If someone shoves my shoulders and stretches my rectus abdominis muscles (anterior abdominal muscles), then my stretch reflex will occur causing... O contraction of my rectus abdominis and relaxation of antagonist muscles in my back contraction of my rectus abdominis and also of antagonist muscles in my back o relaxation of my rectus abdominis and contraction of antagonist muscles in my back relaxation of my rectus abdominis and also of antagonistmuscles in my back