Back Care and Standing Work

 

According to the latest injury figures from the Bureau of Labor Statistics, each year there are over 880,000 cases of back injuries that account for 1 in 4 nonfatal occupational injuries involving days away from work. In most sectors of industry, back injuries now rank either second or third overall (Bureau of Labor Statistics, 1998).

Back care for standing work
Over our lifetimes, 8 out of 10 people will experience a back injury and back pain. Most back injuries are painful, debilitating, and life changing. As a former sufferer, I know firsthand how important it is to learn how to improve the health of the spine and take steps to prevent back injury.

Training to prevent low back disorders requires both a working understanding of the spine and knowledge of back injury risk factors.


Back Basics

The spine is a flexible structure that consists of 24 movable bones, called vertebrae (7 in the neck, 12 in the chest, 5 in the lower back) that are connected by tough ligaments and separated by pads of cartilage, called intervertebral discs, that act as shock absorbers and allow the flexible movement of the spine, especially at the neck and the lower back.
When we are standing, the spine naturally curves both inwards and outwards. The inward curve, a position called lordosis, curves towards the front of the body at the lower back and neck regions. The outward curve, a position called kyphosis, curves towards the back of the body at the chest. Whenever we bend over, while standing, the five lumbar vertebrae of the lower back change position and shift from being in lordosis to being in kyphosis when we are completely bent over. The lumbar vertebrae change position again as we stand up from being bent over returning to lordosis position. Think about how much you move around and bend during a normal day. The lower back is probably the most used part of the spine, which likely accounts for the fact that low back pain and injury disorders are the most common back complaints.

Causes of Low Back Pain:

• straining the muscles or ligaments
• pressure on the intervertebral discs
• nerve compression or entrapment
• damage to the vertebra

In a review of the research literature, the National Institute of Occupational Safety and Health concluded that “muscle strain is probably the most common type of work or nonwork back pain” (Bernard, 1997). That’s good news for ergonomists because it means that we can investigate ways to reduce the effort of work to minimize injury risks.

The health of the intervertebral discs plays a major role in back injuries. If discs are damaged and begin to degenerate, the back loses flexibility and the capacity to absorb the daily forces associated with standing, moving and working. Intervetebral discs don't have a normal blood supply, instead, as the discs change shape as we move around, nutrients are drawn into the discs and waste products are pumped out. Moving the body helps this process by intermittently changing the forces on the discs. Moving around helps to keep the spine healthy.


What are the risk factors for low back injuries?

With data from over 40 research studies we now have a pretty good idea of the major risk factors for back injuries. These factors are:
1) heavy physical work
2) lifting and forceful movements
3) bending and twisting (awkward postures)
4) whole-body vibration (WBV)
5) static work postures.

These work-related risks for injuries can occur separately or in some combination. The more of these factors happening at any one time the greater the risk of injury.

What does all this mean for Standing Work?

When we are standing, the pressure on the intervertebral discs of the lower back is fairly low, much lower than say when we sit unsupported on uncomfortable bleachers. But, standing uses about 20% more energy than sitting, so we get tired more quickly and look to sit down. When we are standing we need to bend down to pick up objects or stretch up to get overhead objects. In all of these instances there is an increase in the forces on the lower back, and that’s when an injury is most likely to occur.

.5 Tips to minimize injury risks during Standing Work.

The following tips will help you to minimize your risks of low back injury when you are doing standing work:

1) Remember to move around -Even the guards in Arlington cemetery can’t stand to attention all day long. Moving is important to keeping the spine healthy and it will also help to improve circulation and reduce muscle fatigue.

2) Take breaks and stretch - Recent research has confirmed that frequent brief rest breaks help to reduce fatigue and musculoskeletal discomfort. Gentle stretching during a break will help to ease muscle tension and improve circulation.

3) Watch your posture - Pay attention to how you are standing!

• Stand in a stable posture with you feet on a firm surface.
• Try to avoid twisting the lower back around to reach things and move your feet so that your whole posture changes instead.
• Try to minimize bending movements. If you must bend for objects that are in front of you try to bend at the knees rather than the back. If you must bend for objects to the side of you try changing your stance so that you are facing the object, and then bend down at the knees.
• Avoid overreaching - if you must reach up to a high level, get something firm to stand on, such as a stool of steps.
• Avoid reaching over obstructions - if possible move the obstructing object or change your position before you reach for what you need.

4) Lean where you can - Leaning on a solid support helps to reduce fatigue when your standing. This might be a support that you can lean back against, a support that you can lean against sideways, or a support that you can lean forwards against or hold on to.

5) Keep your back strong and supple - try to exercise to strengthen your back muscles, and do activities, like Yoga, to maintain flexibility.

Written by Alan Hedge, PhD, CPE