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Goalie Tips
8. The Science of Goaltending
"Measuring Reaction Time"
Reaction time
In a high-speed sport such as hockey, players' reflexes are
very important. A player's reaction time can often determine the outcome of a
game. A good example of this is the reaction time of goalie. Many fans of the
game have watched in awe as a goalies limbs flail about saving pucks left and
right. It's amazing that most of the games remain relatively low scoring
after watching powerful players rip 90-mile-per-hour (144 km per hour) slapshots
at the goal.
Just how fast is a goalie's reaction time?
Let's see what reaction time is required of an NHL
goalie when an opposing player launches a speedy slapshot towards the net.
If the opposing player has time to tee up and get solid wood on the puck, he
could easily be facing a shot of up to 90 mph. The reaction time of the
goalie can be calculated using the equation
Describing motion is a part of mechanics known as
kinematics. Physicists call this a kinematic equation. |
If someone shoots from the blue
line, a rather generous distance of 60 feet, the time it takes for the puck
to travel to the net is
To translate 90 mph into feet per second (5280 feet =1 mile/
3600 seconds =1 hour), then
90 x 5280 = 475, 200 feet per hour.
| 475, 200 |
= 132 feet per second = 90
mph |
| 3600 |
| 60 feet |
= .456 seconds |
| 132 feet per second |
This doesn't allow very much time for the goalie to move
his/her body along with all that equipment over to save the puck. Try
testing your own reaction time, for a better understanding of what a goalie
has to do. |
| How fast are you? You can measure
your reaction time with just a yardstick and some help from a friend. Rest
your arm on the edge of a table or chair, with your hand hanging over the
edge (this prevents you from dropping your hand down to match the
yardstick's motion). Hold your thumb and index finger about an inch apart,
and have a friend hold a yardstick so that its bottom end is just between
your two fingers. Without warning you, have your friend drop the yardstick
and, as fast as you can, close your fingers on the stick.
Note the inch reading where your fingers hold the stick. For most people,
about six inches will have fallen through before they can grab the
yardstick.
If you want to convert the distance the yardstick fell to
a reaction time, use the following table: |
| Inches Fallen |
ReactionTime in Seconds |
| 5.0 |
0.161 |
| 5.5 |
0.169 |
| 6.0 |
0.177 |
| 6.5 |
0.184 |
| 7.0 |
0.191 |
| 7.5 |
0.198 |
| 8.0 |
0.204 |
| 8.5 |
0.210 |
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| This grab at 7 inches is good enough for a web
developer but wouldn't cut it for a goalie. |
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Thinking of going pro?
The average person usually catches the yardstick around 6-8 inches; this
translates to a reaction time of .177 to .204 seconds. Thinking of going
pro? Wait until you consider this next situation.
If the opposing player uses the room between him and the net to his
advantage and skates up so that he tees up at a distance of twenty feet from
the goalie, he will effectively minimize the time that the goalie has to
deflect the puck out of the way. If the puck is traveling at 100 mph at the
time it reaches the goalie, let's see how quick he has to be:
Time = d/t = 20 ft/90 mph = 0.152 sec.
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