Obby: Pump Up Your Muscles is a strength-building obby game set inside a prison gym. Start as a skinny rookie, train with push-ups, sit-ups, and pull-ups, and grow stronger with every rep. Build your body, improve your power, and rise through the prison gym ranks. The game focuses on training progress, simple actions, and becoming stronger step by step. Play the Obby: Pump Up Your Muscles game at Y8 now.