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.

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

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Are sit-ups worth the pain and are you doing them right? We asked