Men in general tend to struggle more with these types of poses, due to tight a pelvic region and tight butts; not to say this doesn't include women, but in my experience (myself included)- its the male form that have these types of restrictions.
This week, i have been trying a new exercise that really has helped in creating more space in an area i tend to ignore when it comes to daily Asana practice. Whilst sitting on my sofa, with a 'TV dinner' i have seated myself in Baddha Konasana, to help free my hips from the daily sentence they endure of office life. For those who do not practice yoga, (and shame on you) this is basically sitting with your feet together, hips open wide and spine straight.
The following suggestion is not rocket science, and its been suggested to me and probably to you more than once or twice (or three times, but who's counting?). This simple method can really help - and you wont feel guilty when slumped on the sofa watching a movie, (my cuts this week: Baz Lhurman's Australia and Aronofsky's, The Wrestler) or your favourite TV show.
Baddha Konasana = Bound Angle Pose
I suggest to stay in the pose for no longer than it feels comfortable - i have been managing 30 mins at a time before it feels like im going to split in two!
You can try this in the office (yes, people will look at you like you are weird - but who cares), in front of the TV and surfing the web. Remember to keep your spine straight, not to push down on your knees to try and widen your hips - just let gravity do its thing!