{{Short description|Ratio of arm span to height}} [[File:Da Vinci Vitruve Luc Viatour.jpg|thumb|right|''Vitruvian Man'' c. 1492 by Leonardo da Vinci. Based on proportions identified by Vitruvius, the drawing shows a man where the arm span is equal to the height, giving an ape index of 1.]]
'''Ape index''', '''ape factor''',<ref name="McIver1992p5D">{{cite news | last = McIver | first = Kelly | date = September 8, 1992 | title = Rock climb jargon often tough to scale | work = Eugene Register-Guard | page = 5D | url = https://news.google.com/newspapers?id=XHwVAAAAIBAJ&sjid=_usDAAAAIBAJ&pg=4969,1811872&dq=ape-factor+climbing | access-date = September 2, 2009 | archive-date = February 27, 2022 | archive-url = https://web.archive.org/web/20220227165214/https://news.google.com/newspapers?id=XHwVAAAAIBAJ&sjid=_usDAAAAIBAJ&pg=4969,1811872&dq=ape-factor+climbing | url-status = dead }}</ref> or '''gorilla index''' is slang or jargon used to describe a measure of the ratio of an individual's arm span relative to their height. A typical ratio is 1, as identified by the Roman writer, architect and engineer Vitruvius prior to 15 BC. Vitruvius noted that a "well made man" has an arm span equal to his height, as exemplified in Leonardo da Vinci's c. 1492 drawing, the ''Vitruvian Man''.<ref>{{Harvnb|Pheasant|1996|p=7}}.</ref> In rock climbing it is believed that an ape index greater than one, where the arm span is greater than the height, provides for a competitive advantage, and some climbers have expressed the belief that exercise can result in an improved ratio, although this view is somewhat controversial.<ref name="Sagar2001p144">{{Harvnb|Sagar|2001|p=144}}.</ref>
== Computation ==
The ape index is usually defined as the ratio of arm span to height. However, an alternative approach is arm span minus height with the result being positive, 0 or negative. Unlike the dimensionless ratio, this calculation produces a numeric value in the units of measurement used to represent the height and arm span.
== Significance in competition climbing ==
Multiple studies have been conducted into the effect of physiological factors, such as anthropometry and flexibility, in determining rock climbing ability, particularly in the area of competition climbing, which is an Olympic sport. A number of these have included the ape index as one of the variables. However, the results have been mixed.
One study found that "untrainable" physical factors, including the ape index, were not necessarily predictors of climbing ability, despite a general tendency identified in previous studies for elite athletes in the sport to share these characteristics.<ref>{{Harvnb|Mermier|Janot|Parker|Swan|2000|pp=364–365}}</ref> {{clarify span|text=This was supported by a later study that also found that the ape index was not statistically relevant|explain="statistically relevant" is not a common term in statistics. The term "statistically significant" exists, but "not statistically significant" is absolutely not evidence that something does not exist; if anything it rather means we can't conclude anything. So if "statistically significant" is what is meant here, we can't say it's "supported by a later study".|date=December 2025}}. However, the authors of this second study noted that the findings may have been due to the low variability in the index between the climbers, who all had significantly higher ape indices than those found in the control group. Thus they left open the possibility that the ape index may be more significant when there is a greater degree of equivalence between the other traits under consideration.<ref>{{Harvnb|Watts|Joubert|Lish|Mast|2003|p=423}}.</ref> Successful professional climbers such as Brooke Raboutou and Lynn Hill have negative ape indices.<ref>{{Cite web |title=La Sportiva Ambassador |url=https://www.lasportivausa.com/brooke-raboutou |access-date=January 14, 2026}}</ref><ref>{{Cite web |last=Lambert |first=Katie |date=May 30, 2023 |title=Why "I'm Too Short" Isn't a Worthwhile Excuse |url=https://www.climbing.com/culture-climbing/does-height-matter-climbing/ |access-date=January 14, 2026 |website=Climbing}}</ref>
Countering these studies are other works that have identified the ape index as a significant (or potentially significant) factor. A 2001 study comparing teenage male and female competition climbers noted that performance differences between the genders could be explained by several factors, one of which was the lower ape index found in the female competition climbers.<ref>{{Harvnb|Moss|Kunz|Adams|Berning|2001}}.</ref> Similarly, in a later work it was found that the ape index was statistically significant, and thus determined that it was one of several variables that provided the highest diagnostic value in the prediction of climbing performance.<ref name="Magiera12007pp96-97">{{cite journal | last1 = Magiera | first1 = Artur | last2 = Ryguła | first2 = Igor | year = 2007 | title = Biometric Model and Classification Functions in Sport Climbing | journal = Journal of Human Kinetics | volume = 18 | pages = 96–97 }}</ref>
== Other sports == The term was first coined by Frisbee throwers at UC Berkeley in 1975. {{Citation needed|date=January 2026}}
It has been noted that swimmers tend to have longer arms in relation to their body size.<ref>{{Harvnb|Lavoie|Montpetit|1986|p=168}}.</ref> A notable example is Michael Phelps whose arm span is {{cvt|10|cm|in}} greater than his height, giving him an index of 1.052.<ref>{{Cite web|url=https://sportsgratitude.com/michael-phelps-ape-index/|title=Michael Phelps APE Index|date=3 September 2021 |language=en|access-date=2022-02-27}}</ref>
There is evidence to support that having a higher index will be beneficial to a football goalkeeper {{Citation needed|reason=What evidence|date=March 2018}}. It can also compensate for being shorter than the recommended norm for a professional goalkeeper{{Citation needed|reason=Can it? Cite! Don't assume.|date=March 2018}}. Iker Casillas and Jorge Campos are examples of shorter goalkeepers who possess a higher than average index.
