It's hard to make the Olympic team for your country as an able-bodied athlete. Imagine trying to accomplish that same feat but as a physically disabled athlete. Disabled is a misleading word as these athletes portrayed below are very able.
Oscar Pistorius, a double amputee South African, made headlines in his attempts to qualify for the Beijing Olympics in the 400m track event. While this was happening Natalie du Toit qualified for both the Olympic and Paralymic Games in marathon swimming and Natalia Partyka of Poland qualified in team table tennis.
I watched a documentary about Oscar while he went through testing monitored by the International Association of Athletics Federation (IAAF). The IAAF believed his carbon fiber prosthetics gave him an advantage over able-bodied runners. They tested the amount of energy the blades returned when hitting the ground as compared to the foot of an able-bodied runner and concluded Oscar had an advantage. Oscar took his case to the Court of Arbitration for Sport and won. Had Oscar met the Olympic qualifying time, he would have been able to compete in Beijing.
Natalie was a national team swimmer who narrowly missed qualifying for the Sydney Games as a 16-year old. In 2001 her left leg was amputed at the knee after a car crashed into her scooter. A year later she became the first disabled athlete to compete in the 800m freestyle at the 2002 Commonwealth Games where she finished 8th. In Beijing she competed in the 10K swim and finished 16th. She was also given the honour of carrying the South African flag during the opening ceremonies.
Natalia competed in the team table tennis event in Beijing. Despite being born with a right arm that ends just below elbow, she regularly competes with and beats able-bodied competitors. Her team did not qualify for the play-off rounds.
There have been athletes with physical disabilities who have competed in previous Olympics.
American Marla Runyan, who is legally blind, finished 8th in the 1500m 2000 Sydney Olympics. She also competed in the 2004 Athens Games. It's hard enough for athletes to deal with the close proximity of runners and all the jostling – imagine being legally blind and doing that.
American Jim Abbott, who was born without a right hand, was the winning pitcher in the 1988 gold medal baseball match. After the Games he bypassed the minors and made his professional debut with the California Angles, winning 12 games in his rookie year. Jim played for 10 years in Major League Baseball.