The Science of Skates
Skates used by Olympic speed skaters, figure skaters and hockey players are custom-engineered by materials scientists so that the boots and blades meet the demands for each sport. NSF-funded scientists Melissa Hines, Director of the Cornell University Center for Materials Research, and Sam Colbeck, formerly of the U.S. Army Cold Regions Lab, explain, along with U.S. Olympic hockey player Julie Chu, short track speed skater J.R. Celski, and figure-skater Rachael Flatt.
LESTER HOLT, anchor: The ice skates worn by this year’s hockey players, figure skaters and speed skaters are greatly different from those once used. Learn from this year’s winter Olympians and materials-scientists and researchers funded by the National Science Foundation how innovations in boot and blade design help skaters perform better than ever before.
HOLT: Speed skaters need them, to race around tight corners at break-neck speeds. Figure skaters need them, to glide, spin and spiral during their routines. Hockey players need them, to chase down pucks, and turn on a dime. Olympic Ice Skates – at first glance, they look like skates have looked for decades. But in fact – with innovations in materials science – skates are now specifically engineered to give the best competitive edge to the individual athletes who lace them up.
The engineering starts with the boot. Two-time U.S. Women’s Hockey player Julie Chu needs skate boots that are comfortable -- yet can support her feet for up to 20 straight minutes of high-velocity, high-intensity play.
HOLT: So she wears boots made from synthetic materials that form-fit to her feet when heated.
JULIE CHU (U.S. Hockey Team): You're really just warming them up so that the inside molding or the inside material is a little bit softer, and then you put your foot in it and it just molds to your foot as it cools down.
HOLT: Form-fitted boots also help the player apply more energy and force -- more directly -- to push off the ice and skate.
Dr. MELISSA HINES (Cornell University): And that's really important because any time your uh, foot is moving around in a boot, it's squishing back and forth that’s energy that's not going towards hockey, and you don't want to have that happen.
HOLT: Speed skaters like J.R. Celski have to make tight, high-speed turns, which means their ankles – and their skate boots -- have to flex.
J.R CELSKI (U.S. Speed Skating Team - Short Track): These skates are built from the base up, starting with the boot. They're custom made so they're carbon fiber mostly and they're very hard, but there’s a lot of flexibility in the ankle so when we are skating we can push out knees forward and get a lot of movement wherever we want to go on the track.
HOLT: Figure-skating boots are just the opposite: they have to be stiff -- support the ankle through all those axels, lutzes, and salchows. What space-age material are they made of? Layers of old-fashioned leather.
Dr. HINES: It turns out that nature is really good at making uh, materials. Things like leather have great attributes that are used still today in things like figure skates, where you want to have the right blend of stiffness and also movability, also suppleness.
HOLT: As for the skate blades – in one way, they’re all alike: made of high-quality steel. But blades, too, are engineered and designed for specific kinds of movement. Figure-skate blades, for example, have “toe-picks” – pointed teeth at the front of the blades – that skaters like Rachael Flatt can use to dig into the ice, to stop or launch a jump. And to help her maneuver gracefully on turns, the bottom of each blade has a center groove separating two thin separate edges.
RACHAEL FLATT (U.S. Figure Skating Team): It’s tilted a little bit to the inside or to the outside. When you're tilting to your right, you're going to be on the inside of this blade, but when on your right skate, it will be outside of your blade.
Dr. HINES: So the little sharp edges help you steer, the sharp parts of the skate can actually dig into the ice and give you a little bit of extra impact, a little bit of extra oomph.
HOLT: Blades on hockey skates are built for speed. They’re shorter, lighter, to help hockey players skate fast, stop fast, and turn fast.
CHU: We have to always be going forward and backwards as well as transition. So I think the shorter blades allow us to be a little bit more agile on the ice.
HOLT: Speed skaters, who don’t have to make quick pivots, have longer and wider skate blades, to help them glide. It’s surface physics: The movement of the blade over the ice creates friction, which generates heat – which creates a thin layer of melt-water for the skate to glide on. A wider, longer blade generates more heat, more melt water, more glide, it’s an advantage to keep the blade on the ice as long as possible – whenever contact is broken, heat is lost.
Dr. SAM COLBECK (U.S. Army Cold Regions Lab): I see that in my temperature measurements with skates, because when you glide, the skate is heated up. When you pick it up, it's cooled. So there'd be an advantage to keeping the skate on the ice, and continuously keeping the skate bottom warm.
HOLT: That's the advantage of the clap-skate, used in long track speed skating: A hinge connects the skate to the boot – allows skaters to pick up their heels – yet leave their skate blades in contact with the ice just a bit longer, to glide farther, faster on the long straightaway’s. Short track speed skaters who don’t have long straightaway’s -- wear skates with blades fixed in a carefully calculated position.
CELSKI: Our blades are actually set up in our boots, so that when we are angled, our boots don’t rub on the ice -- we are able to lean as much as we can without, you know what’s called “booting out” on short track.
HOLT: The science and engineering of boots and blades - for Olympic contenders, what they'll wear around their necks can depend on what they wear on their feet.