If you are just starting to exercise, don't practice at the same time. Abdominal muscles are close to the stomach and can easily absorb nearby nutrients. If you exercise at the same time, it will lead to poor dense structure and large outline of your other muscle groups. It is recommended to start from the abdominal muscles and practice for one cycle alone. After adaptation, I mainly exercise my chest muscles, because bench press and other projects can exercise my arms at the same time. Last night, my chest muscle training was followed by several groups of arm muscle weight training, which made me look like a bar:)