noun
going (of stairs); length (of a step)
Architectural term for the horizontal depth of a stair tread, i.e., the distance from the front to the back of a step. Also used more generally for the length of something laid horizontally.
階段の伏せ長は、通常25センチ程度が歩きやすいとされる。
A stair tread depth of about 25 centimeters is generally considered easy to walk on.
この図面では、伏せ長が明記されていない。
The tread depth is not specified in this blueprint.
蹴上げ is the vertical rise of a stair step, while 伏せ長 is the horizontal depth (going).
踏み面 is a more common term for the tread surface; 伏せ長 is a technical measurement of its depth.
Compound of 伏せ (ふせ, 'lying face down' or 'covering') and 長 (なが, 'length'), referring to the horizontal length of a laid surface. The exact historical derivation is uncertain.