The online Congress due to be held tomorrow and on Sunday (November 13) is set to feature a vote on a UIPM Executive Board proposal for obstacle to become modern pentathlon's fifth discipline after Paris 2024, following the move to axe equestrian last year.

Advocates have argued that this would make the sport more accessible, and should avoid a repeat of the upsetting scenes of Tokyo 2020, where German coach Kim Raisner was sent home in disgrace for punching a horse that refused to jump during the women's competition.

The UIPM has pointed to its data showing an 88 per cent satisfaction with the overall experience at obstacle test events among pentathletes, but the findings have been disputed by those who favour preserving a reformed version of equestrian.

The Pentathlon United pressure group, which includes Briton Choong among its supporters, has spearheaded opposition, claiming that the changes contradict the prevailing will of athletes and highlighting its survey in which 92 per cent of respondents favoured keeping riding.

Choong is joined by 54 current and former athletes in the sport - including compatriot French - in writing to IOC sports director Kit McConnell and Athletes' Commission chair Emma Terho to ask for the Lausanne-based organisation to help ensure that the athletes' voice is represented in the sport.

"The sport needs to set aside the last twelve months and form a new athlete-centred commission to properly explore the reforms needed for Modern Pentathlon to satisfy the IOC's inclusion criteria, retaining its 5 current disciplines," the letter, seen by insidethegames, reads.

"We ask for the IOC to help facilitate this commission.

"It cannot be led by the UIPM as it has demonstrated it cannot be an honest broker.

"It needs an independent arbiter, respected by all and understanding all views.

"The commission must focus on reforming our sport, while maintaining the integrity of our five disciplines.

"Time is of the essence.

"We would be grateful for an urgent response, indicating your willingness to consider this request."

The letter also alleges that the online format of the Congress will "significantly limit democratic dialogue".

The UIPM insists that it would be unfair to stage an in-person or hybrid event due to the prohibitive costs involved.

Choong and the other athletes also claim that long-serving UIPM President Klaus Schormann "was unavailable to meet our movement of athletes, Pentathlon United before Congress", reference surveys suggesting that a majority of athletes wish for riding to remain the sport, and accuse the UIPM Athletes Committee of being "set to vote against the overriding will of its own constituents".

They argue that a reformed version of the sport including equestrian can satisfy the IOC's inclusion criteria for Los Angeles 2028, where the sport has been left off the initial programme.

Schormann, who has led the UIPM since 1993, has rejected the suggestion that the UIPM has ignored the will of athletes and played down the degree of opposition.

He has argued that riding is outdated in modern pentathlon, and has cited a desire to "be more fair to the athletes, to give them opportunities to start, not only European nations with horses".

However, the move to axe riding has prompted calls for Schormann to step down by supporters of the equestrian discipline, with a motion of no confidence set to be voted on at the Congress and Australian Alex Watson recently announcing his hopes of ousting the German official.

Other signatories of the letter to the IOC include Britain's Sydney 2000 bronze medallist Kate Allenby, a key voice within Pentathlon United, Rio 2016 silver medallist Pavlo Tymoshchenko of Ukraine and London 2012 bronze medallist Adam Marosi of Hungary.

Ten Czech athletes, 10 Hungarian athletes and 12 Ukrainians are among the signatories.

Athletes from France, Britain, Ireland, Poland, Spain and the United States also feature.

insidethegames has asked the IOC and UIPM for comment.