Chronic sitting will turn the front side of your body into a functionally shortened mess – never a good thing when it comes to performance or injury prevention. The region that suffers the most? Hip flexors, both the superficial and deep muscular layers.
Most people know they sit too much during the day, and they know their hips are tight as a result. So they think if something has become "short" over time, the most effective way to increase length is to stretch it, right? Wrong!
Functional trainers love this half-kneeling position, but forcing the hip into ultra-terminal extension with your shin lodged up against a wall while your spine is smashing itself into hyperextension is dumb. Not only does this position hurt (which most people perceive as a good thing), but it's ineffective at best and injurious at worst.
While putting tissues through a full range of motion and achieving terminal end range is the goal for transferable mobility, extending terminal ranges of motion by the use of compensation patterns is dangerous when you do it repetitively.
Rear Foot Elevated Hip Flexor Stretch
When you stretch you should achieve and maintain a neutral position in the joints and spine in order to isolate the tissues you're targeting. The half-kneeling position should make you achieve centrated and neutralized joint positions at the shoulders, hips, and spine.
It should also transfer these positions into useful strategies to improve the response of your rectus femoris and deep ilio-psoas group, not only a mechanical standpoint but also to "release" neurological based tone and tightness.