How do we "cancel out" the torque from running? Running certainly causes a torque on our body, as we are propelled forward via our feet; why doesn't this torque cause our bodies to spin about their center of mass?
 A: EDIT: The "old" explanation below is quite informal, as gravity cannot produce a torque around the center of mass. See the new explanation below it.
Humans lean forwards slightly as they run (more so if they run faster, and have to counter larger drag forces). This makes gravity exert a counter-torque that exactly balances the torque produced by action of the feet. Here we consider the potential axis of rotation being at the point of contact with ground. It's a bit more complicated than outlined above because running is quite a complex motion, but using gravity as counter-torque is the basic idea of it.
Torque is especially high as runners are accelerating. In videos, you can see them leaning forward a lot as they start running at high acceleration and gradually straightening as they reach their steady speed.
EDIT: Actually, while gravity and leaning are key aspects of how running works, the explanation above was not correct. Properly considering possible rotation as around the center of mass, it becomes clear that gravity cannot contribute a torque. Instead, the force from the foot in steady speed running can be split into two components: an upward "normal" force that counters gravity, and a forward "propulsion" force that counters air friction. Humans maintain an angle of leaning such that these forces cancel. Leaning more reduces the torque from the forward force and increases the torque from the upward force. Of course, gravity matters because the normal force must be equal to it on average (to avoid sinking into the ground or floating upwards).
