This 20-minute workout from Women's Health+ Ultimate Abs Challenge focuses on dumbbell rotational abs moves. Here's how to get stronger and build core muscles.

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Reverse lunges are beneficial because "they put less stress on your joints [than forward lunges do], and give you a bit more stability in your front leg as you drive through it," Earnest explains ...

For the Women's Health Flex Challenge, certified trainer Ajahzi Gardner leads you through a 12-minute total-body strength training circuit that uses only dumbbells.

Women of all ages should focus on strength training to help reduce risk of dementia, said exercise physiologist and nutrition scientist Dr. Stacy Sims (not shown).