A modular multifunctional exercise assembly for walking, running and biking exercises includes a treadmill. A stationary bike is reversibly positionable on and couplable to the treadmill. A screen is coupled to the treadmill and is reversibly couplable to the stationary bike. The screen is configured to interact with a user who is selectively positioned on the treadmill and the stationary bike. The improvements are the stationary bike that is reversibly couplable to the treadmill and the screen that is coupled to the treadmill and which is reversibly couplable to the stationary bike.