http://www.bikeforums.net/search.php?searchid=3210704

For future reference, the search string was: "out-of-phase" "in-phase"
Search in Forums field: Tandem Cycling

Note: I noticed that the URL for the seach results didn't work. They may have changed the way the search engine archives data so you may just need to build your own search string using the aforementioned criteria.