Originally Posted by
surak
Physiologically it may be more comfortable, but you aren't changing your gearing range, so shorter cranks alone aren't going to make it easier to spin. You need the same cadence to go the same speed regardless of crank length.
Changing the cranks to a smaller size decreases the range of the pedal spin (a smaller circle). It will make a difference in mashing vs spinning. The power output is the same but the muscle group in extreme cases would be different.