Russian Kettlebell classes are popping up at places like the SweatShop in Saint Paul, Minnesota, and the Ridgewood, New Jersey, YMCA. The kettlebell is a weighted iron ball with a handle that comes in weight increments from 9 to 88 pounds. The workout is for approximately eight people and is touted as being useful for core strength conditioning as well as cardiovascular fitness.

Punk Rock Aerobics targets the under-30 crowd with punk rock music and attitude. The 90-minute classes cost $7 at Boston’s Middle East Club. Participants use bricks as hand weights and do “guitar windmills” instead of traditional aerobics moves.

Bring It On! is a Crunch class that combines the dance routines, jumps, plyometrics and flexibility training that cheerleaders do while training.

Therobics is a class for older adults that uses a system of interconnecting elastic bands and tubing developed by Thera-Band®. The movements mimic activities of daily living like reaching, stretching, twisting and lifting.

Triad is an Equinox Fitness creation that features 30 minutes of indoor cycling, followed by 30 minutes of strength work and 30 minutes of flow yoga.