Combine cardio with core work to reap the flat-belly benefits of both types of sweat sessions in this quick, 20-minute workout. To make this a 30-minute workout, run, bike, or row for 10 minutes or do this 10-minute no-equipment cardio workout.
Equipment needed: jump rope and medium-weight dumbbells (five to 10 pounds)
Image Source: POPSUGAR Photography / Sheila Gim