The earliest skates were made mostly of horse bones, but other bones were also used depending on the animals available, Formenti said.
Holes carved in the ends of the bones were likely strung with leather straps tied around the skaters' feet.
Woodcuts from the 1500s show bone skates being used together with a stick, which was pushed between the legs to help the user pick up speed.
To study the energy efficiency of this early ice-skating, Formenti's team tested replicas of bone skates at an ice rink in the Italian Alps.
The researchers measured five skaters' heart rates, oxygen intake, and speed while maneuvering on the blades.
The skates took some time to get used to, Formenti said, but "once you get the movement pattern, they glide really well."
"The oily external surface of the animal bones makes a natural wax which limits resistance to motion."
The team then constructed mathematical models and computer simulations of energy use for 240 6-mile (10-kilometer) skating trips across different parts of northern Europe.
"This research suggests that ancient Finland would have been the most practical birthplace of the now popular winter sport," the authors write in their paper.
Other studies by the same scientists have shown how fast and how far people could skate at various times in history, as bone blades gave way to iron and then to steel.
The earliest skaters were probably not fast. The people testing the bone skates for the latest study reached an average speed of about 5 miles (8 kilometers) an hour.
Modern speed skaters, on the other hand, can reach speeds of up to 37 miles (60 kilometers) an hour.
Skates and Skis
Steven Vogel is a biology professor at Duke University in Durham, North Carolina, who was not involved in the study.
The skating research is "especially important, because just about no one else does this kind of thing—showing how biomechanical work can reveal things about history, prehistory, and anthropology," Vogel said.
Like with ice skates, other modes of transportation probably developed as people searched for more efficient ways of getting around, Formenti added.
"Cross-country skis seem to have developed in Scandinavia at about the same time as bone skates," he said.
(Related news: "Skiing: From the Stone Age to Torino" [January 31, 2006].)
"In Scandinavia there were heavy snowfalls, and skis allowed people to move around the woods without sinking in the snow with bare feet."
Long, flat skis redistribute the wearer's weight, lessening the depth of each step, while heat from friction melts a thin layer of snow underneath, allowing the wearer to glide over the terrain.
"The origins of skis and skates as passive tools enhancing human-powered locomotion share common roots, probably small wooden plates," Formenti said.
"These became longer and wider skis on snow or shorter and thinner plates—and, for sure, animal bones—used to glide on ice."
Free Email News Updates
Sign up for our Inside National Geographic newsletter. Every two weeks we'll send you our top stories and pictures (see sample).
SOURCES AND RELATED WEB SITES