In basketball, a higher index helps with defense, especially in contesting shots and intercepting passes {{Citation needed|reason=Does it? Show research. Don't make your own assumptions. Is it the ape index? Is it they are naturally more skilled? The Epstein book does not assert this claim. If it does, reference it directly.|date=March 2018}}. It also helps with rebounding, and with dribbling, passing, and shooting when being guarded closely by opponents. David Epstein in his book ''The Sports Gene'' devoted a chapter to "The Vitruvian NBA Player" and therein noted "The average arm-span-to-height ratio [i.e., ape index] of an NBA player is 1.063."<ref name="Epstein2014">{{cite book|author=David Epstein|title=The Sports Gene: Inside the Science of Extraordinary Athletic Performance|url=https://books.google.com/books?id=00eKDQAAQBAJ|date=29 April 2014|publisher=Penguin Publishing Group|isbn=978-1-61723-012-7|pages=134–135}}</ref> Having an ape index of less than 1 is very rare among NBA players; only two players in the NBA 2010–11 season had one.<ref name=Epstein2014 /> One notable NBA player with an ape index below 1 is Desmond Bane, whose wingspan of {{cvt|6|ft|4|in|cm}} is less than his {{cvt|6|ft|5|in|cm}} height; he has been nicknamed "T-Rex" for this reason.<ref>{{Cite news |last=Vorkunov |first=Mike |title=We're talking about wingspan?! Desmond Bane was overlooked, now he and Ja Morant are leading a Memphis revival |url=https://www.nytimes.com/athletic/3049343/2022/01/06/were-talking-about-wingspan-desmond-bane-was-overlooked-now-he-and-ja-morant-are-leading-a-memphis-revival/ |access-date=2024-03-08 |website=The Athletic |language=en}}</ref> Despite this perceived deficiency, Bane has become a quality player since being selected 30th overall by the Memphis Grizzlies in the 2020 NBA draft out of TCU.
In combat sports, such as boxing and mixed martial arts, having a higher index is often perceived to be beneficial. Fighters such as Jon Jones (whose arm span is {{cvt|21|cm|in}} greater than his height) and Conor McGregor have a longer arm span than most of their opponents. Sergei Pavlovich is believed to be the active UFC fighter with largest Ape index of 1.115, with a {{cvt|191|cm|ftin}} height and {{cvt|213|cm|ftin}} reach.<ref>{{Cite web |last=J |first=Jeff |date=2021-03-17 |title=How Much Does Height And Reach Matter In Combat Sports? |url=https://mmachannel.com/how-much-does-height-and-reach-matter-in-combat-sports/ |access-date=2024-08-30 |website=MMA Channel |language=en-US}}</ref> This potentially allows them to use their arm span to hit their opponents, whereas their opponents could not hit them. They often use this in their game plan, by keeping their distance, allowing them to cover up (as longer arms allow for a greater area of protection around the upper body) or use it to counter punch them.<ref>{{Cite web|url=http://www.ufc.com/event/UFC182/printFightCard|title=Print Fight Card {{!}} UFC 182 Jones vs. Cormier|website=www.ufc.com|language=en|access-date=2017-06-16}}</ref><ref>{{Citation|last=MindSmash|title=Conor McGregor's Counter Punch {{!}} Breakdown|date=2017-01-23|url=https://www.youtube.com/watch?v=9Fzc_kSFO9A|access-date=2017-06-16}}</ref> However, research has shown that the ape index cannot predict who wins or loses MMA bouts, an individual's divisional ranking, or whether or not they are successful in their technique use.