Perhaps you should try some spelling variations:
"synchronised swimming" » "synchronism swimming", "synchronize swimming", "synchronised stemming"
"synchronising swimming" » "synchronising stemming", "synchronism swimming", "synchronisations swimming"
"synchronized swimming" » "synchronized stemming"
"synchronizing swimming" » "synchronizing 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 ((("synchronized swimming") or ("synchronizing swimming"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("synchronised swimming") OR ("synchronising swimming"))) OR ((("synchronized swimming") OR ("synchronizing swimming")))).
• Removing quotes may allow a broader search: (((( synchronised swimming ) or ( synchronising swimming ))) or ((( synchronized swimming ) or ( synchronizing swimming )))).
• Adding a wildcard symbol may retrieve word variants: (((("synchronised swimming") or ("synchronising swimming"))) or ((("synchronized swimming") or ("synchronizing swimming"))))*.