I think this is one of those cases where the story should take precedence over the rules.
If the rules are keeping a player from acting in a significant way - to carry the exceedingly heavy Maguffin from the Pedestal of Doom, even at a slow waddle, that's the rules destroying the drama of the scene. And in any case like that, the rules will always be in the wrong.
Discussion on game mastering Earthdawn. May contain spoilers; caution is recommended!