10-minute workout: Core strength

Arms-Out Roll-Ups Lie on back with knees bent. Hold a rolled towel, arms shoulder-width apart and raised above chest. Roll body up one vertebra at a time. Hold back at a 45-degree angle for two counts. Return to start. Do three sets of 10. PERFECT YOUR FORM: Keep your chin up and shoulders back to avoid rounding spine. DIAL IT DOWN: Perform a crunch instead of a sit-up. AMP IT UP: Stay in hinged sit-up position for five counts.

Elevated Toe Taps Lie on back with legs bent at just beyond a 90-degree angle, towel held across waist. Keeping knees slightly bent, touch toes to ground, one foot at a time. Do three sets of 10 taps with each leg. PERFECT YOUR FORM: Keep your pelvis neutral, initiating the movement from your abdominal muscles. DIAL IT DOWN: Do taps with knees bent to 90 degrees. AMP IT UP: Perform 12 to 15 crunches between sets.

Crunch Up & Over Lie on back with legs in the air, holding towel over head. Fold into a crunch, drawing knees toward chest and bringing towel over feet to ground. Hold for two counts. Return to starting position. Do 10 reps. PERFECT YOUR FORM: Pull belly button toward your spine throughout entire move. DIAL IT DOWN: Keep knees bent with feet on fl oor and perform the crunch series. AMP IT UP: Do 10 toe taps between reps.

Side Lunge Stretch Hold towel with arms in a V above head. Kneel on one knee and lunge other leg to the side. Keeping arms straight, lean to one side and hold stretch four counts. Then lean to the other side and hold stretch four counts. Do 10 reps, then switch legs and do 10 more reps. PERFECT YOUR FORM: Keep hip bones facing forward. DIAL IT DOWN: Perform movement while seated. AMP IT UP: Do the exercise while standing.

Calorie-Burning Bonus For an added core challenge, jump into plank between exercises and hold pose for 30 to 60 seconds.