Join 49ers PREP presented by U.S. Bank and Sourdough Sam for a fun 30-minute virtual workout you can do from home featuring a "This or That" interactive game.

The key to an effective, pain-free crunch lies in the technique. It's not about mindlessly going up and down, but about engaging the right muscles and protecting your body. Here's a step-by-step guide ...

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 ...