Visualization of sports performance data on Androidmobile-phone acquired through a Bluetooth link

Sammanfattning: Recent developments in mobile architecture and the need for objective performance measurement in kayak elite sport coaching induced the opportunity for this study. We developed an application for smartphones that will help athletes evaluate their perfor- mance. Several sensors measure forces, acceleration and distance. Data is sent through a wireless connection and stored in a smartphone. The aim of this study is to evalu- ate technical possibilities on the smartphone in a coaching environment by comparing previous system proposals, to evaluate the learning situation when using the device as technical aid based on learning theories and technical limitations, and to design visualizations on the mobile device according to technical possibilities and learning theories. Technical research is used as a framework to compare the proposed system design to others, in sense of components used and the devices’ technical possibilities. Feedback-theory is used to explain the learning of motor skills and theory about visual literacy in the understanding of visualizations. Last cognitive models from Cognitive Load Theory (CLT), Multimedia Learning (ML) and Human Computer Interaction (HCI) are presented. Visualizations on Android smartphones are limited by screen size and navigation possibilities. The challenge for the athlete and coach is to see patterns in acquired data and to translate it to manageable exercises suitable for the motor skill domain. In the motor skill domain it is important for the athlete to understand what behavior, e.g. what element of a movement to learn or improve. In current system designs the athlete has to wait a long time between performance and feedback. The athlete has to remember a long series of movements and match it with measured data, which could be ineffective according CLT. The design of feedback will depend on the learning situation, technical possibilities and the information to process. When the environment is cognitively demanding the visualization should be easy to understand and the information easy to apprehend. Complex data could be presented in a graph on the mobile device but a big screen is recommended for this. The technical possibilities with the Android platform are suffi- cient for the intended use. Direct feedback in real-time is preferred to post-visualization in motor skill exercises.