This exercise only targets the abdominal muscles, so it’s not a functional core workout. Crunches can be hard on your back and neck, and may not be safe for everyone. Share on Pinterest The crunch is ...

The leg extension, or knee extension, is a type of strength training exercise. It’s an excellent move for strengthening your quadriceps, which are in the front of your upper legs. Leg extensions are ...

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Planks are a simple, equipment-free exercise that strengthen your core, improve posture, and protect your back ...