Monkey index

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The monkey index or English ape index is an anthropometric measure that establishes a connection between arm span and height of a person. Although the term originated in the unscientific sport climbing scene, it can now also be found in scientific literature.

calculation

To calculate the monkey index, the body height and the arm span must be measured. The arm span is defined as the distance between the end points of the middle fingers with the arms and fingers stretched horizontally to the side.

There are two different approaches to the calculation itself:

  • The more common method used in scientific work defines the monkey index by dividing arm span by body height.
  • According to some websites devoted to climbing, the monkey index is found by subtracting by subtracting body height from the arm span.

A positive monkey index is given when the arm span exceeds the body height. This is shown in the subtraction calculation by a positive number and in the division method by a number greater than one. If the arm span is less than the body height, the subtraction calculation results in a negative number and the division method results in a number smaller than one. If the arm span and body size are the same, this results in a monkey index of zero for the subtraction method or one for the division method.

Properties of the monkey index

In adults there is a correlation between arm length and height. The average monkey index number is close to the neutral index number, which means that the arm span is almost identical to the body height. This finding is also supported by the German climber survey, which resulted in an average ape index calculated using the division method of 1.02. A study carried out on a large number of Koreans showed that the monkey index mostly deviates downwards in small adults, whereas it tends to deviate upwards in tall adults. It is therefore not surprising that athletes with extremely large arm spans and high monkey index numbers are often very tall: Examples are:

  • The discus thrower Lars Riedel with a height of 199 cm and an arm span of 210 cm (division method: 1.055)
  • The swimmer Michael Phelps with a height of 193 cm and an arm span of 204 cm (division method: 1.057)
  • The basketball player Misan Nikagbatse with a height of 192 cm and an arm span of 208 cm (division method: 1.083)

The extensive Korean study mentioned above also dealt with the change in various body dimensions - including the monkey index, but without using the term monkey index - in the course of child development in over 10,000 children and came to the conclusion that the monkey index is independent of the Gender increases with age. The scientists also found that the same tendencies apply to adolescents as to adults: older children of the same age have a higher monkey index.

Influence on climbing performance

Climbers often assume that the highest possible monkey index number has a positive effect on climbing performance. This is based on the idea that longer arms are better for the same body size, as they allow a greater reach. However, this assumption does not take into account that the leverage ratio can be less favorable with longer arms and that the range also depends on the body height itself. A taller climber can therefore have a significantly larger reach than a smaller climber with a larger monkey index despite a lower monkey index number.

Various studies showed that there is no significant correlation between the monkey index and climbing performance. Even with the maximum achievable distance between two holds on dynamic climbing moves , neither the monkey index nor the body height has a decisive influence. As far as we know today, there is no reason to assume that the monkey index number has an influence on climbing performance.

literature

  • PB Watts, LM Joubert, AK Lish, JD Mast, B. Wilkins: Anthropometry of young competitive sport rock climbers . In: British Journal of Sports Medicine . No. 37 , 2003, p. 420–424 , doi : 10.1136 / bjsm.37.5.420 (English, only abstract freely accessible without registration).
  • D.-J. Yun, D.-K. Yun, Y.-Y. Chang, S.-W. Lim, M.-K. Lee, S.-Y. Kim: Correlations among height, leg length and arm span in growing Korean children . In: Annals of Human Biology . tape 22 , no. 5 , 2005, p. 443–458 , doi : 10.1080 / 03014469500004112 (English, only abstract freely accessible without registration).

Web links

Individual evidence

  1. ↑ a b c Watts et al .: Anthropometry of young competitive sport rock climbers . In: British Journal of Sports Medicine . No. 37 , 2003, p. 420-424 , doi : 10.1136 / bjsm.37.5.420 .
  2. ^ A b c Paul Martin: An Evaluation of the Validity of Dyno Test in Climbers. In: www.trainingforclimbing.com. 2005, archived from the original on March 13, 2008 ; accessed on April 7, 2014 (English).
  3. ↑ a b Tools: Climbing Calculations. In: getbeta.com. Archived from the original on September 7, 2008 ; accessed on April 7, 2014 (English).
  4. ↑ a b c monkey index. In: Motionontherocks. August 17, 2007, accessed February 18, 2008 .
  5. ↑ a b Arm span equal to body size? In: T-Online Switzerland. Retrieved February 18, 2008 .
  6. ↑ a b Yun et al .: Correlations among height, leg length and arm span in growing Korean children . In: Annals of Human Biology . tape 22 , no. 5 , 2005, p. 443-458 , doi : 10.1080 / 03014469500004112 .
  7. ↑ Martin Geissler: Nikagbatse with awesome game at the NBA pre-draft camp. Schoenen-Dunk.de, April 23, 2004, accessed on December 13, 2014 (press release Mitteldeutscher Basketball Club by Martin Geissler).