Joe Choong is set to quit modern pentathlon after defending his Olympic title next year, expecting to be part of a widespread exodus amid a controversial change being pushed through.

A decision by the International Modern Pentathlon Union to replace show jumping with obstacle course racing was endorsed by national federations but caused dismay among athletes, including Choong.

The new structure of the sport – also comprising fencing, swimming and a combined running and shooting event – is awaiting the International Olympic Committee’s approval for inclusion at the 2028 Games.

But Choong, alarmed at how the switch has been handled by the sport’s governing body, is resigned for his swansong to be at Paris 2024 – and the 28-year-old suspects he will not be alone in walking away.

He told the PA news agency: “Paris will be a great way to round off my career because I expect it will be the last time I compete in pentathlon. I think there will be a mass walkout from the sport.

“We’re not just talking about people my age who are in their mid-to-late 20s, but 21 or 22-year-olds will suddenly see this chance to go to an Olympics as their last chance before they decide to retire.

“I think that’s the feeling amongst the community and it will be hard to see where the sport goes, what the next top athlete looks like with obstacle course racing in the picture.

“The athletes’ voice as a whole was pretty much completely ignored. The politics pushed through whatever they wanted. After Paris, we’ll see what happens but I don’t think I’ll be taking part in it.”

Modern pentathlon’s image was rocked two years ago when a German coach was witnessed punching a horse that refused to jump a fence at the Tokyo Games, prompting the removal of equestrianism by the UIPM.

Show jumping remains one of the events for Paris 2024 but modern pentathlon faces a battle to be included at the 2028 Games in Los Angeles, with the UIPM admitting the sport needs to modernise.

Choong, who in Tokyo became the first British male to win individual Olympic gold in the modern pentathlon, accepted some rules could be modified so the sport becomes a “bit snappier”.

But such is his opposition to the proposed changes, Choong has thought about swapping lanes.

He said: “I would definitely want to stay competitive at something. Fencing is something I’ve dipped my toes in slightly over the last two years.

“That’s partly been an effort to improve my fencing for pentathlon but at the same time, it’s like that addictive nature where I’m back to being one of the chasers, I’m not at the top of the sport anymore.

“It sounds weird but I absolutely loved coming 64th or something at one of my first competitions.

“I’ll definitely be going back to that and seeing if I can push the boundaries, slightly, on fencing or maybe one of the other sports in pentathlon and see how far I can push one of those sports compared to what’s expected of a normal pentathlete.”

Choong’s more immediate focus is on next month’s European Games in Krakow, where he could complete his gold medals haul after adding to his Olympic success by triumphing at last year’s World Championships.

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Choong admitted fulfilling a life goal in Tokyo meant he struggled to adjust afterwards but the prospect of competing at a third Olympics next year is sharpening his focus.

He added: “You see people like Adam Peaty and Max Whitlock, they talk about having that hunger for the sport and sometimes it’s not quite there.

“I took a lot of time out after the Tokyo Games because you need a reset. To then go on and win the World Championships off the back of a slightly disjointed year almost compounded that feeling of ‘what’s next?’ and finding the why.

“Having had a couple of years to refocus, I’m very hungry to go and do it all again.”

The United States cut into China's lead in the medal table, leaving them just two ahead at the end of the penultimate day of the Tokyo Olympics.

China came into Saturday with a five-gold lead but double 4x400m relay success provided the platform for USA to make up ground.

Allyson Felix became the only American athlete to win 11 track medals as the women cruised to relay gold, while the men coasted to an 18th success as they finished well ahead, the Netherlands a distant second.

Team USA recorded their fourth successive gold in the men’s basketball final, plus there was success for Nelly Korda in the women's golf.

China picked up two golds to take their tally to 38, with Cao Yuan, who became the first athlete to win three different Olympic diving events, and Yang Jian securing a Chinese one-two in the 10m platform. Their other victory came in the women's canoe double 500m sprint.

Early leaders Japan collected a trio of triumphs, the first of which came in softball, while the Russian Olympic Committee also secured three golds, Abdulrashid Sadulaev dominating the men's heavyweight freestyle wrestling.

Galal Yafai captured Great Britain's 19th gold with a 4-1 points decision in the men's flyweight boxing final before Joe Choong added another by replicating Kate French's achievement in the men's version of the modern pentathlon.

Australia, who equalled their record medal haul at the Games on Thursday, remain in sixth place, Nicola McDermott's silver making history in the women's high jump with her country's first medal in the event since 1964.

Germany's modern pentathlon coach Kim Raisner has been disqualified from the Olympic Games after hitting a horse that refused to jump during the women's competition.

Early leader Annika Schleu's medal hopes were shattered on Friday when Saint Boy, the horse she was allocated for the show-jumping section of the five-discipline event, proved unwilling to perform.

It led to Schleu being reduced to tears while still on board the seemingly agitated horse as her prospects of success slipped away.

Raisner suggested Schleu hit the horse to jolt it into action, before striking it herself near its rear left leg.

Modern pentathlon's world governing body, the UIPM said on Saturday its executive board (EB) had "given a black card to the Germany team coach Kim Raisner, disqualifying her from the remainder of the Tokyo 2020 Olympic Games".

"The EB reviewed video footage that showed Ms Raisner appearing to strike the horse Saint Boy, ridden by Annika Schleu, with her fist during the riding discipline of the women's modern pentathlon competition," the UIPM added in a statement.

"Her actions were deemed to be in violation of the UIPM competition rules, which are applied to all recognised modern pentathlon competitions including the Olympic Games.

"The EB decision was made today at the Tokyo Stadium before the resumption of the men's modern pentathlon competition."

That meant Raisner was not present as Germany competed on Saturday, with Patrick Dogue finishing second in the show-jumping stage in her absence.

Germany's modern pentathlon federation, the DVMF, promised an investigation.

Modern pentathlon competitors are presented with horses for the show-jumping element, and have 20 minutes to become acquainted before they must ride.

"It goes without saying that there will be a comprehensive and critical evaluation of what happened after the Olympic Games," the DVMF said.

"The DVMF also makes it clear that the welfare of the horses is the unreserved concern of the association."

China remain atop the Olympics Games medal table as they maintained their five-gold buffer over the United States with two on Friday in Tokyo.

The table-toppers head into the penultimate day at the Olympics with their advantage still intact, courtesy of gold in the women's javelin and the men's team table tennis.

Shiying Liu became the first Asian woman to win gold in the javelin, while China extended their perfect record in table tennis since its 2008 introduction – Ma Long becoming the most decorated table tennis Olympian with his fifth triumph.

USA matched China's gold count on day 14, collecting the top spot in the women's beach volleyball and via Gable Steveson's last-second victory in the men's superheavyweight freestyle wrestling.

Japan remain in third place and collected two golds, the first of which came in the women's featherweight freestyle wrestling from Mayu Mukaida with the second following through three-time world champion Ryo Kiyuna, who was crowned the first ever men's kata karate Olympic champion.

After falling down to sixth on Thursday, Great Britain bounced back up to fourth with a pair of golds. Laura Kenny teamed up with Katie Archibald to become the first British female Olympian to triumph at three consecutive Games – winning the women's madison comfortably.

Kate French captured Team GB's other gold in the women's pentathlon, though there could have been a third had the men's 4x100 metre relay team not been pipped at the line by Marcell Jacobs' Italy.

The Russian Olympic Committee sit in fifth on 17 golds, Zaurbek Sidakov securing their sole gold of the day in the men's welterweight freestyle wrestling.

After firing a blank on Friday, Australia – who equalled their best ever medal haul at the Games a day earlier – dropped down to sixth, level with the Russians on 17 golds.