**1. Introduction**

Distance running is a very popular sport. Two main reasons for this popularity are simplicity and the health benefit, as running can be done in small and restricted time-frames and does not require a specific location. Besides sports gear, no equipment is needed. Moreover, running improves health. Studies have shown that aerobic endurance training like running can reduce blood pressure [1] and that moderate running twice a week (>51 min or six miles) reduces overall mortality risk and the occurrence of cardiovascular diseases [2]. However, overtraining can also lead to a higher risk of injury of the lower extremities for distance runners [3].

Tracking running performance over time can prevent overtraining and greatly support a healthy and effective training. A training diary helps to maintain the right training intensity and volume, which are essential for both performance and health enhancement. Training records are also motivating, as they highlight both effort and progress. However, a precise, objective, and easy measurement of relevant parameters is needed. Two common parameters that both professional and amateur runners use to track their performance is the average velocity and total distance. With these parameters, the running workout can be easily categorized, rated, and compared. In the past, runners estimated the distance of a predefined running track and took time with a stopwatch to calculate the average

velocity of a distance run. With the rise of wearable technology in recent years, easier and more precise methods have become available.
