Janie, Get Your Gun

And I have no problem with units holding women entrants to the exact same fitness requirements (length and time of runs, weight carrying, no of sit-ups etc) as men.

There are reasons why a very smart/talented person of lesser fitness might be an asset to a unit, but when the issue is an elite unit like special forces, then the entrance requirements demand the best of the best, including outstanding strength, stamina and flexibility.