Terminology
For an extensive glossary of terminology, see Glossary of curling.Terms used to describe the game include:
The ice in the game may be fast (keen) or slow. If the ice is keen, a rock will travel farther with a given amount of weight (throwing force) on it. The speed of the ice is measured in seconds. One such measure known as "hog-to-tee" is the amount of time that a rock will take from the moment that it crosses the hog line at the throwing end to come to rest at the tee line at the playing end. If the ice is slow, the rock will have to have more weight in order to reach the tee line and would reach the tee line more quickly. Increasing the weight of the rock will increase the momentum of the rock. Thus, the speed of the ice (in seconds) is lower if the ice is slow than if the ice is fast, in which case the rock would have to be thrown more slowly and would take longer to get there. The time is longer because the stone takes longer to slow down if the ice is keener.
The "hog-to-hog" speed is the speed of the stone and is the time in seconds the rock takes from the moment it crosses the near hog line till it crosses the far hog line. If this number is lower, the rock is moving faster, so again low numbers mean more speed. The ice in a match will be somewhat consistent and thus this measure of speed can also be used to measure how far down the ice the rock will travel. Once it is determined that a rock taking (for example) 12 seconds to go from hog line to hog line will stop on the tee line, the curler can know that if the hog-to-hog time is matched by a future stone, that stone will likely stop at approximately the same location. As an example, on keen ice, common times might be 16 seconds for guards, 14 seconds for draws, and 9 seconds for peel weight.
The back line to hog line speed is used principally by sweepers to get an initial sense of the weight of a stone. As an example, on keen ice, common times might be 4.0 seconds for guards, 3.8 seconds for draws, 3.2 for normal hit weight, and 2.9 seconds for peel weight. Especially at the club level, this metric can be misleading, due to amateurs sometimes pushing stones on release, causing the stone to travel faster than the back-to-hog speed.
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