Above is a photo of Jimmy Stewart and Lew Ayres on skates. I don't know what movie it's from, but I'm guessing it was MGM's THE ICE FOLLIES OF 1939. I know that Stewart was a contract player and, as such, had to do roles that the studio told him to do. I did not know that that included skating with Dr. Kildare.
The image is from Dr. Macro's Scans, which has high quality old movie scans. And some more fun stuff, if you like old movies. And there are some films there to watch, film noir posters, etc. A real fun time-waster site, lovingly put together.