What it calculates
The equation reduces a starting load value according to the conditions of the task and gives the limit recommended for it. What drives the reduction is the geometry: how far the load is from the body, the height of the lift, the vertical travel, the angle of trunk twist, the quality of the grip and the frequency of lifting.
Why a single weight limit is not enough
A single figure such as "twenty-five kilograms" does not see whether the same load is lifted from knee or shoulder height, with the trunk twisted or straight, once an hour or once a minute. The equation takes these into account as separate multipliers.
How to read the result
The value produced is a design target, not a prohibition threshold. Where the actual load exceeds it, the task itself is changed: the load is split, the height adjusted, the distance shortened or an aid provided.
Its limits
The equation is not designed for one-handed lifting, two-person lifting, pushing and pulling, seated lifting or unstable loads. In those cases other methods are used.
In Optifora
The lifting assessment takes the multipliers on screen, shows the result, and recalculates the same task after improvement to place the difference side by side.