It takes time to build strength in the abs, so take your time and complete the move slowly rather than using momentum to lift your body. Back Arch In the past, it was recommended to keep your back flat against the floor throughout the entire movement. Now it is believed https://bookmarkity.com/story18141313/o-fato-sobre-renato-cariani-que-ningu%C3%A9m-est%C3%A1-sugerindo