Sit-Ups, Crunches, Planks, Knee-Ups: The Evolution of Core Fitness

Core strength testing has come a long way from the straight-legged, twisting sit-ups used before World War II.

34 Core Exercises Top Trainers Swear By to Work Every Part of Their Abs

Sit-Ups, Crunches, Planks, Knee-Ups: The Evolution of Core Fitness Testing

Forget planks — this 15-minute crunches workout sculpts your abs

How to Do a Sit Up Correctly, Abs and Core Exercises

Fitness

Here's What A Good Core Workout Really Looks Like, thePTDC

Ditch the Situps: Better Core Training for Hunters

Forget sit-ups — these 6 exercises will help you sculpt your abs

Sit-Ups, Crunches, Planks, Knee-Ups: The Evolution of Core Fitness Testing

Can you do sit-ups while pregnant?

7 Exercises To Build Up Your Core if You Hate Sit-Ups