As a pianist with my very own pair of Musculus Palmaris Longus (PL) structures, I find this research most fascinating:
Notice that even though the PL is usually considered to have no impact on grip strength among most people, the paper claims:
Moreover, the changes in differences between the dominant and non-dominant hand before and after exertion seem to suggest that presence of Musculus PL may result in more evenly balanced muscle exhaustion specifically among keyboard musicians.
As is typically the case in such studies, the small N requires caution. Nevertheless, both the described methodologies and the conclusions are quite fascinating for anyone who has ever done a long concert----or who in their youth insisted on playing Chopin’s Waltz in D-flat major in under a minute just to see if it could actually be done. And because it was a fun way to pick up girls at the sorority houses which had those huge concert grand pianos. (That’s another old guy story for @Dan_Eastwood and @Michael_Callen.)