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Ergonomics

Manual Material Handling/Back Safety Tips

Revised 120917

Work may cause a back injury or it may aggravate a pre-existing back problem. In either case, the resultant low back pain can be extremely disabling. This document contains tips on how to prevent low back pain and what to do if you already have it.

Posture and Body Mechanics
Work Organization
Physical Fitness
What To Do If You Have Back Pain
Pain Isn't Always Bad
Office Work
Non-Office Work


POSTURE AND BODY MECHANICS

Before reading the remainder of this section, take a look at the link below. It contains excellent illustrations of many of the lifting techniques described in this section.

Lifting Techniques (U.S. Army Center for Health Promotion and Preventive Medicine)

Many of us know these techniques already but don't always use them. This may be because performing a task using proper posture and body mechanics is usually slower than working in a less safe manner. Consequently, we must remember that:
Any time saved by taking a risky short cut is quickly lost if we get hurt and are unable to work.
Back injuries can develop slowly over time.
Performing an activity incorrectly may not hurt, however this doesn't mean that we are not damaging body tissues.

Even by using proper body mechanics, some objects will be too heavy to move without help.
Get help from a co-worker.
Split up the load into smaller, lighter loads.
Find some other way to move the object (e.g., cart, dolly, etc).
If you have any question about the safety of a task you are asked to perform, let your supervisor know. (Although it is best to talk with your supervisor, you may also report concerns to your JHSC or Health and Safety Representative.)

Some of the important principles are summarized in this poster with more details provided below:

Poster - Manual Material Handling Back Injury Prevention (PDF)

1) Activate your core muscles.

To protect your spine, tighten your abdominal muscles. This will generally activate the rest of your core muscles.

2) Maintain the natural inward curve of your low back

This curve has a tendency to flatten when you bend or sit, increasing the strain on the low back.

Looking forward (not down) during a lift helps to maintain this curve.

3) Keep objects that you are lifting or carrying close to your body.

The farther the object is from your body, the greater the strain will be.
Slide objects close to you before lifting them
When squatting to lift, do not let your knees get between yourself and the load. If the load is not too wide, spread your knees apart so you can bring the load close to your belly. (NOTE: This is difficult to do while wearing a dress or skirt. Wear comfortably fitting pants.)

4) Work with your upper body as close to upright as possible.

Leaning forwards or sideways puts extra strain on your back. Wherever possible:

Position items that you handle so that your hands are in the safe lifting zone (between mid-thigh and shoulder height).
Keep loads that you must handle manually off of the floor (unless their handles are in the safe lifting zone).
For low level work, bend your knees, squat or kneel. Consider a longer handled tool.

If you can't work upright
, resting a hand or elbow on your knee or another object will take some of the load off of your back. Other objects that you could lean on:
a nearby table or chair.
the top of a deep container into which you must reach.
any surface within a comfortable reach.

5) Minimize twisting of your spine.

Move your feet or swivel your chair instead of twisting at the waist or neck, so that your hips and shoulders are facing in the same direction.

6) Push, don't pull, whenever possible.

Pulling an object you are facing puts more strain on back muscles than pushing it.
Exceptions:

Some objects don’t move as easily when pushed, especially when terrain is bumpy or rough.
Pushing may not be safe if the object you are pushing obstructs your vision and you can’t see where you are going.


If you must pull something, try to use 2 hands to avoid twisting.

7) Use sudden quick movements with care.

If not performed carefully, sudden quick movements will put more strain on your back than moving more slowly (e.g., avoid jumping from loading docks or high vehicles).

7.1) Unexpected movements are more likely to cause injuries than deliberate movements.

Wear shoes with good traction and support and keep walking surfaces clear to avoid slips, trips or falls.
Make sure objects you are moving do not shift during transport.
Proper storage will minimize injuries related to sudden movements to catch falling objects.

8) Use a footrest for prolonged standing.

A footrest (approx. 8 inches high) can be used to help avoid static postures.
Vary standing postures by shifting body weight from both to one or the other leg.

