By Pritha Sarkar

RIO DE JANEIRO (Reuters) - With their graceful lines and soaring tumbles, Kohei Uchimura and Gabby Douglas will be attempting to pull off a feat in the Rio Games that no gymnast has accomplished in over 40 years -- capturing back-to-back all-around Olympic golds.

After collecting every Olympic and world all-around title since taking silver at the 2008 Beijing Games, the man known as 'Super-mura' will be favorite to become the first man since Japanese compatriot Sawao Kato in 1972 to win successive Olympic titles in the event that tests skills across six apparatus.

For Douglas, though, things are not as clear cut.

Since Douglas' success in London, Simone Biles has turned into a one-woman demolition squad -- crushing anyone who comes before her with her explosive tumbles as she became the first woman to win a three-peat of all-around golds at the worlds.

She is such an unstoppable force that in just three years she has become the most successful female gymnast at the worlds with a haul of 10 golds.

That is the kind of opposition that Douglas needs to overcome to become only the third woman, after Russia's Larisa Latynina (1956-60) and Czech Vera Caslavska (1964-68), to win back-to-back all around titles.

''In terms of Gabby Douglas and Kohei Uchimura, both are capable of winning gold medals in Rio,'' Latynina, whose record of winning 18 Olympic medals was surpassed by swimmer Michael Phelps four years ago, told Reuters.

''I am amazed by the physical preparation that Douglas is showing and the level of skill that Uchimura shows.

''However, I don’t think they have much chance of winning 18 Olympic medals,'' she added, breaking down in laughter.

While Latynina's record of being the most successful gymnast is not under threat, Biles could become the first female gymnast to win five golds at a single Games as she collected four golds and a minor medal at each of the last two world championships.

Before any individual golds can be won, collective national pride will be on the line. Japan will be looking to end China's Olympic dominance in the men's team final on Monday while the U.S. women will be out to maintain their supremacy a day later as they are unbeaten in every global meet since 2011 - winning three successive world titles and the 2012 Olympic gold.

''The Americans are phenomenal. They’ve been dominating the sport now for over a decade. I don't really think they have any competition for the team gold as they've been winning every world championships by leaps and bounds for a long time,'' 1996 Olympic champion Kerri Strug told Reuters.

''It's exciting on one level that USA gymnastics has come so far but in terms of watching the competition, it's not exciting because we are so much better than everyone else.''

The collective strength of China means that since 1994, Chinese men have won 10 of 12 world championship team titles and three of the five Olympic golds on offer.

Japan, who captured five straight Olympic golds from 1960 to 1976, did climb to the top of the podium in Athens in 2004 but that was during the pre-Uchimura era.

Since Uchimura's arrival on the world stage, Japan have had to make do with silver medals behind champions China in 2008 and 2012.

But having finally toppled China from their lofty perch at last year's world championships in Glasgow, Uchimura hopes he can now lead his band of Japanese brothers to Rio glory.

''All I can think about is how much I want team gold. That's everything,'' Uchimura, who owns a record six successive world all around golds, told Reuters.

(Reporting by Pritha Sarkar, editing by Neil Robinson)