrible decision. I decided to finish playing the game and the next one after that. I felt woozy, I heard my molars clank together and I would occasionally see spots or light ghosts from the field night lights. After the game was over I proceeded to drive myself to emergency. I received 6 stitches in my chin and was told to call for a ride home due to my concussion diagnosis. I then pretended to go outside call my wife for a ride. Instead I jumped into my brand new pick-up and drove myself home. STOOOOOOPID. Looking back on that day and the couple weeks after, I see nothing but fog. Everything is foggy in my memory. I did arrive home safe, and no one was hurt. The problem is, I could have easily passed out and killed myself or even worse a family like my own. All because of dumb decision.

I share that little part of my past because I know for a fact that there are players out there that will hide symptoms of a potential concussion to stay “in the game”. The age old argument is “everyone’s body is different”, this is true. BUT. If an early diagnosis of a mild concussion can be given, before another on ice incident happens that could possibly worsen the previous condition, the player in question could easily get back “In the game” sooner than if allowed to play. I have attempted to research if there is an exact collision measurement that could lead to a concussion. In my search I found some insightful pieces regarding football hits.

I found the following chart in this link.

football_tackle_G_force_Penn_State_UThis chart shows a football hit in relationship to other experiences

The chart above uses G-Force as a measurement of NFL hits. I strongly believe that with the proper research, something similar can be done showing a relationship between an NHL hit quantifier(I used Joules in my example), player weight and concussions. A simple cross reference chart like the one I have suggested could be used as a precautionary measure if a medical staffer or coach is concerned after witnessing a big hit. I am not suggesting that this could be something to prevent concussions but it could be used to prevent further damage to player who may be willingly playing with, or unknowingly playing with, a potential concussion. Concussions are real and dangerous.


Some love hits and some don’t. Some think they are useless and some believe they are required. Whatever side of the fence you are on , it doesn’t matter, they are a part of today’s game. To be honest, I love them. I hope they are here to stay. I think they are still one of the best ways to separate a player from the puck(Me thinking via this blog post, someone may eventually come up with a stat comparing hits vs turnover/separation success rate). Only goals get me to jump higher off my seat than a big, clean, open ice bone crusher. Even though I am huge fan of them I understand the risks involved with them as well. Inevitably I would understand if hits become even more controlled than they are today. Player safety is of course more important than the 11 o’clock highlight reel.

Thanks for reading


Please enjoy the following video …. enjoy it while it lasts




RFID in the NHL – Part 1

RFID in the NHL – Part 2

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