BERLIN -- Two-time Olympic swimming gold medalist Britta Steffen of Germany has announced her retirement.
The 29-year-old Steffen won the 50-meter and 100-meter freestyle at the 2008 Beijing Olympics.
She says in a statement Friday that she is ending her career "in the knowledge of being one of the best in the world."
Steffen says she no longer has the "necessary motivation and energy" to continue competing for medals.
Steffen followed her Olympic wins in Beijing with world championship gold medals in the same events a year later in Rome.