wow spitting up blood? i think that may be a sign of a stomach ulcer, you should get that checked. Yes i do intense abdominal training daily but i don't think its the abdominals that is causing a posture problem. It's the psoas(hip flexors) when you sit down too much or when they are overdeveloped compared to the glutes(behind), your pelvis sags in the front, which pulls the spine out of it natural position(stomach sticks out/glutes stick out). So in my case its weak/inhibited glutes. You get that from sitting down too much or if the hip flexors are too strong compared to the glutes. Spitting up blood is serious though, you should get checked up, sounds like a stomach ulcer.