if you work out three times a week training your chest and back one day, your legs on another and your arms and shoulders another, just bolt on the upper abs moves on chest day, the lower abs moves on legs day, and the obliques and core moves on arms and shoulders day. Alternatively, you can do them as standalone sessions for a quick and effective abs workout.
Upper abs workout
Dumbbell crunch Reps 10 Rest 10sec
Crunches Reps 20 Rest 90sec
Tuck and crunch Reps 15 Rest 10sec
Modified V-sit Reps 12 Rest 10sec
Crunches Legs Straight Up Reps 12 Rest 10sec
Lower abs workout
Hanging leg raise Reps 10 Rest 10sec
Hanging knee raise twist Reps 12 each side Rest 10sec
Hanging knee raise Reps 15 Rest 10sec
Toe Touches Reps 15 Rest 10sec
Garhammer raise Reps 20 Rest 90sec