Guide
OCRA vs NIOSH vs REBA: the complete guide
What each method measures, when it is the right choice, the data it needs and how to read its results — side by side.
Why pushing and pulling need their own method
A lifting method looks at a vertical load. A trolley is moved by a horizontal force, first to get it going and then to keep it moving, and that force depends on the load, the wheels, the floor and the distance. Pushing and pulling need their own measurements and their own limits.
75%
of women find the design-goal values of the Snook & Ciriello tables acceptable (Liberty Mutual tables, adapted by T. Bernard), which makes them a conservative target for a mixed workforce.
Snook & Ciriello, Ergonomics 34(9), 19912 forces
initial, to overcome inertia, and sustained, to keep the load moving, each with its own limit.
Snook & Ciriello, Ergonomics 34(9), 19912 methods
in ISO 11228-2, a psychophysical screening and an in-depth physiological and biomechanical procedure.
ISO 11228-2, Pushing and pulling0.85
the Movement Index up to which a task is green in the three-zone reading of Method 2, which many guidelines also apply to Method 1.
ISO 11228-2, risk zonesFrom chapters 3 and 4
Which ISO 11228-2 method do you need?
Answer up to four questions about the push or pull task. You get the method the guide recommends, with the reason behind it.
Question 1 of 4
Is this the first assessment of the task?
Question 2 of 4
Does the checklist flag many critical factors, or is the Movement Index above the limit?
Question 3 of 4
Do you need a biomechanical demonstration, for example of the load on the lower back?
Question 4 of 4
Is the load carried by hand rather than rolled?
Your result
Use
If nobody pushes, pulls or carries a load, ISO 11228-2 does not apply. Check the task for lifting (NIOSH) or repetitive work (OCRA).
Inside the guide
What ISO 11228-2 covers
The scope of the standard, initial and sustained force, and why pushing beats pulling.
The Snook & Ciriello tables
What the design values mean, the inputs you need, out-of-range cells and mixed populations.
Method 1: the screening
The four steps, measuring force with a dynamometer and computing the Movement Index.
Method 2: the in-depth assessment
Base force, the reduction for distance and frequency, lumbar compression and the three risk zones.
Assessing push and pull in practice
Weighted representative distance, the most common mistakes and how to lower the force.
Excerpt · Chapter 1
What ISO 11228-2 covers
ISO 11228-2 covers whole-body pushing and pulling by one person, with both hands, while standing or walking, applying a smooth and controlled force to an object in front of them. Trolleys, roll containers, pallet trucks and carts are the typical cases.
Two forces, two limits
Every push or pull task involves two different forces, and each has its own limit.
| Criterion | Initial force | Sustained force |
|---|---|---|
| What it does | Overcomes inertia and gets the load moving | Keeps the load moving once it has started |
| When it acts | At the start, and at every restart | Throughout the travel, at a steadier level |
| What raises it | Load, worn or small wheels, soft or uneven floors | Load, rolling resistance, slopes |
Both have to be measured and compared with their own acceptable value. A task can pass on sustained force and fail on initial force, typically when a heavy trolley is stopped and restarted many times per shift.
What drives the risk
- The force itself, initial and sustained.
- Frequency: how many times per minute, hour or shift the task is repeated.
- Distance: how far the load travels each time.
- Hand height: where the hands apply the force.
- Posture and floor: the trunk position, the footing and the condition of the floor.
Pushing is usually better than pulling
In most situations pushing is preferable to pulling. When pushing:
- the posture is more upright;
- the body recruits more efficient muscle groups;
- the operator sees where the load is going.
Pulling remains the right choice in specific cases, such as getting a load over a step or holding it back on a slope. Its cost is a rotated posture that overloads the shoulder and the lower back, so it should be the exception in the design of a route, not the rule.
Where it sits in the ISO 11228 series
| Task | Standard | Typical method |
|---|---|---|
| Lifting and lowering | ISO 11228-1 | NIOSH Lifting Equation |
| Carrying | ISO 11228-1 | Cumulative mass limits, or the Snook & Ciriello carrying tables |
| Pushing and pulling | ISO 11228-2 | Snook & Ciriello tables |
| Repetitive work of the upper limbs | ISO 11228-3 | OCRA |
Written for the people who move loads on wheels
HSE
HSE managers assessing trolleys, pallet trucks and carts in logistics and production areas.
Ergonomics
Ergonomists who need a clear path from a quick screening to a full ISO 11228-2 assessment.
Industrial engineering
Engineers choosing wheels, floors and routes who need to know what lowers the force.
Frequently asked questions about pushing and pulling
Which standard covers pushing and pulling?
ISO 11228-2, part 2 of the ISO 11228 series on manual handling. It covers whole-body pushing and pulling by one person, with both hands, standing or walking, applying a smooth controlled force to an object in front of them. It offers two methods: a psychophysical screening based on the Snook & Ciriello tables and an in-depth physiological and biomechanical procedure.
What is the difference between initial and sustained force?
Initial force is the force needed at the start to overcome inertia and get the load moving. Sustained force is the force needed to keep it moving once it has started. The Snook & Ciriello tables give a separate acceptable value for each, so both have to be measured and compared.
What is the Movement Index in a push-pull assessment?
The Movement Index is the ratio between the force measured on the task and the acceptable force from the Snook & Ciriello tables, computed separately for initial and sustained force. Up to 1.00 the force is within the acceptable limit. In the three-zone reading recommended by many guidelines, up to 0.85 is green, above 0.85 and up to 1.00 is yellow, borderline, and above 1.00 is red.
Is pushing better than pulling?
In most situations, yes. Pushing allows a more upright posture, recruits more efficient muscle groups and gives better forward visibility. Pulling is appropriate in specific cases, such as getting over a step or holding a load back on a slope, but it brings rotated postures that overload the shoulder and the lower back.
Which limits apply to a mixed male and female workforce?
The female limits. When the people exposed to a push or pull task are both men and women, the assessment uses the female reference values because they are more conservative. Limits for one sex are used only when the exposed population is entirely of that sex.
What does OR mean in the Snook tables?
OR stands for out of range. It marks combinations of frequency and distance outside the data the tables are based on. The tables give no value for those cells, and you should not extrapolate one without a specific methodological justification.