A steeper crunch with extra load for deep ab burn.
Lead with your ribs, not your hips, and keep tension on your abs.
Adding load to the decline crunch turns your abs into a muscle you train like any other, with progressive overload instead of endless reps. Holding the weight on your chest keeps the resistance close to your axis of rotation, so the crunch stays strict while your core handles more per rep. This is how visible ab thickness is actually built, provided every rep stays a curl and never becomes a swing.
Hugged to your chest, as the setup describes. Held at full arm reach it turns into a leverage circus, and held behind your head it strains your neck. On the chest keeps the load honest.
Enough that 8 to 15 strict reps is genuinely hard. If you have to yank your torso up or your hips start doing the lifting, the load is too big for today.
Building the abs gives them visible depth, it does not blow your waist out. Waist size is dominated by body fat levels, not a couple of sets of weighted crunches.
