I say "even men" because I learned this stretch as part of prep for popping out babies years ago. It's great for loosening up the hips, opening up the pelvic stuff and stretching the back of the legs down into the feet mostly, and also the back and quads. So yeah, great for birthing babies, but also great for limbering up your core so you can be nice and loose and belly dance that bike through the tight stuff.
Stand up facing something solid,like a door jamb, or something heavy like a couch with a leg you can grab when you squat down--a door jamb is better if you have weak legs and knees and then you can use it to pull yourself back up. Have your feet shoulder width apart(can be a little further apart to allow you to stretch as needed). Squat down, butt(almost)to the ground, grab your support and lean back just enough to get your heels/feet flat on the ground. Round your back and hold for 30 seconds. You can get a stretch in your shoulders too by being far enoung away from your support so your arms are out straight when you lean back.
Just do it!
(disclaimer, if your knees are shot to crap don't do it, sorry!)