Multiple Olympic and world champion Missy Franklin`s preparations for this week`s Pan Pacific Championships on Australia`s Gold Coast have been hit by back trouble, US team officials said Wednesday.
The 19-year-old American star suffered back spasms in training and was undergoing treatment ahead of her opening scheduled swims at the meet on Thursday.
The quadruple London Olympic gold medallist and nine-time world champion had to be assisted from the training pool late Tuesday and was a no-show at a team media conference on Wednesday.
A US official said medical staff would reassess Franklin`s condition on Thursday, when the four-day Pan Pacs meet begins.
"It`s a fluid situation," he said of Franklin, who was spending the day resting.
Franklin is scheduled to contest the 200 metres freestyle and 100m backstroke on the meet`s opening day. She also qualified for the 200m backstroke and 100m freestyle and looked set to contest the three relays.
Franklin, whose back was strapped with medical tape at the Tuesday training session, said she was feeling better on Wednesday.
"Had some back spasms after workout today, already feeling better! Thank you for all your support and concern?" Franklin tweeted.
Franklin is the current Laureus sportswoman of the year, having beaten tennis great Serena Williams and Russian pole vault queen Yelena Isinbayeva for the global honour.