Tuck those hips under!
I've blogged before about gluteal muscles being the root of most people's problems and for those who have been assessed and treated by me will have no doubt been given gluteal strengthening exercises to perform.
http://mikestampphysio.wixsite.com/mikestampphysio/single-post/2016/10/11/Lets-get-to-the-bottom-of-this Coming from a running background, I see all to often particularly when people are getting fatigued; they start to lean forward, almost hunched over, their head is leading and their backside is trailing. This is not just a forward lean, their pelvis is tilted. In the image above, you can see what we term "pelvic neutral" (good posture) and anterior and posterior pelvic tilt. Most runners who adopt this forward lean have an anterior pelvic tilt. What does this mean to you and me? if you look at the picture of the guy with anterior pelvic tilt, you see his back is arched, his backside is sticking out, as is his stomach. No only is this giving us a series of muscle imbalances, but this is going to lead to a host of potential other problems, namely; low back pain. The first image shows which muscles are not working correctly in order for us to end up in anterior pelvic tilt. See my previous blog about muscle imbalance:
http://mikestampphysio.wixsite.com/mikestampphysio/single-post/2016/10/31/Pain-and-muscle-imbalance
As you can see, we most likely have weakened abdominals, gluteals and hamstrings and over-active hip flexors and back extensors. So we have to strengthen the weak muscles and stretch the over-active muscles. Now just going out and do ab crunches or sit ups won't cut it because you are most likely to increase that anterior pelvic tilt with your technique and only activate your upper abdominals, what we need to target is your lower abdominals. Also, going out and doing some squats to strengthen your gluteals will, most likely with a poor technique increase this pelvic tilt and make your problem worse.. This is way beyond someone saying to you: "correct your posture" this is retraining a most lilely chronic habit and muscle imbalance.