Her physical condition deteriorates slowly, as her skeletal muscles weaken and degenerate progressively, but is expected to stabilise when she reaches the age of 20.
Her fist-like hands and weak wrists cannot catch much water, and so cannot propel her like boat oars. Thus, she compensates with super-fast strokes.
Yip's head is also tilted back and submerged, so that her hips can rise higher in the water, reducing the drag created by her limp legs.
Paralympics: Singapore swimmer Yip clinches gold in 50m backstroke
15 September 2008 1838 hrs (SST)
SINGAPORE: Swimmer Yip Pin Xiu has won the first gold medal for Singapore at the Beijing Paralympics in the 50-metre backstroke finals.
She clocked 58.75 seconds, way ahead of Britain's Fran Williamson who clinched the silver in 1:06.07.
Yip broke her own world record during the heats earlier Monday. She clocked a new world and Paralympic record time of 57.92 seconds. Fran Williamson was second with a time of one minute 6.75 seconds.
Yip on Saturday clinched Singapore's first silver at the Paralympics, in the women's 50-metre freestyle finals. Despite not coming in first in the finals, she maintains the new world and Paralympic record she set in the heats earlier on Saturday, with a timing of 57.04 seconds.
Yip will receive S$100,000 for her gold medal under the Athletes Achievement Award (AAA) set up by the Singapore National Paralympic Council.
However, fellow swimmer Theresa Goh finished empty-handed at the Paralympics. She failed to qualify for the 50-metre freestyle final, coming in last in her heat.
Singapore has won four medals in the Beijing Paralympics. Rider Laurentia Tan aced two bronze medals in equestrian.
The Paralympics ends on Wednesday.