A3: V-Up (or variant)
3 x 20 reps
Don’t let ANY arch at all in your back. Touch hands behind and then touch ankles or feet. Bent legs make this easier - straight legs more difficult! You can start with harder version and then make the reps easier as you get tired. This should all be ab work - if you feel your back working or it doesn’t feel good move to an easier progression or stop altogether.