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

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