<ref>{{Cite journal |url=https://content.sciendo.com/view/journals/ssr/25/5-6/article-p334.xml |title=Does Stature or Wingspan Length Have a Positive Effect on Competitor Rankings or Attainment of World Title Bouts in International and Elite Mixed Martial Arts? |last=Kirk |first=Christopher |journal= Sport Science Review |volume=25 |issue=5–6 |date=2016 |pages=334–349 |doi=10.1515/ssr-2016-0018 |s2cid=59027630 |access-date=2018-10-03 |archive-url=https://web.archive.org/web/20181003181833/https://content.sciendo.com/view/journals/ssr/25/5-6/article-p334.xml |archive-date=2018-10-03 |url-status=dead |url-access=subscription }}</ref><ref>{{Cite journal|url=http://casopisi.junis.ni.ac.rs/index.php/FUPhysEdSport/article/view/2070|title=The Influence of Age and Anthropometric Variables on Winning and Losing in Professional Mixed Martial Arts|journal=Facta Universitatis, Series: Physical Education and Sport|date=8 November 2016|pages=227–236|last1=Kirk|first1=Christopher}}</ref><ref>{{cite journal |url=https://www.researchgate.net/publication/325180899 |title=Does Anthropometry Influence Technical Factors in Professional Mixed Martial Arts? |last=Kirk |first=Christopher |journal=Human Movement |volume=19 |number=2 |date=May 2018 |doi=10.5114/hm.2018.74059|doi-access=free }}</ref>
Small ape indices can also be beneficial. For example, in the bench press, a lifter with a shorter ape index must move the weight a shorter relative distance to complete the lift when compared to a lifter with a longer ape index. In contrast, a long ape index is an advantage in the deadlift, where longer ape indices reduce the range of motion required to complete the lift.<ref>{{Cite web |title=Is a Bench Press Affected by Arm Length? |url=https://www.livestrong.com/article/458669-is-a-bench-press-affected-by-arm-length/ |access-date=2024-03-08 |website=LIVESTRONG.COM |language=en}}</ref>
==See also== * Ajanubahu * Intermembral index
==Notes== {{reflist|2}}
==References== {{refbegin}} *{{cite journal | doi = 10.2165/00007256-198603030-00002 | last1 = Lavoie | first1 = Jean-Marc | last2 = Montpetit | first2 = Richard R. | title = Applied physiology of swimming | journal = Sports Medicine | volume = 3 | issue = 3 | date = May 1986 | pages = 165–89 | pmid = 3520747 | s2cid = 8776981 }} *{{cite journal | last1 = Mermier | first1 = Christine | last2 = Janot | first2 = Jeffrey | last3 = Parker | first3 = Daryl | last4 = Swan | first4 = Jacob G. | title = Physiological and anthropometric determinants of sport climbing performance | journal = British Journal of Sports Medicine | volume = 34 | issue = 5 | date = October 2000 | pages = 359–365 | doi = 10.1136/bjsm.34.5.359 | pmid = 11049146 | pmc = 1756253}} *{{cite journal | last1 = Moss | first1 = C. | last2 = Kunz | first2 = M. | last3 = Adams | first3 = K. J. | last4 = Berning | first4 = J. M. | last5 = Sevene-Adams | first5 = P. G. | last6 = Debeliso | first6 = M. | title = A comparison of male and female teenage sport rock climbers from a high school climbing league | journal = Medicine and Science in Sports and Exercise | volume = 33 | issue = Supplement 1, issue 5 | date = May 2001 | page = S247 | doi=10.1097/00005768-200105001-01386| doi-access = free }} *{{cite book | last = Pheasant | first = Stephen | title = Bodyspace: anthropometry, ergonomics, and the design of work | publisher = Taylor & Francis | year = 1996 | edition = 2nd | location = London | isbn = 978-0-7484-0067-6 }} *{{cite book | last = Sagar | first = Heather Reynolds | title = Climbing your best: training to maximize your performance | publisher = Stackpole Books | year = 2001 | location = Mechanicsburg, PA | isbn = 978-0-8117-2735-8 }} *{{cite journal | last1 = Watts | first1 = Phil | last2 = Joubert | first2 = Lanae | last3 = Lish | first3 = Aaron | last4 = Mast | first4 = J. D. | last5 = Wilkins | first5 = B. | title = Anthropometry of young competitive sport rock climbers | journal = British Journal of Sports Medicine | volume = 37 | issue = 5 | date = October 2003 | pages = 420–424 | doi = 10.1136/bjsm.37.5.420 | pmid = 14514533 | pmc = 1751349}} {{refend}}
==External links== *[http://www.ape-index.com: Ape Index Calculator] *[https://web.archive.org/web/20141017034049/http://www.seriousgoalkeeping.net/ApeIndex.aspx Is height important for a soccer goalkeeper?] {{Climbing navbox}} {{DEFAULTSORT:Ape Index}} Category:Climbing and health Category:Anthropometry