The ab wheel is an effective piece of equipment for core strengthening. However, do not let the fact it’s lightweight, and appears easy to learn, fool you. A little movement goes a long way. Most of you will feel it work immediately starting slow and easy, and will have to work up slowly to more difficult moves.
Simply put, the ab wheel works your front stomach muscles, sides (the obliques) and back muscles; all the supporting trunk muscles known commonly today as your “core”.
In most cases, you will start slowly rolling forward (I suggest on carpet to avoid slipping when new to this) keeping your trunk stable as shown, rolling out a foot or so only, then slowly rolling back to the start position.
Over time you will gradually go further, perhaps change floor surfaces, and begin to make arcs to right the and left to challenge the core muscles. This is by no means a necessary piece of equipment; it’s handy for certain sports-specific training, but for most of us it would just be something challenging and different. I like to share all the equipment I use here in my studio.