Paul Widerman, who created SmartBells, went outside the fitness box, challenging the traditional linear movement of weight-lifting.
"The whole idea is that you move in circular patterns and blend with gravity," said Widerman. "You move to use muscles synergistically and flow."
So there's no stop-and-start to the workout. In fact, when trainers and students experienced SmartBells for the first time, they described them as "smooth and fluid."
"Dynamically, functionally, this really makes the workout more on how your body moves," said trainer Marc Natividad.
"The repertoire of exercises is virtually endless," said trainer Evlynne Householder.
Perfect for experts needing to continually challenge their students.
"Gone are the days where you only had step on your schedule," said Householder. "The members eat everything up. They love the variety."
The SmartBell weighs slightly less than five pounds. There's also a pound-and-a-half LightBell for kids and seniors, and 12-pounders for the uber-fit.
Used in yoga, Pilates and conditioning workouts, the ergonomic design makes it easy to use when lunging or crunching; often impossible with weight plates or dumbells.
What also makes this dumbbell a SmartBell: You can take it to work. So much so, they sell a desktop model for those suffering from neck, wrist, and shoulder problems.
"When you're working on your computer and you're stiff, you slow down, become less productive," said Lance Stewart, ThinkFit. "Just pick up your Smartbell and move for a few minutes. It actually helps you improve your range of motion as well as balance and coordination."
SmartBells are also utilized in physical therapy.
"They weren't originally designed for rehabilitation, but they really are fantastic for therapy and rehabilitation," said Widerman.
Even athletes and military are catching on.
"US Navy SEALs, the Marines, quite a few professional sports teams [use SmartBells]," said Stewart.
Take a class at a gym like Spectrum or buy one of your own. Eighty dollars will get you a SmartBell and instructional DVD.
Not cheap, but for those looking to alleviate pain, gain more energy and get in shape: "You can do so many varied things with them. I want one," said Taub.