The Australian mixed martial arts community is mourning the loss of Jake Sendler, who has died at just 21 years old due to a rare muscle condition linked to excessive exercise.
Sendler was rushed to hospital after competing at an MMA event in Melbourne on March 3, where witnesses reported he displayed erratic behavior. Despite medical intervention including an induced coma, multiple surgeries, and blood transfusions, Sendler passed away on Wednesday.
Medical professionals determined Sendler was suffering from rhabdomyolysis, a potentially fatal condition where muscles break down due to overexertion, underlying health conditions, or trauma. The condition causes disintegrated muscle fibers and toxins to enter the bloodstream, which can lead to kidney failure.
According to sources within the MMA industry, Sendler was attempting to lose a significant amount of weight before his competition. “He told people he trained with on the Friday before the fight, approximately 48 hours before stepping into the ring, that he still had five to six kilos to drop,” an insider revealed to News Corp. “Given that he typically weighs around 75kg, that means he was attempting to lose nearly seven per cent of his total body weight in two days.”
Remarkably, despite his deteriorating condition, Sendler managed to compete for three full rounds in what would be his MMA debut.
A GoFundMe page established for Sendler described him as a warrior whose spirit remains unbroken: “With profound sadness, we share the heartbreaking news that Jake has passed away. Jake was not only a fighter in the MMA ring but also a true warrior in life,” the page reads.
“While preparing for an upcoming fight, Jake unknowingly pushed through worsening symptoms [of rhabdomyolysis]. He continued training, working, and coaching, unaware that his body was shutting down. Astonishingly, even as his organs were failing, Jake stepped into the ring one final time and fought courageously, demonstrating incredible determination and strength.”
The page noted that doctors described Sendler’s case as “the most severe case of rhabdo” they had ever encountered.
Sendler aspired to become a PE teacher and leaves behind an older brother, younger sister, and his partner Angela.
His devastated mother, Sharone, shared an important message for other athletes: “Jake was an absolute warrior, such a good man. He would never want this to happen to anyone. Our message is to listen to your bodies, but keep being great and follow your dreams.”
She revealed that Jake had experienced muscle pain and dark-colored urine—both symptoms of rhabdomyolysis—before the competition. “Jake, because he works so hard, he put those things down to him training so much,” she explained. “He went into that ring and gave everything like he was already suffering. So we know now that his body had already given in and his kidneys were already at 40 per cent. And he fought the three rounds.”
Rhabdomyolysis has affected other athletes in combat sports. Recently, 22-year-old Brazilian Jiu-Jitsu competitor Daniel Manasoiu revealed his own battle with the condition. Manasoiu, who won bronze at the 2024 ADCC World Championships, attributed his diagnosis to overtraining.
Medical experts warn that athletes in intense training regimens should be vigilant about symptoms including muscle pain, weakness, and changes in urine color, as early intervention for rhabdomyolysis can be lifesaving.
