Lumberjacks are big dudes. Because they are more massive than the average human, they also weigh more. This bigger weight (or, more properly, increased gravitational force) means that the must do more work to travel the same distance.
Since work is directly related to force in the direction of travel, much greater forces are required. As force the second derivative of kinetic energy and the first derivative of momentum, when one increases the rate of the others will as well.
As seen in the diagrams below, lumberjacks mean business. So does Ryan Gosling.