Superset 250 Wheel & Oblique planks!I build up the reps with the toughest move that's very hard to do unless you have a solid core strength foundation.I recommend you film yourself to check your form, you want to avoid ending in a hip extension position with the butt up in the bottom!If you end up with back pains you'll likely losing your stiffness needed.When you flex or tuck your pelvis, then keep that tension throughout the set.