If your arm isn't moving because you're holding a handle then the Surge sees no steps to count. If the GPS is on in one of the walk/run modes then I believe the lack of steps is a trigger to suspend tracking since the device believes you're not walking under your own steam.
For the tracker to count, your arm needs to be free to move as your body takes steps (or you need to put the tracker in a pocket or similar).
Mike | London, UK
Blaze, Surge, Charge 2, Charge, Flex 2 - iPad Air 2, Nokia Lumia 925 (Deceased), iPhone 6
Take a look at the Fitbit help site for further assistance and information.