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• Stetching - Help or Hindrance
• Job Rotation - Is it an effective solution for reducing injury risk?

Stretching - Help or Hindrance?

Many of us have heard repeatedly that stretching before and during work or sporting activities is beneficial and will help us to reduce our risk of injury. But is this really true? Recent research indicates that depending on the type of stretching you perform, you may actually be increasing your injury risk rather than reducing it!

In the 70's, "ballistic" or bouncing type stretching was popular. Then research studies indicated that if you stretched the muscle very quickly, it would tighten as a protective mechanism, thereby defeating the purpose of stretching the muscle. To increase flexibility, a stretch-and-hold technique was then advocated (and continues to be often recommended) where you stretch the muscle to the edge of discomfort and hold to allow the muscle to stretch out. Hold time suggested for this technique, as recommended by differing research studies, is anywhere from a few seconds to 10 minutes or more.

As it turns out, the stretch-and-hold technique is a great way to injure yourself if you're going to be doing dynamic activity (activity that requires motion), especially where you need to generate force during the motions involved. Have you ever watched a sprinter prepare for his race? You'll see lots of jogging, accelerations, jumping and bounding, but no static stretching. Talk to these athletes and they'll tell you that they feel "too loose" or sluggish if they perform static stretching before a run.

In fact, research has verified that those who do static stretching before a running race get more injuries. Static stretching, we have recently come to understand, temporarily dampens receptors in the muscles so that they do not respond as quickly to the signals that tell them to fire. As a result, muscles cannot generate as much force after static stretching and therefore the injury potential increases.

Does this mean static stretching is all bad? No. If your job tasks are static, in other words, don't involve a lot of motion or effort (e.g. monitoring a control panel) static stretching is still an effective way to stretch the muscles. It's also appropriate to do at the end of the day when your dynamic activities are done.

However, if your job is active and requires force generation, do not perform static stretching. Instead, dynamic stretching - keeping the muscle moving through a range of motion during a stretch - is recommended. Examples of dynamic stretching are arm circles, wrist circles, and leg swings, or take any of the exercises that you used to do for static stretching and move in and out of the stretch. But no bouncing like the old ballistic stretching - keep it moving. For those of you involved in sporting activities, the same principle applies.

Remember as well, regardless of the kind of stretching that's appropriate for the type of activity you'll be doing, your muscles MUST be warm before you stretch. Trying to stretch a cold muscle is a prescription for injury. A hot shower, walking briskly or climbing stairs are all ways to warm the body before stretching.

Margo Fraser, M.Sc., CCPE

Job Rotation - Is it an effective solution for reducing injury risk?

Job rotation is an often used tactic in industry to reduce injury risk, but just how effective is it? Research conducted at the University of Waterloo has shown that, in some cases, injury risk is increased rather than decreased.