Accelerometers are a building block of many fitness tools. Engineers integrate these tiny chips into products that track your baseball or golf swing, your smartphone's position, your car's navigation system or, if you're more military-minded, your missile guidance system.
Athos uses a six-axis accelerometer as a cornerstone of its capabilities. But muscle activity tracking is what makes Athos stand out from a field of accelerometer-based competitors.
To that end, Athos' EMG sensors detect electrical signals produced by your moving muscles. Paired with the Athos software, the system can track muscle effort, muscle toning and muscle fatigue, all of which are important to understanding how your body is responding to a particular activity.
The sensors also help the core unit determine what's called your maximum voluntary contraction, or MVC. In essence, when you first use the system, you calibrate it by doing some basic exercises. Using that data, the core determines your MVC, which is the upper end of safe exertion for someone working out alone at home.
As of April 2015, the Athos collection comprises a shirt and a pair of shorts. Both are made from a stretchy and snug compression-type material that conforms to just about any body type. The clothing is designed for both male and female body types, and the fabric wicks away sweat while it simultaneously collects data.
The sensors aren't just plopped into random places. They have specific job duties. For example, the shorts sensors track electrical activity in certain muscles, including the hamstrings, the inner and outer portions of your quadriceps and both sides of your gluteus. The shorts also feature four heart-rate sensors. The shirt has even more sensors, including 14 EMG detectors, four heart rate monitors and two breathing sensors.
When the smartphone app receives all of this data, it displays a graphical representation of the body area you're targeting. The image indicates your total effort as a percentage and then splits that effort in two, showing you whether your right side is overcompensating for your left, or vice versa. An illustration of your muscle groups is color-coded to represent your exertion level. Green shows that you might be taking it too easy. White indicates that you're probably pushing too hard.
It's designed be quick and easy to read so that you can absorb the information by peeking at your smartphone's screen in the middle of a workout. Then you can adjust your effort on the fly or stop and reconsider your approach.
As of spring 2015, Athos is compatible only with Apple's iOS. The company is planning to launch an Android version as well.