So I have been loving combining abs exercises with upper bod ones, minimal rest in between. Pick a core exercise (which aren't strictly core) from exercises 1-4 and superset it with 5-7.

8-12 reps x 4 sets

1. Hollow body pullover crunches

2. Static crunch with reverse crunches 3. Leaning biceps curls

4. Static crunch with triceps extensions

5. Static squat lat pulldowns

6. Front raises

7. Shoulder presses