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The physics of deep edges
The 2 main factors that define the depth of the edge in fs are the speed they travel with and the radius of the curve they are marking.
This is the formula that descrive it, where α is the angle between the ice and the line from the blade to the center of mass, v is velocity
This is the formula that descrive it, where α is the angle between the ice and the line from the blade to the center of mass, v is velocity
R the radius and g the gravity (9.81m/s²)
For reference this is what a tan^(-1) function ploting looks like. Which means the smaller we make the fraction, the deeper the edge will be. So the smaller the curve and/or the faster the skater is, the deeper the edge will be
For reference this is what a tan^(-1) function ploting looks like. Which means the smaller we make the fraction, the deeper the edge will be. So the smaller the curve and/or the faster the skater is, the deeper the edge will be
SMALL CURVES
In fs, the smallest curve every skater does is the loop turn. I chose the back inside loop to compare because skaters dont separate their limbs as much as in the forward outside loop, so it's easier to estimate where the center of mass is.
In fs, the smallest curve every skater does is the loop turn. I chose the back inside loop to compare because skaters dont separate their limbs as much as in the forward outside loop, so it's easier to estimate where the center of mass is.
Just mind the loop turn isnt a perfect circle, however it has more or less this shape. This means the radius of the curve is significantly bigger at the beggining and end, than in the middle. So I tried to take the following screenshot between the red lines marked
Here two skaters with similar position and camera angle. Both turns are executed in a stsq.
For a similar size of the ice mark the faster skater will have a deeper edge
For a similar size of the ice mark the faster skater will have a deeper edge
For reference of the speed, here the video of first one
And here the video of the second one
Here another comparison from the back view. This time it's the same skater, but the one on the left isnt executed in a stsq, it is used as part of a transition and right before stopping. Again both have similar body position
Videos for comparison of the speed
Second one
BIG CURVES
A small turn like the loop dont allow a lot of speed as it would need an edge too deep to be controled in such position, so lets take a look at bigger curves.
A perfect one for comparison is the exit of a jump as the body position is always very similar
A small turn like the loop dont allow a lot of speed as it would need an edge too deep to be controled in such position, so lets take a look at bigger curves.
A perfect one for comparison is the exit of a jump as the body position is always very similar
Here two skaters landing a 2A with speed out displayed
Note that the radius of the curve might not be as similar as in the previous case, however, as the velocity is squared in the formula, speed is more important for the final edge which gives that clear difference between them
Note that the radius of the curve might not be as similar as in the previous case, however, as the velocity is squared in the formula, speed is more important for the final edge which gives that clear difference between them
