Perhaps you should try some spelling variations:
"synchronised swimming" » "synchronism swimming", "synchronize swimming", "synchronised stemming"
"synchronising swimming" » "synchronising stemming", "synchronism swimming", "synchronisations swimming"
"synchronizing swimming" » "synchronizing stemming"
"synchronized swimming" » "synchronized stemming"

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (((("synchronised swimming") or ((("synchronising swimming") OR ("synchronizing swimming"))))) or ("synchronized swimming"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("synchronised swimming") OR ((("synchronising swimming") OR ("synchronizing swimming"))))) OR ("synchronized swimming")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"synchronised swimming\") or (((\"synchronising swimming\") OR (\"synchronizing swimming\"))))) or (\"synchronized swimming\"))".
• Removing quotes may allow a broader search: (((( synchronised swimming ) or ((( synchronising swimming ) OR ( synchronizing swimming ))))) or ( synchronized swimming )).
• Adding a wildcard symbol may retrieve word variants: (((("synchronised swimming") or ((("synchronising swimming") OR ("synchronizing swimming"))))) or ("synchronized swimming"))*.