The Radius of Hollow (ROH) is the little groove at the bottom of your blades. Do you know what your ROH is? If you don't, well, I expect that you often wonder why your skate blades seem to change from sharpening to sharpening. Some unscrupulous sharpeners will just put the ROH on your blades that they have on the machine.
I've been skating for nine (9) years and not once has a coach ever mentioned ROH to me. Oh, boots, blades, things like that. But the single most important thing about skating, the ROH, nope, nada.
I'm not going to really explain a lot of that here. I can tell you what I learned from my skate tech. The hollow you need depends on the temperature of the ice, the type and level of your skating, and the discipline you're skating in.
The smaller the hollow, the 'grippier' the blade it. The 'flatter' the hollow, the 'glidier' the blade.
I think (based on discussions with my tech) that there are four usual hollows for figure skaters: 3/8", 5/16", 7/16", and 1/2". Hockey players have five hollows, depending on position, weight, and skill level.
So, I've experimented. I skated one winter w/ 3/8" because it was cold and the ice was hard and I wasn't bending my knees enough. Then for the last few years, I've been at 7/16".
7/16" is a bitch for the first three hours when I try to stop going backwards.
So, this time I waited too long to get a sharpening on my 7/16" ROH, and I noticed that 'oooh, baby' those dead edges make my turns just float across the ice. So I went to my tech and asked for a 1/2" ROH to see if I could keep that skill.
"You might not be able to detect it," he said.
To make a long story short: Yes I can tell. 1/2" is a lot more glidey, but just as grippy in the stops. OTOH, the grippy in the back stops goes away fast. The downside with the 1/2" hollow is that it loses its edge pretty
fast. I'm debating investing in a Pro-filer to touch it up between
The interesting thing is, with the 1/2" ROH, my back doesn't hurt as much as it does with the 7/16". I have to bend the knee more with 1/2" so maybe the ROH change is forcing me to hold my body correctly. Beats me.
Do you know what your hollow is? Do you specify it when you go to your sharpener? Does your coach make suggestions to you? I think these are all important when you buy your own skates and take your blades to a sharpener.