Lately my short-legged dog has taken to walking with her nose on the ground...sniffing. Our walks have become slower and I feel like I am dragging her. How can I correct this? I need the exercise and she does too.
Correct sniffing? That would be like trying to correct you for looking - it's what they do.
I like Pawz's idea of putting a cue word to the sniffing. I also like the idea of...letting her sniff. As was said, once they take in the information they are looking for, usually they are good to move on. Walking isn't just exercise for a dog, it's a means to get to the next place of importance to them.
Notice the areas your dog sniffs. Are they generally the same places? Probably some importance for her there. Plan a route around these places. You'll likely notice patterns emerging. I know with Wally, I KNOW where he's going to sniff the most, so my routes connect these places, most of them at the beginning and end of the walk. So he gets to sniff and keep up with the news and gets that satisfied, then we can start the physical exercise. Then at the end, he can "unwind" with more sniffing and marking if he wants before we end up back at home.
Also, if there's safe places where there's nothing much of importance to her and isn't curious about it, try the exercise walks there. She probably won't sniff much. And if she does, let her. Then when done, start up again. If you want, you can give her some sniff time, then cue her to return so you can keep walking. I do this with Wally. He gets to sniff, I get to call him to continue, we both get something out of it.
Think of it like this - she's getting both her mind and body worked, which is double for your trouble.