by Tim Falconer ([email protected])
The game of tennis has enjoyed a revolution in technology in recent years as wooden rackets gave way to lighter, tougher models made of space-age composites. Now hockey sticks seem headed the same way ‹ though the transition will be trickier. "You primarily hit a tennis ball one way," points out Blaine Hoshizaki, vice president of research and development with Canstar Sports Group Inc. of St. Jerome, Que. "But you use a hockey stick to control the puck, to pass the puck, to receive a pass and to take many different shots, so it¹s more demanding to design a composite hockey stick."

In the good old days, sticks were made strictly of wood‹carved from a single piece of ash, maple or elm. Wooden sticks reigned for decades, but their organic base made individual models vary greatly in strength and stiffness. In the late 1960s, manufacturers began to make stiffer, more durable sticks whose blades and shafts were strengthened with fibreglass and, later, lighter and stronger synthetics such as graphite and Kevlar. In the 1980s came the vogue of two-piece sticks with consistently strong aluminum shafts and replaceable wooden blades. The problem there was that aluminum shafts were too stiff for average recreational players to get the best use of them.

The latest answer? Unbreakable one-piece sticks made of composite materials whose properties can be varied from stick to stick, to suit different levels of players, and even within one stick itself, to suit the nuances of high-level play. The flexibility of composites is rooted in their fundamental structure. Composites consist of a fibre ‹ carbon or glass, for instance ‹ cooked in a resin. Rene Bourque, director of research and development at Canstar, explains the fibres act like steel reinforcing bars in a cement structure. The result is a light, strong, crack-resistant material.

The shaft of a hockey stick can attain different properties according to how the fibres are oriented in its structure. If the fibres run longitudinally down the shaft, for instance, it will be relatively flexible, or bendable; fibres running at a 45-degree angle across the shaft will tend to make it stiffer. To exploit the full potential of the composite stick, Canstar researchers are making a close study of how the stick is actually used in high-level play, studying the split-second dynamics of the slapshot, for instance. "When we know exactly what we want, we can achieve it," says Bourque. "All the dynamic date is like having a map to an address."

To give one example, in a slapshot a player "loads" energy in the shaft of a stick by bending it as it strikes the ice behind the puck. Very stiff shafts can benefit strong players who can load a large amount of energy into them, but they¹re of little use to players who are too weak to bend them at all. Composite sticks could be made with shafts that offer stiffness of up to 19 kilonewtons per metre for pros, and as little as 11 kilonewtons per metre for kids. And sticks could be built with a shaft that is most flexible, or "whippy," in just the area that optimizes energy load for a successful slapshot. At the same time, researchers are also working on composite blade technology, seeking to translate the concepts that players call "feel" or "playability" into the more precise terms of physics and engineering.
 
 

From "How Hockey Works" (Equinox, January/February,1994).