An exercise apparatus for performing an armless push-up allows a user to engage in gravity-driven, resistance exercise with improved pectoral isolation and range of motion as compared to known push-up devices. The exercise motion is performed using a yoga-inspired, bent-elbow plank position by a prone (face-down) user. The user places each forearm on a trolley mounted at the top of opposed rails that are inclined toward an elevated centerline. As the trolleys move down the opposed inclined rails, the user's chest descends down; and as the user pinches his elbows together using the pectoralis muscles, the trolleys move up the inclined rails again. Gravity imparts a centered user balance, and the resistance can be varied, such as by changing the incline of the rail assemblies, changing the weight associated with the user, or by adding resistance to the trolley movement.