Dame Sarah Storey, Great Britain's most-decorated Paralympian, has retired from international competition with immediate effect.
The 48-year-old cyclist has opted not to compete at Los Angeles 2028 to focus on helping improve Para-sport.
The 19-time Paralympic champion feels the sport has "stalled somewhat" since the London 2012 Games and that many areas "still need attention".
"The years between each Games haven't been utilised well enough to create the momentum that I and others hoped to see," she said.
"I see this as a critical stage; there are many areas of Para-sport that still need attention, and that is something that has played a big part in my decision.
"I fully believe that I can have a greater impact off my bike, rather than chasing a 10th Games and possibly further titles.
"I'm excited to be part of a future where we inject the momentum that is needed to ensure the future is bright for all Para-athletes."
Storey started her career as a swimmer and competed at four Games before switching to cycling, winning a total of 30 Paralympic medals across nine Games, including four golds at London 2012.
World Athletics president Lord Coe, who was chairman of London's organising committee for the Olympic and Paralympic Games, said: "Para-sport was an enormously significant part of London 2012 and I remain extremely proud of what we were able to deliver.
"However, the issues that Dame Sarah raises upon her retirement resonate with me hugely - sport must continue to take those small but steady steps forward to ensure that what has gone before is not wasted."
The British Paralympic Association has been approached for comment.
Born without a functioning left hand, Storey began her Paralympic career as a 14-year-old swimmer in 1992 and won 16 medals in the pool across four Games, including five golds.
Having been unable to swim for much of 2005 due to ear infections, she started cycling and made a permanent switch before Beijing 2008, when she won the first of her 14 Paralympic cycling golds.
Baroness Tanni Grey-Thompson, who won 11 Paralympic gold medals for Great Britain in wheelchair racing, first met Storey at the Barcelona Paralympics in 1992.
"I always said that it felt a little bit like her swimming career was a stepping stone - she was good at swimming, but the sport that she was really good at was cycling," the Paralympic great told BBC 5 Live.
"There are very few athletes who manage to successfully talent transfer from one sport to another."
In 2010, Storey also became just the second Para-athlete to compete against non-disabled athletes at the Commonwealth Games, finishing sixth for England in the individual pursuit.
"I am so privileged to have spent 35 years as an international athlete," Storey said.
"I genuinely pinch myself that my childhood dream of being an athlete for as long as I possibly could has led to nine Paralympic Games and opportunities across so many sporting events.
"This has included women's and Para-sport alike, and I feel so proud to have contributed - alongside so many incredible people - to the progress we've all witnessed and enjoyed in that time."
The 48-year-old cyclist has opted not to compete at Los Angeles 2028 to focus on helping improve Para-sport.
The 19-time Paralympic champion feels the sport has "stalled somewhat" since the London 2012 Games and that many areas "still need attention".
"The years between each Games haven't been utilised well enough to create the momentum that I and others hoped to see," she said.
"I see this as a critical stage; there are many areas of Para-sport that still need attention, and that is something that has played a big part in my decision.
"I fully believe that I can have a greater impact off my bike, rather than chasing a 10th Games and possibly further titles.
"I'm excited to be part of a future where we inject the momentum that is needed to ensure the future is bright for all Para-athletes."
Storey started her career as a swimmer and competed at four Games before switching to cycling, winning a total of 30 Paralympic medals across nine Games, including four golds at London 2012.
World Athletics president Lord Coe, who was chairman of London's organising committee for the Olympic and Paralympic Games, said: "Para-sport was an enormously significant part of London 2012 and I remain extremely proud of what we were able to deliver.
"However, the issues that Dame Sarah raises upon her retirement resonate with me hugely - sport must continue to take those small but steady steps forward to ensure that what has gone before is not wasted."
The British Paralympic Association has been approached for comment.
Born without a functioning left hand, Storey began her Paralympic career as a 14-year-old swimmer in 1992 and won 16 medals in the pool across four Games, including five golds.
Having been unable to swim for much of 2005 due to ear infections, she started cycling and made a permanent switch before Beijing 2008, when she won the first of her 14 Paralympic cycling golds.
Baroness Tanni Grey-Thompson, who won 11 Paralympic gold medals for Great Britain in wheelchair racing, first met Storey at the Barcelona Paralympics in 1992.
"I always said that it felt a little bit like her swimming career was a stepping stone - she was good at swimming, but the sport that she was really good at was cycling," the Paralympic great told BBC 5 Live.
"There are very few athletes who manage to successfully talent transfer from one sport to another."
In 2010, Storey also became just the second Para-athlete to compete against non-disabled athletes at the Commonwealth Games, finishing sixth for England in the individual pursuit.
"I am so privileged to have spent 35 years as an international athlete," Storey said.
"I genuinely pinch myself that my childhood dream of being an athlete for as long as I possibly could has led to nine Paralympic Games and opportunities across so many sporting events.
"This has included women's and Para-sport alike, and I feel so proud to have contributed - alongside so many incredible people - to the progress we've all witnessed and enjoyed in that time."
