South Africa's Natalie du Toit won five gold medals and a silver four years ago at the Athens Paralympics. (Michael Kappeler/AFP/Getty Images)

A total of 4,000 athletes from 150 countries will be competing in 20 sports when competition for the Paralympics begins Sunday.

Over the course of the 10-day competition in Beijing, a number of elite athletes are expected to challenge for several world records and gold medals.

Here are 10 international competitors who should have an impact:

Natalie du Toit, South Africa (Swimming) — Du Toit will be one of the more amazing stories at the Paralympic Games. A motorcycle accident in 2001 forced amputation of her left leg at the knee. However, that didn't stop the 28-year-old swimmer from finishing 16th in the women's 10-kilometre marathon at the Beijing Olympics that ended Aug. 24. Du Toit, who won five gold medals and a silver at the Athens Paralympics, also placed fourth during the 2008 world championships in the 10-km event.

Oscar Pistorius, South Africa (Athletics) — The double-amputee sprinter failed in his bid to qualify against able-bodied athletes at the Beijing Olympics, but this setback won't dampen his resiliency. Four years ago in Athens, Pistorius qualified for the final of the 200 metres despite falling in the preliminary round. He then went on to win gold by breaking the world record in 21.97 seconds.

Ernst van Dyk, South Africa (Wheelchair racer) — Van Dyk has won more Boston Marathons (seven) than any other male wheelchair athlete. The South African claimed sixth straight Boston Marathons from 2001-2006, and his world-record effort four years ago still stands. Van Dyk is a four-time Paralympic medallist, including three at the 2004 Athens Games.

David Weir, Great Britain (Wheelchair racer) — Weir heads into the Beijing Paralympics as one of the hottest athletes. The four-time London Marathon champion and world-record holder in the 400 won two gold medals at the Paralympic World Cup event in May, and is considered one of the best wheelchair athletes in the world. Weir is targeting to reach the top of the podium in five events in Beijing.

Marcel Hug, Switzerland (Wheelchair racer) — Hug has competed against Weir several times and remains a medal threat for Beijing. The Swiss athlete won two Paralympic bronze medals four years ago in the 800 (European record) and the 1,500 events.

Darren Kenny, Great Britain (Cycling) — A win at the national disabled Circuit Champs convinced officials to invite Kenny on the Paralympic team for 2004. The Brit justified the selection by winning two gold medals in the men's open 1-km time trial and 3-km individual pursuit. Kenny also holds all five track world records for his class.

James Anderson, Scotland (Swimming) — The 45-year-old Broxburn native is competing in his fifth Paralympic Games and is one of the most successful Paralympic athletes Scotland has ever produced. Anderson won gold medals in all four of his events in Athens, and has set two world records and four European records during his career.

Tim Prendergast (Athletics), New Zealand — Prendergast was chosen as New Zealand's team captain for the Beijing Paralympics. The middle-distance runner won a gold medal in the men's 800 at the Athens Games and still competes against athletes with full vision. In 2007, Prendergast finished seventh at the 2007 New Zealand National Athletics competition.

Eliza Stankovich, Australia (Wheelchair racer) — Competing in her first Paralympics four years ago, Stankovich raced to a silver in the 800 after finishing 18/100th of a second behind Canadian icon Chantal Petitclerc. Less than a year later, Stankovich claimed another silver at the inaugural Paralympics World Cup in Manchester, England, as she once again placed second to Petitclerc in the women's 200.

Zhang Liping, China (Powerlifting) — Zhang was first introduced to the sport of powerlifting at age 30 by her coach and won a silver medal at the Athens Paralympics. She continued her rise in June 2007, where she won a gold medal in the 82.5-kg division at the European championships by breaking a world record with a lift of 143.5 kg.