Decline angle, weight overhead, full sit-up burn.
Keep arms locked overhead so the abs do the work, not an arm swing.
Holding a dumbbell locked out overhead turns the decline sit-up into a long-lever core lift, because every centimetre the weight sits beyond your chest multiplies the demand on your abs. The locked-out arms also remove any chance of swinging your way up, so the trunk alone drives every rep. It is one of the harder sit-up variations going, earned only after strict decline sit-ups are routine.
Leverage. The further the load sits from your hips, the harder your abs work with the same dumbbell, and locked-out arms kill the arm-swing cheat that plagues normal weighted sit-ups.
Light, seriously. A small dumbbell held overhead on a decline feels heavier than double the weight on your chest. Start lighter than your pride suggests and add slowly.
Yes, that drift is the weight helping you up. Keep the dumbbell stacked over your shoulders for the whole rep, and if you cannot, it is too heavy for now.
