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

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

Sit-ups: Techniques, benefits and variations on the classic

Forget sit-ups — 10 best crunches and variations to…

How to Do a Correct Sit-Up, Plus Benefits and Variations

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

The Major Differences Between Sit-Ups and Crunches

Why Sit-ups Are Bad For Your Back and the Right Exercise To Try

How to measure your core strength: 3 core tests

5 Easy Ways to Test Core Strength - wikiHow

Core Training –

Ditch the Situps: Better Core Training for Hunters

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

20 Best Core Workouts For Women - Core Exercises For Stronger Abs

The Truth about Whether You Should Crunch or Plank Your Way to a

The Best Sit-Up Variations for a Strong Core

Planking is in, situps out for Navy physical readiness test