Sports and fitness features not only dominate the wearables market, but continue to drive adoption, according to a report from ABI Research.

Activity tracking, which includes simple step counting as well as more advanced tracking of specific types of movement, was the most popular feature of wearable devices in 2013 -- 16 million wearable devices with this functionality were shipped. After activity tracking, heart rate monitoring was the most popular feature of wearable devices in 2013. ABI said heart rate monitoring wearables saw 12 million units shipped last year. ABI characterized heart rate monitoring wearables as "single function devices that communicate with nearby hubs such as smartphones or activity sports watches".

ABI Research principal analyst Jonathan Collins said heart rate and activity monitors will outpace shipments of smart watches and smart glasses at least through 2019. The company also added that these wearables will move into healthcare services as well.

The researchers specifically point to Garmin, Polar, Nike, Fitbit as companies that will continue to ensure that sports and activity tracking remains a key wearable functionality. These activity tracking wearables will also be improved upon in the coming years as smart watches and smart glasses become more prevalent.

In another recent market research report on wearable devices and activity trackers, Canalys predicted that the smartwatch category and the activity tracking wearable will converge. Canalys expects 8 million wristworn wearable with a focus on medical or wellness features to ship in 2014.