I was suspicious of the enthusiasm. People who do cross-functional fitness, also known as high-intensity workouts or, more popularly as “CrossFit,” talk about it in rapturous tones. They blather on about how sore they are, using terminology foreign to us normal folk. They talk about how you can get in the best shape of your life with a 10-minute workout.

      Skeptical didn’t even begin to cover how I felt. I had no interest in this trend. Nope. Not me. Not in this lifetime.

      Then my friend Emily turned. She wasn’t just in; she was all in. The betrayal!

      Emily wanted me to try this high-intensity functional fitness, too. Over dinner, she kept saying how much she loved the workouts and how great the community was. Her gym was close to our respective homes.

      I looked into her gym, which utilized the CrossFit brand and required newcomers to take an introductory series that teaches you the exercises and how to safely navigate the rigorous workouts. The price made me gulp—$150 for a month—and this was several years ago. This particular intro series required 12 classes over four weeks—that’s three classes a week. That seemed like a lot of money—and time—to commit up front.

      OR TRY . . . KETTLEBELLS

      Advocates of kettlebells say you can get stronger than you ever thought possible—including core, leg, shoulder, and grip strength plus general conditioning—by working out with the round-shaped weights with handles that come in various sizes.

      I wanted that.

      I took a class at a studio that teaches Russian-style kettlebell technique, learning to swing and use the kettlebells for general strength. You train barefoot, which at first seemed dangerous to me, considering that even light kettlebells can hurt if dropped on a bare foot. But feeling your feet makes a difference for technique, according to the trainers, though not all studios train this way.

      After a warm-up, we worked a halo, holding a kettlebell in both hands with the handle down and circling the kettlebell around our heads, as close to hair and ears as possible. Halos warm up the shoulder girdle, strengthen the back, and mobilize the shoulders.

      We practiced squats, lowering hips toward the floor. Then we learned a hip hinge, folding at the hips, sticking your butt out, and engaging your core. For swings, holding the bell by the handle, we hinged first, dragged the kettlebell back, felt our weight in our heels, then thrust hips forward so the bell floated forward to shoulder height, repeating the swing 10 times, using a breath technique to sniff in and then hiss breath out during the swing.

      I struggled with my hip hinge. If you hinge more at the hips, you won’t leak power from your core, one trainer said. I lost power at the top of the swing, pushing my hips forward instead of standing up. I muscled my kettlebell up with my shoulders. Clearly, I needed to take this class again.

      We also worked deadlifts with heavy kettlebells. I hinged at my hips, squeezed my legs and upper back, sniffed, exhaled, and stood up with my kettlebell.

      The goal is to master technique so that you maintain good form even if you swing a kettlebell hundreds of times in one class. I can’t wait for the day I master a beautiful kettlebell swing.

      Many gyms and trainers offer a variety of multifunctional high-intensity interval training (HIIT) classes. It’s often marketed as “CrossFit,” a worldwide brand with numerous affiliates, but you can easily find gyms that use similar approaches and get the same results.

      This style of training includes bodyweight exercises such as pull-ups and push-ups; weightlifting using barbells (you’ll squat and learn Olympic lifting, snatching a barbell from the floor and raising it over your head); cardio,