TOKYO: Sport climbing debuts at the Olympics next month in a controversial combined format requiring athletes to excel in three radically different disciplines to secure a single gold medal on offer to each gender.

Athletes compete across three disciplines: speed, which is a vertical sprint, bouldering, which requires power and problem solving, and lead climbing, a test of endurance.

Gold will go to the climber with the lowest combined score, a multiplication of their rankings in each of the three disciplines.

Medal limits imposed by the International Olympic Committee (IOC) at climbing's first Games led to the decision to combine disciplines to ensure maximum exposure for the fast-growing sport, although that in turn means some of the world's best climbers will not be appearing in Tokyo.

Even stand-out favourites like the Czech Republic's Adam Ondra will need to perform in weaker disciplines - in his case the head-to-head speed event - for a chance of gold.

The COVID-19 pandemic and its impact on training has also added to uncertainty.

"We are all new to this format, and we all are playing the game with very unpredictable results," Ondra said in a previous YouTube video. "I must say it makes it pretty exciting."

The sport's elite climbers are already showing results from pivoting to less familiar disciplines.

Miho Nonaka, a bouldering specialist and one of four Japanese contenders at the Games, took third place in speed at the climbing World Cup in Salt Lake City last month.

"As the only discipline where you compete against an opponent, I really understood that speed is not just about timing but that it's a psychological battle," said Nonaka on her YouTube channel.

Another Japanese athlete, Tomoa Narasaki, has also cut his speed time to 5.7 seconds, within striking distance of the 5.5 seconds recorded by France's Bassa Mawem, a speed veteran and the oldest climber at Tokyo 2020.

With 20 male and 20 female athletes competing and the format favouring all-rounders, some of the world's best climbers in their specialized disciplines were unable to qualify.

Speed hotspot Indonesia failed to secure a single climbing spot at the Games. One of that country's top climbers, Veddriq Leonardo, set a world speed record of 5.208 seconds at the Utah competition last month.

The setback may be temporary, however, with speed to be split from bouldering and lead climbing at Paris 2024, offering more opportunity for the sport's young athletes and greater potential for record-breaking times.