4 Fresh Twists on Old Workout Routines

The workout: A high-energy, 45-minute routine done completely on an elevated, angled trampoline (known in gymspeak as a rebounder) at Crunch gyms nationwide. You'll rotate through a series of jumping jacks, squats, and arm exercises—all while keeping your core fully engaged to stay balanced.

Why you'll like it: With its modern mix of aerobics and step moves (and a nod to cheerleading's pep) plus a yoga-inspired cooldown, Elevation packs in cardio, toning, and mindfulness. Need proof? A recent pilot study at New York's Hospital for Special Surgery found that exercisers who did rebounding workouts 20 minutes a day, three times a week for two months experienced a 68 percent increase in proprioception—awareness of your body in space—which can improve balance. Not to mention the thrill of feeling like a kid jumping on the bed. (If you're not near a Crunch, you can order a rebounder and workout videos at urbanrebounding.com.)

The workout: This surfing-inspired gym class uses a body-weight-activated surfboard contraption made to mimic the real thing; you can adjust the board's level of instability to the degree of difficulty you want. Targeting the same muscle groups surfers use, the workout can include a taxing series of lunges, squats, and push-ups. (Surfset classes are offered in nearly 50 locations across the country, or you can order your own board, plus access online workout videos, at surfsetfitness.com.)

Why you'll like it: Sure, it's a bit gimmicky—but it's also genuinely exciting and has serious payoff. You'll craft a long, lean body, burning 400 to 900 calories in just one session. And thanks to the routine's Zumba-like fun, your workout will seem less like, well, work.

The workout: With a dozen obstacles to test your mettle, this worldwide series of 5K races is like circuit training on steroids—expect to scale 12-foot walls, crawl under barbed wire, and jump over fire. You don't have to train for the Warrior Dash (runners and walkers of all fitness levels are welcome), but select Anytime Fitness gyms nationwide now offer Warrior29 classes to prepare you. For race dates in your city, visit warriordash.com/locations.php.

Why you'll like it: Consider this a far more exhilarating way to improve your endurance, upper-body strength, and agility. And the end-of-course party with live music and beer is the perfect way to celebrate crossing the finish line. Added incentive: Warrior Dash supports the St. Jude Children's Research Hospital; participants have raised more than $5 million to date.

The workout: Set off into the clear blue on a specially designed board, using only a paddle to propel yourself. Each stroke tones your triceps, glutes, back, and abs. "This workout absolutely nails your core," says Gina Bradley, the founder of Paddle Diva, a SUP training program for women in Long Island, New York. "Every movement feels like you're doing a crunch on one side." SUP has become an increasingly popular beach vacation activity, and some companies now offer SUP excursions to oceans and lakes in cities across the country.

Why you'll like it: Cultivating balance, core strength, and a love of the water, stand-up paddling pays homage to Pilates's strength building with the head-to-toe muscle engagement of swimming. Unlike rowing, which relies on symmetrical movement, SUP is asymmetrical—you're challenging one side of your body at a time—which, as Bradley explains, engages muscles that aren't normally used during the average gym workout.

Next: 7 fun exercises your trainer doesn't want you to know about