Hingis filed court papers in New York last Friday alleging a pair of Sergio Tacchini shoes made her withdraw from up to a dozen tennis tournaments.
Hingis was paid almost $5 million to wear the shoes, but her contract with the company was terminated in 1999 when she wore adidas at the Australian Open.
The company chairman, Sergio Tacchini, accused her of damaging the brand's image.
But Hingis claims the shoes were defective and unsuitable for competition. She also says she acquired a debilitating foot injury at the US Open in September 1998.
Hingis had her feet examined by a Manhattan doctor who confirmed the chronic injury was caused by the tennis shoes manufactured by Sergio Tacchini, the court papers claim.
Hingis believes the shoes did not provide her with enough support to play competitive tennis.
The shoes were defectively designed and manufactured, the court papers claim.
Hingis withdrew from tournaments in Germany and Switzerland in 1998 before seeing an Italian foot expert.
She claims the orthopaedic specialist recommended the shoes be modified, but the company failed to do so.
Her feet were treated at nine separate tournaments in Manhattan, Philadelphia, California and South Carolina.
Hingis also says she withdrew from the Wimbledon doubles tournament in June 1999 because of her injured feet.
Hingis won the last of her five Grand Slam singles titles at the Australian Open in 1999.
She has lost four major finals since then.
Tennis star Martina Hingis is suing a sports shoe company for $35 million for giving her sore feet.






