BEIJING — Natalie Du Toit of South Africa won her fourth gold medal in swimming at the Beijing Paralympics, taking the 400-meter freestyle on today in a world-record time for her disability group.

Du Toit, who lost a leg in a 2001 motorcycle crash, finished in 4 minutes, 43.81 seconds — 0.15 better than the mark she set three years ago in London.

One of two athletes in the Paralympics who also competed at the Beijing Olympics, Du Toit has set three disability group records in winning four golds. She also set records in the 100 butterfly and 200 individual medley. Her other gold came in the 100 freestyle, where she already holds the record.

She will wrap up her Paralympic program Sunday in the 50 freestyle, where she also holds the disability group record.

Du Toit won five golds and a silver at the Athens Paralympics, but chose to compete in only five events in Beijing. She said she could have done even better Friday.

"I had a really bad turn and had to stop and start again, which wasted a lot of energy," she said. "I didn't think I would do a best time."

Du Toit finished 16th at the Beijing Olympics in the 10-kilometer open-water swim. A promising Olympian until her injury, she's hoping to qualify for the 2012 London Games.

Fifty-four medals were up for grabs Friday. In the major disciplines, there were 16 in swimming, 15 in cycling and 18 in track and field. Spain won three golds in swimming to lead all countries.

Britain dominated cycling with four gold medals and six overall. The United States won seven medals in cycling, including three gold. Spain also managed three gold medals in cycling and six overall.

In track, sprinter Oscar Pistorius is expected to win the 200 on Saturday, adding to the gold he won earlier in the week in the 100.

In the medal standings, China leads with 37 gold and 109 overall. Britain has 33 gold and 69 overall, followed by the United States with 23 and 56 overall.