Bodywork: Adam Cohen looks at fitness trends for new year

Adam answers

10. Activity trackers. Pedometers — remember those? — have been replaced by activity-tracking bracelets like Nike's FuelBand and the Jawbone Up. Equipped with accelerometers, these devices will keep you constantly aware of how active you are (or aren't). With accompanying apps, you can compare your data with friends and start a friendly competition. Or just feel guilty.

9. Hot yoga. Yeah, it seems likes there's always a new yoga craze these days. This year, gyms and studios will turn up the heat for clientele who love to sweat and stretch in triple-digit temps.

8. Tough mudders. Bored with the garden-variety 5k and triathlon? Well, just join the hundreds of thousands of weekend warriors competing in extreme obstacle course races that offer the chance to crawl through pits of mud, plunge into pools of icy liquid, and get shocked by live electrical wires.

7. Body-weight workouts. Way back when, we used to call these things push-ups, pullups and sit-ups. But in the American College of Sports Medicine's annual survey of what's hot, these back-to-basics exercises that use minimal equipment (and, hence, are refreshingly cheap) ranked near the top of the charts.

6. Certified fitness professionals. Despite all the great exercise technology and information at our fingertips, it seems that more than ever we want a real, live human being to guide us through workouts — and to yell at us when we start to slack off.

5. Demographic-specific classes. As research increasingly demonstrates that health and fitness are cradle-to-grave propositions, expect to see more fitness offerings targeted specifically at children and the elderly. Pilates for preteens, anyone?