[Nasrudith]

The flexibility at least is a play to strengths in one of the few areas where men were at a disadvantage athletically. Women on average are more flexible and their lower spines retain more juvenile flexible as it is useful for a shift in center of mass with pregnancy. Upper body strength was the male answer for "what can they do which is more impressive if they are higher mass and worse at physical flexibility"? The why may have something to do with performance peaks attracting more attention for a sport (I would have expected at least a niche for upper body strength events for women and flexibility for men) but that could also be a chicken and egg thing with culture.

There certainly is sexist baggage involving women being considered more "ornamental" though.