I don't think its ageist to expect your crew to be able to open the door should the power assist fail in an emergency, nor for them to be able to hold a slide if necessary. 70 year old crew is simply unsafe. This is a case of political correctness gone loopy. By the same rational it simply isn't safe to have crew who are so obese that they can not fit into a crew seat and can barely squeeze down the aisle, let alone bend over to engage a girt bar on a 737...