Heavy and repetitive work - Kunnskapsbasen
Heavy and repetitive work
If you work at tasks that involve heavy lifting and/or are repetitive or monotonous, you may find that your work causes muscle and skeletal pain. Here are some tips for avoiding these kinds of problems.
Norsk versjon - Tungt og ensformig arbeid
Topic page about HSE | Pages labelled with ergonomics
Many tasks are heavy and/or consist of monotonous, repetitive motions that also involve awkward or problematic working positions. Movement and strain are good for your body, but if the strain is too great, it can cause problems.
Address the problem before it gets out of hand. It is easier to prevent injury than healing an already existing injury.
Heavy work is defined as one or more tasks that separately or together can overload an employee's muscle and skeletal system. This type of work often involves prolonged heavy, physical work that requires a lot of strength and energy.
This kind of work often includes lifting, carrying and pushing.
- Machinery or other technical aids should be available if the worker has to repeatedly lift weights of 25 kg or more.
- Standing, single lifts of 25 kg under ideal circumstances are safe for most people. Lifting from hip height requires the least amount of strength. Avoid heavy lifts from a seated position.
- A worker's individual technique for heavy lifting must be adjusted to that person, and to the specific work situation where the lifting is performed. The strain of lifting is affected by:
- The weight and shape of the object being lifted
- The distance from the body at which the object must be held
- The height of the lift
- Lifts with simultaneous twisting of the back, which will increase the strain on your back significantly
- Muscles work statically while carrying. For that reason, it is important that you do not carry objects over too long a distance, and that applicable aids or machines are available.
- The strain is determined by the weight and shape of the objects you are carrying. Keeping the object close to your body places less strain on your body.
- You should not carry heavy objects for more than 20 meters on a flat surface. If you have to carry weights up the stairs, one step equals a carrying distance of approximately 1 meter.
- When pushing, your own body weight can do part of the work. The strain on your body will depend on how much force you need to start the motion, keep the motion going and stop the motion.
- Frequent restarts, stops or changes of direction increase the strain.
Repetitive work is work that consists of one or a few simple operations that are repeated so quickly or for such a long time that it can cause muscle and skeletal pain.
- Working at a high tempo has the same effect as static muscle work, where a few muscle groups are subject to unbalanced strain over a long period of time. It is important to shift between different tasks and working positions to create variation throughout the workday.
- If you are unable to vary your working situation, you should set aside time for rest and restitution.
- Employees should be able to plan and control their own workday with regards to tempo and breaks.
Bad working positions
Working positions and motions are decisive with regards to the strain imposed on the body and any resulting injury. Work that requires the employee to stay in a specific working position or make specific motions over a long period of time are not good.
When in motion, the muscles work dynamically and shift between tension and relaxation.
When one specific position is maintained over a period of time, the muscles work statically, and even work that appears to be easy at first will quickly overstrain the muscles.
Over long periods of time, it is especially unfavourable to work:
- In a stooping position
- In bent or twisted positions
- Far away from your body
- At and above shoulder height
- In a crouching or kneeling position
- Standing up
- Sitting down
- With joints in an extended position
The working height must be adapted to the nature of the work, in order to avoid strain on your body. If you are performing different tasks at a workbench, it is best if the height of the bench can be adjusted.
- When working with light objects, performed your work at hip height to avoid a stooping position and allow your arms to move freely.
- When working with heavy objects where force is applied vertically or horizontally, the height at which you work should be lower.
- Work that requires precision and good vision should be performed at a higher working height.
An ergonomic risk assessment must be performed during planning, designing and performing of manual work. The following should be taken into particular consideration:
- The nature of the object
- Physical exertions
- The design of the workplace
- The task
It is not enough to assess how heavy and physically demanding the work operation is. It is also important to consider the duration of the operation, how often it is repeated and whether there are possibilities for variation, breaks and rest.
Practical tips to avoid injuries
- Arrange for a workday with as much variation as possible in working positions and motions.
- Do not start the shift with the heaviest work. You body appreciates some time to warm up.
- Work as close to your body as possible.
- Do you have access to devices that can make the work easier? Use them!
- Avoid heavy lifting, particularly when in a stooping or twisted position.
- When lifting a heavy object, seek help from colleagues or use lifting devices.
- The ideal lift height is hip height. Lifts from the floor or at/over shoulder height places more strain on your body.
- If you perform work at above shoulder height, get higher, or apply an extension to the shaft to allow your arms to work below shoulder height.
- Repetitive work? Take turns using each hand, take short breaks, bend and stretch or go for a short walk.
- Be physically active in your spare time. This will enable your body to better handle the strain.
- Arrange for a working situation with as much variation as possible in working positions and motions
Refer to the Norwegian Labour Inspection Authority's web pages:
- Regulation of the performance of work (in Norwegian)
- The Workplace Regulation (in Norwegian)
- Regulation of organisation, management and partaking (in Norwegian)