GHD sit-ups heavily recruit the abs, and I love how much I feel this exercise across my torso — it helps engage my core most of all the ab workouts I do. However, I don’t own a set of rippling ...

For intermediate-level exercisers, try a 400-meter carry and 20 GHD sit-ups to parallel with 15 lb or 20 lb dumbbells. These are guidelines only, so find a happy medium if necessary.

I swapped out the GHD sit-ups for ab mat sit-ups (as my lower back is a bit temperamental), and started from 40 calories on the SkiErg instead of 50 as, quite frankly, I thought I’d be there all ...

GHD sit-ups are the type of advanced abs exercise reserved for those in the gym who like to send their core muscles into meltdown. Think of them as the sister of the sit-up that likes to show off.