When combining rings and dumbbells, you need to start slow. A proper progression starts with isometric holds before moving on to dynamic movements. But this is still challenging. If you do a body weight Pull-Up on a stable object like a bar, the only moving object is your body. All you have to worry about is pulling your body to reach the bar. But when performing ring training, you cannot rely on the stability of a bar; you have to stabilize the rings while performing the various dumbbell movements. This requires more work on your part, more control, tension, concentration and effort.