Yes but when I jump off two feet, the right side of my abs hurts like hell, like it's being put under a great stretch stress... I just am not flexible to do that and trust me, that affects the hip extension. It's not only the "traditional" hip flexors that stop the hip extension in my opinion. I have no idea about what the abs do movement wise (I think they're hip flexors as well, I don't know and I don't care) - I know I need to get better at this.