How to tell Nordic walking is working your upper body

Check out this video of Nordic walking instructor Malin Svensson on a local newscast a while back. At 1:38 to 2:26, she takes the walker through a series of checks to demonstrate that using poles engages the upper body. Then she explains why it works that way.

At 4:04 she explains why hiking/trekking poles won't work properly for Nordic walking.

Try it on yourself. You can use a broomstick to try it out.