Ready to torch your obliques? I added this simple standing ab exercise to my routine for a week. Here’s how I got on.

To work the lateral muscles while doing sit-ups, twist slightly to the left for five sit-ups, and then do the same thing to the right for five repetitions.

Optimal sets and reps: 3 to 4 sets of 15 to 30 reps As you come up in the traditional sit-up, twist your torso toward one side, bringing the opposite elbow toward the knee on the twisting side.

“Because you are twisting your torso during the movement, you are really engaging your obliques in a way that sit-ups and planks cannot do,” says Steve. Don’t be surprised if you need to opt ...