This exercise is torture on your abs, obliques and shoulders — and no, it's not planks or sit-ups (so I tried it)

The starburst side plank variation strengthens the shoulders, abs and obliques. Here's why we love it at Tom's Guide.
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Forget sit-ups — this dead bug variation challenges your core stability

We’ve said it before, and we’ll say it again: when building a strong core, sit-ups aren’t always the best option. Not only can regular sit-ups and crunches put strain on your lower back, you’re only ...

If You Can Do This Many Sit-Ups After 55, Your Core Beats Most People Your Age

Find out how many sit-ups after 55 signal a strong, healthy core and use this 60-second test to track your strength over time.