For more information on standing work refer to:
Working in a Standing Position - Basic Information (Canadian Centre for Occupational Health & Safety)

WORK ORGANIZATION

Frequent short breaks are better than infrequent long breaks

There is a limit to how long we can perform any activity without becoming uncomfortable or even injuring ourselves. However, the most important determinant of risk of injury is not the total time spent performing the activity. What is most important, is how long the activity is performed continuously without interruption.
Example:

Performing an activity for 2 hours all at once has a higher risk of injury than performing the 2 hours of activity in shorter segments, alternated with less fatiguing activities.

This is because strained muscles heal if given time to heal and the healing time required depends on how long the muscles are strained. If muscles are strained for a long time, they'll need a relatively longer time to recover.
Examples:
A 10 second rest every 10 minutes is more helpful than a 60 second rest every 60 minutes.
A 5 minute rest every hour is more helpful than a 40 minute rest every 8 hours.

There are no hard and fast rules for what rest frequency is best for all tasks and all people. Adjust your own rest frequency so that you are resting before discomfort occurs rather than in response to it. Once discomfort occurs, muscles will take much longer to recover.

A rest break doesn't mean that no work can be performed

A specific muscle group can be rested by:

Switching to a task that puts less strain on that muscle group.
Alternating sitting and standing tasks.
Alternating tasks that involve a lot of bending with those that utilize more upright postures.
Performing the task using different muscle groups (e.g., use your right hand instead of your left).
When standing in one spot for prolonged periods, vary your posture by placing one foot on a footrest.
Performing some stretches.

Take extra care & warm-up at high risk times

After a day off
First thing in the morning or just after waking up
After breaks or long periods of inactivity
After sitting
After driving (the combination of sitting and vibration is especially hard on the back)

PHYSICAL FITNESS

Being physically fit will decrease the chance of hurting your back. Physical fitness involves proper diet, exercise and rest.

Diet

For more information, refer to:
Canada's Food Guide to Healthy Eating
Healthy Eating on Campus

Exercise

Most forms of physical activity will strengthen the back, as the back is central to any whole body movement. For more information:
Canada's Physical Activity Guide to Healthy Active Living
Arthritis Society - Tips for Living Well (not just for people with arthritis)

Exercises that target the back specifically:
Good and Bad Exercises for Low Back Pain (WebMD)

Rest

Proper rest enhances physical fitness. In addition, when we are well rested we are less likely to make mistakes that can lead to injuries.

WHAT TO DO IF YOU HAVE BACK PAIN

1) If your back problem makes it difficult to perform your job, inform your supervisor immediately. The severity of a problem can be minimized if proper action is taken early enough.

2) See a doctor.

The National Institute of Neurological Disorders and Stroke (link below) suggests that you should contact a doctor if there is not a noticeable reduction in pain and inflammation after 72 hours of self-care.

To help make the most of a visit to your doctor, refer to:

Questions To Ask Your Doctor About Musculoskeletal Disorders

The following links describe some common treatments:
National Institute of Neurological Disorders and Stroke (USA): Back Pain
The Arthritis Society (Canada): What can you do about chronic back injury?
Spine-health.com

PAIN ISN'T ALWAYS BAD

Pain is an important sensation as it can tell us if what we are doing is causing harm.
However, doctors may tell you to remain active after a back injury even if it hurts, as inactivity can lead to further tissue weakening. Some tissue challenge is necessary for proper healing (e.g., movement of a joint after a cast is removed). This kind of pain is not associated with harm.
Here are some characteristics of pain that is not associated with harm:

You bring it on yourself purposefully
You are in full control of intensity
Leads to stronger muscles and more flexible joints
Signs of injury (e.g., swelling) become less over a period of several days
Pain is less as you continue to repeat the activity over the course of a few days

OFFICE WORK

There is more information specific to back pain and office work at:

Sitting and Back Pain

NON-OFFICE WORK

In addition to everything described above, there is advice on specific non-office activities available in the Ergonomics Site Index listed under the heading Activities, Non-office.