Sentence:  You are not doing a lot of heavy thinking when you are <WSD>schlepping</WSD>; you are performing useful but perhaps menial labor, usually in the service of someone else. <WSD>Schlepping</WSD> is not very glorious, but nonetheless one should not underestimate its importance. First of all, just because you are <WSD>schlepping</WSD> does not mean you are forbidden to think. In fact, just the opposite is true: Because the work content of <WSD>schlepping</WSD> includes little thinking, you can use this time to think and learn while you <WSD>schlep</WSD>. Many creative ideas occur during <WSD>schlepping</WSD>. For instance, how can I <WSD>schlep</WSD> this stuff with less effort? 
Meaning of the word marked with <WSD> tags:  To go, as on an errand; to carry out a task.