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The secrets to safe snow shovelling Add to ...

The I-Shovel Autonomous Robotic Snow Shovel is programmed to spring into action the moment snow begins to fall. It is equipped with a digital brain and a plastic scoop, and it works until the flurries stop, oblivious to fatigue or depression.

It sounds like every Canadian's dream - and for the moment, that's all it is. The I-Shovel exists merely as a working prototype in search of investors. That means most of us will be trudging out to our driveways this winter, armed with little more than a primitive tool that traces its origins to the Pharaohs: the shovel.

Although you can dress it up with bent handles, polycarbonate blades and even a wheel - as the makers of a version called the Wovel have done - the snow shovel is a model of simplicity. But that doesn't mean we know how to use it.

"Technique is important," says Andrew Drewczynski, an ergonomist at the Canadian Centre for Occupational Health and Safety. "But most people don't know anything about it. They just go out there and start flailing away."

 

Although few outside the world of engineering would appreciate its subtleties, shovelling snow involves a complex set of physical and mechanical interactions. Holding the shovel too high on the shaft, for example, results in decreased leverage, overloading the arm muscles. Excessive bending at the waist overworks the torso by moving the lifted weight further from the body's centre of gravity.

By outfitting shovellers with heart-rate monitors and digital strain gauges, researchers with the Liberty Mutual Research Institute for Safety Center for Safety Research in Massachusetts learned that poor technique is both inefficient and hazardous. Their results were published in a 2001 paper titled The Effect of Technique and Shaft Configuration in Snow Shoveling on Physiologic, Kinematic, Kinetic and Productivity Variables.

The researchers concluded that a bent-handle shovel design can reduce back strain by allowing a shoveller to stand more upright. Other experts have come to different conclusions, deciding that a straight-handled shovel optimizes leverage by allowing a greater range of lower hand positions.

By analyzing the technique of professional shovellers such as grave diggers and construction workers, ergonomic experts have learned that the secret to efficient shovelling is moving a relatively light load at the correct rate. For most people, the ideal load of snow per shovel-full is five to seven kilograms. Each shovel stroke should take four to five seconds, or 12 to 15 strokes per minute. Although the greatest theoretical efficiency is achieved at 18 to 21 strokes a minute, this is an Olympic-type standard, unsustainable for all but the most powerful and well-conditioned.

How far you throw the snow is also crucial. After extensive studies, experts have generally concluded that the optimal throw distance is about one metre.

Mr. Drewczynski says many people bring a deeply flawed approach to the task of shovelling snow. "They don't like doing it, so they try to get it over with as fast as they can. They overload the shovel and they try to work too fast."

Another common mistake Mr. Drewczynski sees is improper equipment application - like using a wide, plow-style shovel to lift and throw loads of snow. For digging and moving snow, most people should use a light shovel with a relatively small blade. Mr. Drewczynski says many consumers are seduced by elaborate new shovel designs. But he believes in sticking with the tried and true: a straight-handled shovel with a properly sized blade and a D- or T-shaped handle on top.

"The shovel is a very old tool," he says. "The best design has emerged over time and it's not easy to improve. The majority of the new designs I see are just marketing gimmicks. People already have a shovel, so companies are always dreaming up ways to sell them another one."

Follow on Twitter: @cheneydrive

 

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