Wikipedia:Reference desk/Archives/Miscellaneous/2020 June 13

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June 13

height of kneeling

What height would a tall person (like 76-inch) be if he/she kneeled? 86.129.17.70 (talk) 20:13, 13 June 2020 (UTC)

Depends on the exact ratio between their leg length snd size of their torso. Also how erect their legs are versus bending the knees all the way back.--Khajidha (talk) 22:17, 13 June 2020 (UTC)

The mean knee height as a percentage of body height measured in a group of 89 Caucasian Australian adults aged 25–62 is given here as 30.5±1.2% Assuming a general proportionality of a person's articulation (but note that some excessively tall people have disproportionally long legs) we can estimate the height of a fully kneeling but otherwise erect adult as being 69.5% of their body height plus an extra inch or two because the knee joint is actually a bit higher than ground level – by roughly half the diameter of the leg measured around the knee, which I estimate to be about 4% of the body height, Altogether this gives an estimate of 73.5% of 76 inch = (rounded) 56 inch (142 cm). Adding two sigma = 2.4% gives a plausible upper limit of 58 inch.  --Lambiam 07:48, 14 June 2020 (UTC)

I think this is a good answer. I measured it for myself: my height is 192 cm (or 75.6 inch), and I found that while kneeling I was about 141 cm (55.5 inch). Of course it will vary from person to person, but the above seems to be a reasonable estimate. - Lindert (talk) 13:06, 14 June 2020 (UTC)

Are these figures for kneeling with thighs vertical or with the person sitting back on their haunches?--Khajidha (talk) 19:07, 14 June 2020 (UTC)

Thighs vertical (or as Lambian put it fully kneeling but otherwise erect). - Lindert (talk) 20:25, 14 June 2020 (UTC)

See, I wouldn't describe that as fully kneeling. To me, fully neeling would be sitting back on your feet. "Otherwise erect" would seem to contrast with prostrating your upper body.--Khajidha (talk) 20:38, 14 June 2020 (UTC)

Yes that's understandable. I don't know what the OP was specifically asking for, but the calculation above simply subtracts the height of the knees from the standing height, and that seems to also be the sense in which Da Vinci describes it. - Lindert (talk) 20:43, 14 June 2020 (UTC)

So if a person who is 76-inches tall had kneeled down, he or she would be about half the height (38 inches)?86.129.17.70 (talk) 11:37, 14 June 2020 (UTC)

No, that is not what I said. I wrote 56 inches, which is a lot more than half the height. It they were sitting upright on the floor (with stretched legs), they would reach to about half their standing height.  --Lambiam 12:47, 14 June 2020 (UTC)

That clever chap Leonardo da Vinci, a student of the equally clever but much older Vitruvius (you may recall the Vitruvian Man), wrote that "if a man kneels he will diminish by a quarter part of his height". See Recto: The proportions of a standing, kneeling and sitting man. Verso: Notes on human proportion c.1490 So by that rule, a man of 76 inches (6 feet) would be 57 inches (4 feet and 9 inches) tall when kneeling. That's an exact median of Lambiam's admirable but rather more complex calculations above. Alansplodge (talk) 12:36, 14 June 2020 (UTC)

Take the actor Liam Neeson, for example. Here is a screenshot of the first Star Wars prequel film of him kneeling to 8-9 year old Jake Lloyd who is about 39-41.6 inches tall. 86.129.17.70 (talk) 21:47, 14 June 2020 (UTC)

Liam Neeson's is reported here as having stated his height in 1991 as 6 feet and 4 inches (76 inches). In the screenshot he is not kneeling fully (you can see the tip of his right shoe protruding from under the robe) and also not otherwise erect; he is leaning forward with his right arm on his right knee.  --Lambiam 07:00, 15 June 2020 (UTC)

So if he's not kneeling fully and instead leaning forward, does that it mean he is about the same height as the child? 86.129.17.70 (talk) 21:31, 15 June 2020 (UTC)

You can see for yourself in the screenshot that the standing child reaches a bit higher than the half kneeling and forward-leaning adult.  --Lambiam 13:59, 16 June 2020 (UTC)

76 ÷ 2 = 38. 76 - 20 = 56. 86.129.17.70 (talk) 19:27, 16 June 2020 (UTC)

• I am about 75 inches. I took a tape measure into the bathroom and knelt by the mirror. (Ow my knees.) About 55 inches. I could get a better answer if someone else were to hold and read the tape, but the cats are useless for this sort of thing. — Now you know something more about me. —Tamfang (talk) 00:18, 19 June 2020 (UTC)

I am about 60 inches. I took a tape measure and knelt. About 35-42 inches. Calculator-60 ÷ 1.7 = 35.29411765. 86.129.17.70 (talk) 21:27, 19 June 2020 (UTC)