The antonyms for the phrase "shooting ahead of" would include lagging behind, falling behind, trailing, and bringing up the rear. These terms suggest that someone or something is not keeping up with the pace or progress of others, and could be experiencing a delay or setback. While shooting ahead of implies a sense of speed, velocity, and progress, the antonyms indicate a sense of delay, inertia, or stagnation. When used in context, they can reveal the relative position or performance of one person or thing compared to others, and can help clarify the dynamics of a race, competition, or project.