Beijing - Alex Schwarzer braved the heat to give Italy Olympic gold in the men's 50 kilometres walk on Friday for the first time in 44 years.

Germany and Belarus each grabbed two golds in the flatwater canoe and kayaking events, while Latvian Maris Strombergs and Anne-Caroline Chausson of France won the inaugural BMX cycling gold medals.

Todd Rogers and Philip Dalhausser of the United States took men's beach volleyball gold on a day when doping offender Lyudmila Blonska of Ukraine was stripped of her heptathlon silver medal and kicked out of the Beijing Games.

In the walk - taking place in merciless sunshine after Thursday's heavy rain - Schwarzer broke a three-man leader group after the 40km mark to claim victory in 3 hours 37 minutes 9 seconds.

Jared Tallent of Australia added the silver to his 20km bronze in a personal best 3:39:27, while Russia's Denis Nizhegorodov won bronze to go with 2004 Olympic silver in 3:40:14.

"It was relatively easy, though with the usual suffering. It went well ... The last lap outside the stadium was very emotional and when I entered the stadium my emotions were very high," said Schwarzer.

Schwarzer is the first Italian to win the walk marathon since Abdon Pamich 1964 in Tokyo. The last three editions were won by now retired Polish great Robert Korzeniowski.

Germany was successful in the women's kayak four 500m and the kayak two 1,000m at the Shunyi Olympic Rowing-Canoeing Park, while Briton Tim Brabants won the kayak single over 1,000m and Attila Sandor Vajda from Hungary took gold in the 1,000m canoe single.

There was joy for Belarus in the men's kayak over 1,000 metres as well as for Belarus pair Andrei Bahdanovich and Aliaksandr Bahdanovich in the men's 1,000m canoe.

In the inaugural BMX cycling, Strombergs won ahead of American duo Mike Day and Donny Robinson, finishing in 36.190 seconds, 0.416 seconds in front of Day.

Chausson won the women's event in a close finish against her teammate Laetitia le Corguille and American Jill Kintner. Pre-race favourite Shanaze Reade from Great Britain, crashed out in the final.

Rogers and Dalhausser beat Brazilian pair Marcio Araujo and Fabio Luiz Friday to take gold in men's beach volleyball in three sets, 23-21, 17-21, 15-4. Bronze went to Brazil's Ricardo Santos and Emanuel Rego who beat Brazilian-born Gergians Jorge Terceiro and Renato Gomes in straight sets, 21-15, 21-10.

Blonska, 30, tested positive for the steroid methyltestosterone after the completion of the heptathlon on August 16 where she finished second behind compatriot Natalya Dobrynska.

Blonska also faces a life ban from the ruling athletics body as she is a second-time offender.

Thai boxers Manus Boonjumnong and Somjit Jongjohor remain in the hunt for gold after winning their respective semi-finals.

Defending light welterweight champion Manus easily outscored Cuba's Roniel Iglesias Sotolongo, while flyweight Somjit was also impressive in his defeat of Italy's Vincenzo Picardi.

US hopes of claiming a gold were dashed with the defeat of heavyweight Deontay Wilder. Italian Russo Clemente proved too strong for Wilder, the last American left battling for an Olympic boxing medal.

Clemente, the 2007 world champion, meets Russia's Rakhim Chakhkiev in Sunday's final.

The International Olympic Committee meanwhile confirmed that it has requested gymnastics' ruling body FIG to look into whether any underage Chinese women gymnasts have competed at the Beijing Games.

There have been constant allegations that He Kexin, who won the uneven bars competition and was also a member of China's gold- winning team, was 14 rather than 16 as stated. There has also been controversy surrounding Jiang Yuyuan, who also took team gold.

Outside the sporting competition, Beijing police ordered six pro- Tibet activists - all Americans - to 10 days in detention in the harshest treatment so far of Tibet activists since a series of demonstrations in the capital during the Olympics.

Police said the six were arrested on Tuesday for "disturbing public order". They were believed to be the same six from the US- based group Students for a Free Tibet, which had held eight pro-Tibet protests in Beijing since August 6.