What the distinction fixes
Two questions, and they have different answers:
A static load is a mass at rest on the product. The measurement is straightforward: put the mass on, see whether the structure holds, and for how long.
A dynamic load is a mass in motion — landing, dropping, swinging, or being arrested by the frame. The force at the moment of arrest is larger than the mass at rest, sometimes by a great deal, and it depends on how far the mass fell and how abruptly it stopped.
A single kilogram figure on a listing is therefore incomplete until you know which of the two it answers.
What it does not promise
Neither figure promises the other. A static rating tells you nothing about a drop, and a dynamic rating for one drop height tells you nothing about a greater one.
Neither promises repetition. A structure that survives one application of a load has not thereby been shown to survive a thousand — which is what fatigue testing in a named standard is for, and what a bare declaration does not cover.
And neither promises anything about the weakest link elsewhere. A pull-up bar’s own rating says nothing about the doorway it braces against, and a rack’s rating says nothing about the bolts and the floor beneath it.
What it works with
It works with the drop height a maker publishes where one exists — on plyo boxes and trampolines it is the figure that makes the rating meaningful.
It works with the mounting instructions, because on anchored equipment the fixing and the substrate carry the dynamic case as much as the frame does.
And it works with any test reference, which is where a figure stops being a declaration: a standard names the method, and the method names the case.
How we read it on this site
Every load figure on this site is reported with the case the maker stated — static, dynamic, or unstated. Where a maker gives only one number for a product that is plainly used dynamically, the page says exactly that, and does not convert, scale or interpret it.
Nothing here derives a dynamic rating from a static one. The arithmetic to do it exists; the inputs a listing gives are not enough to run it, and a number produced that way would be ours rather than the maker’s.
Questions readers send in about this
How much bigger is a dynamic load than a static one?
There is no general figure, and this site will not print one. It depends on the mass, the drop, the surface and how the load is arrested — which is the reason engineers test rather than calculate it from a rule of thumb, and the reason a page here reports which case a maker measured instead of converting between them.
Which products most often quote a static figure for a dynamic job?
Plyometric boxes are the clearest case: a box is quoted at a resting mass and then jumped onto. Trampolines, balance boards and dip stations sit in similar territory. Where a maker specifies dynamic, the page says so, because on those shelves it is the rarer and more useful statement.
If a listing says nothing, which should I assume?
Neither — assuming is the failure. A page here records that the maker does not specify, and that unresolved state is the honest reading of the listing. What follows from it belongs to the maker’s instructions.
Last reviewed 20 September 2026