Understanding the behaviour of the human body when transiting from one locomotory pattern into the other has a great significance for the technological progress in the field of biomedical mechatronics. On the one hand, assistive systems such as exoskeletons can learn and perform multiple locomotory patterns, helping the wearer to increase his mobility. On the other hand, applications in the field of personal training, for example so-called activityor fitnesstracker, can be improved in regard to their classification accuracy of different locomotive patterns. The focus of this work is to investigate the transition region between walking and running in terrestrial surroundings. Therefore, a device is developed which allows to measure the speed as well as the occurrence of unsupported phases, which are phases where non of the feet touches the ground. Those two parameters allow to determine at which speed the subject is changing his gait pattern. The velocity measurement is carried out with a commercial low-cost interial measurement unit with six degrees of freedom and subsequent postprocessing with a filterless algorithm. A relative error of -2.85 3.15 % is obtained. Based on the data of 20 subjects, interesting insights about the transition region could be found. The results are compared to those of laboratory studies on a treadmill.