The aim of this bachelor thesis was the overview of mobile phone evolution, current state and its usage in sport. We focused on stretching, presenting a group of exercises with photos and descriptions. We wrote about the effects regular stretching workout has on a person and pointed out a few guidelines on how to do stretching exercises properly. We also took a look into Android and other programs we used to develop our application. We then developed a mobile application named Tendo that facilitates this type of workout. Application guides the user through the workout using sound notifications. We included and explained the most important parts of source code.