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... if there were huge advantages the pro teams would have adopted it...
I'm not sure that there are massive gains to be had, rather there's no downside and there are incidental benefits: higher cadences are easier, less stress on the knees, open hip angle, and positional options.
If you find more power and are more aero, then that's a bonus.
Most of cycling would rather forswear their first born, than believe that crank length is not dependent on leg length, so it's hardly surprising there's little demand for good quality, short cranks.
I was using 160mm towards the end of this season, but they didn't get much use so the only thing I can say for certain is that it's easier to maintain a high cadence.
The particular cranks I was using had a beefy Q-factor though, so they're not going back on.
However I've tracked Mike Burrows down and he'll shorten a pair for £25, so I'm planning on getting some 7410 chopped to 145mm...