I do accept that there is pressure on men to conform to a muscular, youthful stereotype. It's an image that's used to market goods and services to both men and women. However, imho, this image is less pervasive than those depicting women as highly sexualised with unrealistic body proportions (photoshopped much of the time.)
I do see fewer men spending time and money on trying to achieve these "looks" than I do women trying to achieve the hairless, large busted, youthful, long-legged, scantily clothed images portrayed of women though. I also don't think women have the same expectations that real life men should live up to these unrealistic standards. However, I believe many men do expect their girlfriends and wives to at least try and look as "fit" and like the images in marketing as possible.
Also, the message they two types of images send are quite different. The sexualised, objectified images of women underpin the concept of women and femininity as decorative, passive and sexually available to men. The message accompanying images of "buff" males is one of hypermasculinity - aspire to be strong, commanding, powerful and dominant. Even though the image portrayed may be nigh on impossible achieve, it doesn't convey a negative, passive, objectified version of masculinity. That's an important difference I think.
These clever "Men Ups" show just how very different poses and stylising of women and men in marketing are. You can't really compare.