Why ape Tadej for 165 mm crank arm

Wheels of Happiness

Many attribute part of faster Pogi on shorter 165 mm.  It is one style of Pro that we should copy.

Advantages

1.  More stability

2.  Less joint stress

Mine is 170 mm.  

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Should you ape Pogi by using shorter cranks?

Wheels of Happiness Pogi seems to be leaving behind his competitors because of shorter canks - 165 mm. Could it be? I use 170 mm. Is 5 mm difference material?