This paper presents a path loss model for wireless body area network (WBAN) on-body communication. The modelling is based on pathloss measurements in an office room with various activities. The studies are done for several on-body radio channels and with two identical microstrip patch rectangular antennas for the frequency range of 2.89-3.10 GHz. A magnitude of each frequency sampling is applied to the post processed measurement data resulting parameters for a path loss model. It was shown that pathloss for on body communication is not only based on propagation distance, but also based on the propagation in each human body self, the activity that done by the human body and also the type of activities, hard or not. We then get that the most pathloss happen in body parts which do the hard activity. The next we get that the direct distance of the body parts is lower than the pathloss when there is a shadowing. By comparing with the log normal distribution pathloss for on body channel WBAN, we find that there is the different about 32.25 dB pathloss when human body do most activity in ankle, and 26.41dB pathloss when human body do most activity on foot.