Barbell Ab Rollout - On Knees

How to do it

Hold an Olympic barbell loaded with 5-10lbs on each side and kneel on the floor.
Now place the barbell on the floor in front of you so that you are on all your hands and knees (as in a kneeling push up position). This will be your starting position.
Slowly roll the barbell straight forward, stretching your body into a straight position. Tip: Go down as far as you can without touching the floor with your body. Breathe in during this portion of the movement.
After a second pause at the stretched position, start pulling yourself back to the starting position as you breathe out. Tip: Go slowly and keep your abs tight at all times.

What muscles does the Barbell Ab Rollout - On Knees work?: Mainly the abs, with help from the lower back, shoulders.
What equipment do I need?: Barbell.
Is it good for beginners?: It is rated expert level, so learn simpler versions first.
How do I track progress on it?: Log each set and beat the weight or reps from last time. Liftrung shows your last set beside the next one and estimates your one-rep max from your sets.

Exercise descriptions: free-exercise-db, public domain.