A certain amount of openness may lead to greater reproductive success for women, whereas for men, the legs in the "splits" may be a position of with a lack of leverage, and thus weakness.
I can sit reasonably comfortably heal to heal with my knees on the ground (barefoot, or with socks on), although I suppose not everyone is able to do so. But that would indicate to me that the splits wouldn't necessarily be an anatomical impossibility. However, I've never been able to do the splits. But, it would indicate that there are some tendons that need to be stretched.
Male (and female) Gymnasts, and Martial Arts experts may get adequate stretching to be able to get into the splits.Jean-Claude Van Damme
apparently started martial arts at age 10, and took ballet at age 16. Perhaps it is easiest to achieve the flexibility to do the splits if one starts early.
There were two trucks. The one on the right appeared to be a tractor trailer, whereas the one on the left wasn't. Why is the cab clearance so tight for the tractor trailer? Anyway, it would take some extreme precision driving to back both rigs up to maintain a precise separation between the cabs. In fact, it might be much easier to drive forward, then run the video backwards, especially if there was a harness that could aid with lifting and stability for JCVD.