An exercise machine with a movable belt includes a guard assembly with a flexible guard that extends towards the rear axis and is spaced apart from the movable belt by a first gap and is exposed by the housing body, a rigid guard positioned downstream of the flexible guard with respect to a moving direction of the belt and spaced apart from the movable belt by a second gap, and a channel disposed between the flexible guard and the rigid guard. The guard assembly protects the user from injury and prevents damage to the exercise machine.