What the document fixes
EN ISO 20957 is a multi-part standard for stationary training equipment. Part 1 carries the general safety requirements and test methods that apply to everything in scope; the later parts add requirements specific to one kind of machine — strength training equipment, treadmills, rowing machines, exercise bikes, steppers and the rest. A maker citing the standard normally names both: the general part and the part matching the machine.
What the parts fix is construction and behaviour under test: stability, the absence of accessible shear and crush points, the strength of load-bearing parts, the resistance of adjustment mechanisms to unintended release, the durability of the whole assembly across a defined number of cycles, and the marking and instructions the product must arrive with.
The other thing the document fixes is the class of use. Class H is home equipment. Class S is equipment for supervised environments. Class I adds an accuracy requirement on displayed values — the figure a console shows has to be within a stated tolerance of the real one. A class letter is a statement about the duty the machine was tested for, and reading it as a ranking is the single most common mistake made with it.
What it does not promise
It does not promise that a machine will hold a particular load in a particular room. The test is run on a sample, on a rig, to a defined method; your machine is a different unit, on your floor, under your bar.
It does not promise anything about how a machine is used. Every part of the standard assumes the instructions are followed and the adjustments are made as documented. Where a rack’s safeties are set too low or a treadmill’s belt has never been lubricated, no class letter has anything to say.
It does not rank makers. Two machines of the same class have met the same requirements for the same intended use, which is precisely as far as the comparison goes.
And it does not cover most of the small gear in this catalogue at all. A lifting belt, a resistance band, a foam roller and a set of chalk are outside its scope, and a listing that waves the number over them is citing a document that does not describe them.
What it works with
The standard sits beside, and does not replace, the maker’s own figures. A published maximum user weight, a maximum total load, a motor rating and a running-surface dimension are all the manufacturer’s statements; where a machine is tested to EN ISO 20957 those figures are what the test was run against, which is the useful thing the citation adds.
It also sits beside the CE marking, which on this equipment generally follows from other legislation entirely and is not itself evidence of this test having been performed. A machine can be CE marked and never have seen this standard.
How we read it on this site
Where a listing cites the standard, its part number and its class, the page reports all three exactly as published and names the source. Where a listing cites only “EN 957” — the earlier European designation this document replaced — the page says so rather than silently modernising it, because the two are not interchangeable and the transition ran for years with both on the shelf.
Where a listing cites nothing, the page says the maker publishes no test reference, and reports the maker’s own load figure for what it is: a statement, not a test result.
Questions readers send in about this
Does EN ISO 20957 certification mean a machine is safe?
No. It records that a sample met construction and test requirements defined in the document, for a stated class of use. It says nothing about a particular session, a particular load or a particular person, and nothing on this site treats it as though it did.
What is the difference between class H, S, I and the rest?
The classes describe the intended use, not the quality. Class H is equipment intended for home use; class S covers equipment for supervised settings such as studios and clubs; class I designates equipment with an additional accuracy requirement on its displayed values. A class H machine is not a worse machine than a class S one — it is a machine built and tested for a different duty.
Why do so few listings mention it?
Because citing it is voluntary for most of this equipment, and testing costs money. A maker that has had a machine tested usually says so, often with the class and the part number of the standard. A maker that has not simply publishes its own load figure instead, which is a different kind of claim entirely.
Last reviewed 20 September 2026