Olympics day seven preview

Asafa Powell and Usain Bolt go head to head in the 100m

Jamaica's Usain Bolt and Asafa Powell begin their quest for men's 100m gold on Friday (0200 BST) as the athletics programme starts in the Bird's Nest.

The track cycling also gets under way at the Laoshan velodrome, with Great Britain's Chris Hoy in action.

He joins forces with Jamie Staff, Ross Edgar and Jason Kenny in the men's team sprint, with heats from 0930 BST.

American swimmer Michael Phelps goes for his sixth gold of the Games in the 200m individual medley at 0345 BST.

Bolt is the hot favourite for the prized 100m gold medal after breaking compatriot Powell's world record by running 9.72 seconds in May.

And he is in a confident mood ahead of Friday's qualifiers, although he faces stiff competition from Powell as well as US sprinter Tyson Gay.

"I'm in good form and everything is going well,� said Bolt, who will double up in the 200m.

Britain's challenge in the 100m comes in the shape of Simeon Williamson, Craig Pickering and Tyrone Edgar, all of whom will be targeting a place in the final as a realistic achievement.

Britain's Kelly Sotherton begins her heptathlon campaign, with Jo Pavey and Kate Reed in 10,000m action.

The golden girl of British athletics, Sotherton has been in mixed form ahead of her challenge in the heptathlon.

Sotherton, who won bronze in Athens four years ago, has been working hard to improve her javelin which in the past as been an area of particular weakness.

The 31-year-old recognises that an improved javelin performance could be the secret behind winning gold, and she feels that significant progress has been made.

"I always get criticised for it (the javelin) being bad, and it is bad, but can't they recognise the progress I'm making? If people can't recognise that progress then they're blind," Sotherton said.

"It's not a physical problem, its a mental one. The more of a point people make about it, the more I struggle."

Pavey and Read go in the final of the women's 10,000m at 1545 BST, with Pavey in particularly good form ahead of Friday's action.

Michael Phelps goes for his sixth gold medal on Friday

At the velodrome, Team GB's cycling quartet are among the favourites for gold but will face stiff competition from France, who beat them at the World Championships in March.

The men's team sprint is the pick of the action but there is also qualifying in the men and women's individual pursuit to look out for.

In the Water Cube, British swimmer Mark Foster goes in the 50m freestyle semi-final but Phelps is again the main attraction in the pool.

Phelps could move a step closer to Mark Spitz's 1972 record of seven gold medals in an Olympic games with victory in the 200m individual. Day seven also sees the finals of the men's 200m backstroke, the women's 200m breaststroke and the women's 100m freestyle.

Welsh swimmer David Davies, who won bronze in Athens, starts his assault on Olympic glory in the heats of the men's 1500m freestyle.

Action in the tennis also reaches a key stage with both the men's and women's semi-finals as well as the men's doubles bronze match.

The men's archery (1037 BST) will come to a conclusion on Friday with Britain's Alan Wills expected to be in the mix for a medal, as will Jon Hammond in shooting's 50m rifle prone.

Karina Bryant goes in the +78kg judo preliminaries at 0500 BST while the women's all around gymnastic final gets underway at 0415 BST.