What is Ape Index?

Ape index is the measurement of reach to height disproportion. An average human has a reach (arm span, wingspan), which is roughly equal to the height of the individual, this is proportionate reach and height.

A large ape index signifies a reach which is disproportionately longer than the height. Conversely, a negative ape index means a disproportionately shorter reach for the given height.

But why is it called "ape" index?

That's because the measurement was popularized by the rock-climbing community, where the activity is close to the brachiating apes, who have disproportionately long arms. The concept of comparing reach to height itself is not new.

How to measure ape index

Ape index can either be expressed as the ratio of reach to height or as the difference between reach and height:

Example: A person with a height of 180 cm and a reach of 187 cm has an ape index of 1.038888888888889 (187 divided by 180) or 7 cm (187 minus 180).

While a unitless ratio is "universal" in nature, the involvement of decimals can make it hard for humans to mentally picture the actual value. Making use of centimeters to express the difference gives a more tangible picture. Use of inches will also result in significant decimals, so it is a good idea to go with centimeters.

What is the significance of ape index in combat sports?

So, what is the significance of having a positive ape index? Does it have any impact on performance?

Ape index, just like any other physical attribute, is just an indication of potential not a guarantee of any kind.

A person with a positive ape index will have an unexpected reach — the higher the value, the longer the unexpected reach and vice-versa. That's all there is to ape index.

Imagine you have fought or sparred with regular fighters with the average ±3 cm ape index all your life. From all this experience, you develop a relation about reach with respect to height.

And one day you meet someone with a +33 cm ape index. This person will be able to tag you from distances, which should have been safe from your understanding. This element of confusion is what makes ape index a potential positive factor in the ability to win fights. Whether the fighter is able to make use of this attribute or not, is entirely up to them, just as is the case with other attributes like height, power, speed etc.

What about those with a negative ape index?

Those with a negative ape index may be able to land unexpected effective punches in the closer range.

Is there any relation between ape index and performance?

There may be, but as mentioned earlier, it is not a guarantee but an indication of potential. Let's take a look at some examples from boxing and MMA.

It can be observed that many of the best boxers and MMA fighters of all time have/had a positive ape index. However, some of them also have/had a negative ape index.

Conclusion

A large ape index, can be a definite success factor in combat sports if one masters how to use it to one's advantage. A negative ape index can not only be overcome with other positive attributes but can also be used to one's advantage.