Plenty of fitness trackers can track your steps and measure your heart rate, but few manage to become exercise devices in their own right. WellShell, a device announced today from Tao Wellness, is an isometric exercise device that tracks your progress with companion apps for Android and iOS. The basic idea is thousands of years old: you squeeze something as hard as you can, and the effort builds strength over time. Tao's app offers 50 different isometric exercises, which involve applying pressure to the WellShell in different ways.

Tao says the WellShell will help people find time to exercise even when they are away from their home or a gym. The app coaches you using audio cues, telling you when to press, how hard, and for how long. You can use the app to track other activities, too, and input the meals you've eaten.

On one hand, it's hard to imagine many people squeezing their way to fitness. But it could offer a novel approach to building strength during your down time. Tao plans to run a crowdfunding campaign to build the first devices, with the WellShell shipping to its first customers in either the third or fourth quarter of this year. No pricing information has been announced.