SINGAPORE (AFP) The Commonwealth Games athletics programme has been hard hit by a slew of top names pulling out, including Usain Bolt and Asafa Powell, leaving the event thin on star power. Bolt has shut down his season early to prevent an injury after tightness in his lower back, dealing a major blow to under-pressure organisers. The Jamaican, who won the 100m and 200m gold medals in world record times at the Beijing Olympics, said he prefers to focus instead on next years world championships in South Korea and the London Olympics in 2012. His compatriot and arch-rival Powell will also be missing, opting not to defend the 100m title he won four years ago in Melbourne, citing the timing of the event late in the season. Other drawcards missing include Englands marathon world record holder Paula Radcliffe, who is pregnant, and world and European heptathlon champion Jessica Ennis. English Olympic 400m gold medallist Christine Ohuruogu, world triple jump champion Phillips Idowu and Australias world discus champion Dani Samuels all opted out amid health and security fears. Kenyas David Rudisha, who broke the world 13-year-old 800m mark in Berlin last month and smashed it for a second time a week later, is also skipping the event, citing fatigue.I believe I need time to rest and focus on next year, said the 21-year-old. He is joined on the sidelines by Kenyas Olympic mens 1500m champion Asbel Kiprop and womens world 10,000m champion Linet Masai. In their absence, the country will look to Olympic and world 3,000m steeplechase champion Brimin Kipruto and Olympic womens 1500m champion Nancy Jebet Lagat to earn them gold. While many top names are missing, South Africas scandal-hit world 800m champion Caster Semenya takes part to boost her comeback after the sex test ordeal that saw her barred from competition. It will be the first major international event for the 19-year-old since being cleared to compete by the sports governing body following an inquiry into her gender that saw her sidelined for almost 11 months. We have observed her progress closely since the IAAF cleared her to run and its good to hear her say that shes focusing all her efforts on the Commonwealth, said Gideon Sam, president of the South African Sports Confederation and Olympic Committee. Her manager Tshepo Seema added: We are focused on working hard to improve her times and we are confident that we will bring back the gold medal from India. Since her return, Semenya has clocked sub-two minutes but has yet to match the 1:55.45 that won her the world title last year. Also making the South African squad are Olympic long-jump silver medallist Khotso Mokoena, Commonwealth champions Elizna Naude (discus), Sunette Viljoen (javelin) and LJ van Zyl (400m hurdles). Australia, which won 16 gold, 12 silver and 13 bronze medals in track and field at Melbourne in 2006, has a 57-strong team, spearheaded by Commonwealth, Olympic and world pole vault champion Steve Hooker. The Australian mens and womens 4x400m relay teams will also defend their titles while Tamsyn Lewis (4x400m relay) has been picked for her fifth Commonwealth squad. England too have an experienced squad including newly-crowned European 110m hurdles champion Andy Turner. Hosts India are fielding 90 athletes, its biggest Commonwealth Games squad, but few are expected to medal, with mens discus thrower Vikas Gowda and the womens discus trio of Krishna Poonia, Harwant Kaur and Seema Antil their best bet.