Sprint sensation Usain Bolt etched his name in the Olympic record books by completing a golden treble, as he powered the Jamaican relay team to the gold medal.

Meanwhile, Ehiopian Tirunesh Dibaba claimed an unprecedented long distance double by winning the women's 5000 m event in Beijing on Friday.

The 22-year-old Bolt, who had set the track ablaze by winning the 100 m and 200 m sprint titles earlier, added a third gold to his kitty as the Jamaicans took the honour in the men's 4X100 m relay event with a world record timing of 37.10 sec.

There was no American representation in the relay events after both the men's and women's teams botched baton handovers in the heats, marking a nightmarish campaign for the formidable US track and field team.

Bolt, the first athlete in 24 years to win the gold in 100 m and 200 m events, ended his brilliant campaign in the Olympics on the victory podium in what has been a remarkable show by the lanky Jamaican.

With his teammates Nesta Carter, Michael Frater and Asafa Powell living upto expectations, the Jamaicans bettered the previous world record of 37.40 sec. But the Jamaican women's relay team, billed as the favourites, quite shockingly dropped the baton to fritter away a definite chance of a medal.

While the Jamaican men's relay team hogged the spotlight, Dibaba also had her share of glory by clinching the gold in the women's 5000 run.

Maurren Maggi of Brazil won the women's long jump with a best effort of 7.04 m. The 32-year-old took the coveted gold medal ahead of defending champion Tatiana Lebedeva of Russia (7.03m), while Nigerian Blessing Okagbare was third with 6.91m.

Alex Schwazer of Italy won the men's 50 km walk to deny Russia a cleansweep of the Olympic titles gruelling event.

The 23-year-old two time world medallist broke the 20 year-old Olympic record as he timed 3 hr:37.09 to take gold ahead of Jared Tallent of Australia, who had a personal best of 3hr 39:27, while Russian number one Denis Nizhegorodov won the bronze in 3hr 40.14.

With just two days left for the curtains to come down on the sporting extravaganza, hosts China maintained their position atop the medals table with an umpressive tally of 46 gold, 15 silver and 22 bronze medals for an overall haul of 83 medals.

The USA were in the second position with a tally of 30-35-35 while Great Britain occupied the third position with 18-12-11. Russia kept themselves in the fourth position with a tally of 16-16-21.

The International Olympic Committee, meanwhile, completed the formality of stripping Ukraine's heptathlete Lyudmila Blonska of her silver medal after her B sample also turned out to be positive.

In another interesting development, The IOC also ordered an investigation into alleged age-fixing of Chinese gymnasts.

"We have asked the gymastics federation to look into what have been a number of questions and apparent discrepencies on this subject," said IOC spokeswoman Giselle Davies.