Amulet Titan relies on cheap enablers like Arboreal Grazer, Amulet of Vigor, and Spelunking to set up a turn where Scapeshift or Primeval Titan takes over, so Trinisphere taxes all of that early interaction and can single-handedly blank their Amulet of Vigor plan. Force of Vigor is a clean answer to the Amulet of Vigor itself or their Urza's Saga before it fetches a free artifact, disrupting their engine at its core. Cut the slowest top-end since this matchup is about denying their explosive early turns before they can bury you in extra lands and a Primeval Titan or Cultivator Colossus; once they're established your ramp plan still races well, so keep the core Fight Rigging and Emrakul package.