If you were to trace somebody's art, that'd be one thing. You should either ask for permission, or not do it in the first place, in that case.
But it's a straight-up given that in order to make a successful piece you need to have reference, or else have a very strong visual library in your head (which you can only build by using reference over and over until you've memorized how to do it).
Since you're referencing a drawing, unless that drawing is photorealistic and none of the anatomy is abstracted, it would be best for you to take a photograph of yourself or another person in the pose in question so that you can see how the body is really doing whatever the pose is and compare it to the drawing so you can see where the artist abstracted, exaggerated, or didn't know what s/he was doing, etc.
It's nice to say, "I was inspired by ____." You might as well. But, artists copy all the time because that is what we DO in order to build a visual library. Unless you're copying some iconic, unmistakably-not-yours pose, or jacking the entire composition, I wouldn't worry about going, you know, "This girl sitting here on this bus bench, I drew her after sparklepooky83's 'Girl No Sitsu In Bussu Chan' on deviant art n_n *linku* Go love her!. "