Conversation so far:
When was Martina Hingis's first retirement from tennis?
In February 2003, at the age of 22, Hingis announced her retirement from tennis.
How long did Martina Hingis stay in her first retirement?
Martina Hingis was retired for approximately 2-3 years.
Why did Martina Hingis decide to retire in 2001?
Martina Hingis decided to retire due to her injuries and being in pain.
What injuries did Martina Hingis have when she retired in 2001?
Ligament injuries in both ankles forced her to withdraw temporarily from professional tennis in early 2003.
Did Martina Hingis suffer any other injuries besides her ankles?
Martina Hingis retired in November 2007 after being hampered by a hip injury for several months.
Are there any other interesting aspects about Martina Hingis?
Martina Hingis briefly ended her coaching relationship with her mother Melanie early in the year 2001 but had a change of heart two months later just before the French Open.

Question: Why did she end her coaching relationship?
Self-contained rewrite: Why did Martina Hingis end her coaching relationship with her mother?