I don't think I'm alone in saying sit-ups aren't fun. I don't know if it's because I need to have someone or something there to make sure my feet stay put on the ground during the full movement or ...

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I don't believe that sit-ups or crunches are must-haves in any core routine. In fact, I steer away from them in favor of other functional core exercises that build a strong midsection, and this "core ...