Resistance bands are the perfect tool for sculpting or toning your muscles on-the-go — whether you’re traveling across the country or just down the road to your local park, says Cris Dobrosielski, a spokesperson for the American Council of Exercise and the owner of Monumental Fitness Results, in San Diego, California. “Doing more reps, say 3 sets of 15 reps, provides a muscular endurance benefit, we well as some amount of hypertrophy, or muscle building,” he says.