by Brad

February 8, 2021

What Is Ape Index

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Here, the focus in a particular instance of climbing slang is referred to as the Ape Index. This term is well known. 

With a proper understanding of it, you will be able to recognize your limitations and strengths with respect to climbing and likewise activities.

How to Measure the Ape Index and What Is It?

The Ape Index is the link ratio of your arm length to your height. To evaluate it, measure both the parameters and then calculate it by dividing the wingspan from your height or negate your height from your wingspan.

The methods are given here individually. Let's see what the outcome is. For instance, the measurements are taken, and the parameters can be swapped with yours to get your result.

What Is Ape Index and How to Measure It

1.) Negating your height off your wingspan

The formula is wingspan - height = the Ape Index

E.g., Bernice has 70 inches wingspan, and her height is 68 inches.

The height should be converted to inches or cm to get the right value. Both wingspan and height should be of the same metrics.

Applying the formula, it is 70-68 inches=2 inches Ape Index. Or take the centimeters value of both parameters to get the final result. You get 177.8 cm- 171.7 cm to get 6.1 cm ape index.

If you observe, the majority of the people have height and arm span to be same or almost same. In such a case, the value is zero irrespective of inches or centimeters. But, if the parameters vary then, the ape index has a value, just as in the above example.

2.) The ratio of your wingspan to your height  

The formula is wingspan/height.

This method gives a ratio between the climber's height and wingspan. It is not a well-known method, though, but it is simple to implement.

Taking the same parameters of Bernice, whose height is 68 inches or 171.7 cm with a 70 inches wingspan, the ape index is evaluated using the above formula.

The result is 70/68 inches=1.03 inches ape index. This indicates the wingspan is somewhat over the height, and the ratio is over 1.

The majority of the climbers possess a ratio of flat 1, implying their height and wingspan being the same. The parameters evaluated in centimeters reveal the same ratio, unlike the previous method. The primary benefit of using this method is this.

Popular Climbers and Their Ape Indexes 

Popular climbers ape index

You will see the actual value of the ape indexes of some of the most famous climbers of the world for comparison with your value of the ape index here. When the ape index is positive implying the wingspan to be larger compared to your height, it is observed that enhanced performance in climbing is related to your height.

However, it need not be the case always. This aspect will be seen further in the article. On extremes, Kai Lightner's ape index ratio is the largest, with a value of 1.09. The variation of the wingspan concerning height is 7.0. This is because Kai's arm span is 82" while the height is 75 inches.

On the contrary, Babsi Zangerl, the best climber in the female category with a height of 63.8 inches and a 63 inches wingspan, possesses a negative value of ape index ratio of 0.99 and a value of -0.8.

Amongst other famous climbers, Alex Megos and Hazel Findlay have one ape index ratio. This implies that their wingspan and height are the same. Though most well-known climbers are known to have longer arms, it adds to their benefit, as can be seen with their ape index values. Let's evaluate this aspect a little more closely.

A Positive Value of the Ape Index is Beneficial

The ape index's positive value is better for a climber when you measure two climbers' performance who have the same height but with a variant ape index ratio. When the height is the same for climbers, a positive value implies more reach, efficiency, and more comfortable climb.

The other aspect is ape index value cannot be varied through a training routine or an improvement technique. A climber can enhance the overall reach by improving flexibility, but not the ape index.

A professional climber is optimum in shape and trained correctly. All a climber can do is to improve his or her performance but can no way impact the ape index value.

A Positive Value of the Ape Index is Beneficial

The training aspects include your overall fitness level, body fat percentage, and overall strength on the grip. These factors are with respect to your bodily mass. An article on grip training, their benefits, and training methods to gain conventional grips with rice buckets was written a while.

The grip is improved by minimizing the percentage of body fat and will add to better climbing. It also provides you direct control over these aspects. There is effort involved, but the result is worth the effort.


Gorilla index or ape index or ape factor is a variable that is non-trainable. In many studies, this factor focuses on the impact of physiological aspects in rock-climbing capabilities. The outcomes are mixed.

Some of the studies reveal that there is no correlation between enhancing climbing capabilities and non-trainable aspects. A study referred to as the ape factor was not relevant. This is due to the lower variability in climbers.

Another study of 2001 reveals performance comparisons of female climbers to male teenage climbers. Many factors were considered in explaining performance differences, amongst which female climbers having a lower ape index was one.

What is Ape Index and How to Measure it

Importance of the Ape Index in Other Types of Sports:

  • From some research done, it's seen that possessing long arms to height can be a significant advantage in some other sports.
  • Long arms can enhance your swimming performance—for instance, Michael Phelps whose 10 cm/3.9 inches arm span is more than his height.
  • More player reach in boxing implies making a hit to your counterpart, maintaining sufficient distance. Short arms have difficulty as they are closer to the opponent. Conor McGregor, for instance, is a great boxer who has an impressive ape index.
  • High ape indexed goalkeepers are good in their goalkeeping than the keepers with short arms.
  • A positive value of ape index makes basketball simpler to shot interception and passing contests. This makes the basketball player good at defense naturally.

About the author 


Brad is a professional climber in the discipline of traditional climbing. He often jokes that he can get a book to read during the long climbs. Of course, it always goes well with a good cup of coffee. Drinking coffee is his safer hobby.

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