Absolutely! this is seen as production of heat as well as movement. I would like to see the momentum of energy generated by running put back in to the grid, so everyone who is running in gyms on treadmills or at work could help generate power.
Moreover, you could use the same principle of your dynamo on your bike by wearing a specific device around your knee connected to a battery.
There is even a club in Rotterdam that generates energy by the dancing people on the elastic floor (up and down). This is more a kind of publicity work, but it shows the endless ideas of how to generate energy.