The Australian mixed martial arts (MMA) world is grieving the loss of 21-year-old fighter Jake Sendler, who tragically passed away after a fight on March 3, 2025.
The Melbourne native had been rushed to the hospital immediately following the bout, and despite undergoing numerous surgeries and blood transfusions, his condition worsened, leading to his death.
The Fight and His Struggle
Sendler’s passing was the result of a rare muscle injury known as rhabdomyolysis, a condition that occurs when muscle fibers break down due to excessive strain, injury, or trauma.
These damaged muscles release toxins into the bloodstream, which can lead to kidney failure.
It was revealed that in the days leading up to his fight, Sendler had been attempting to lose a dangerous amount of weight—up to 7% of his body weight—in just two days.
A source close to Sendler reported that just 48 hours before stepping into the ring, he was still trying to shed 5 to 6 kilos, a massive amount considering his usual weight was around 75kg.
Unfortunately, his body was pushed too far, and the toll of overexertion led to his fatal condition.
A Warrior in Life and Death
A heartfelt GoFundMe tribute was set up in Sendler’s honor, remembering him not only as a fighter but as a beloved coach, son, and friend.
The message described him as a “true warrior” who never gave up, even when his body was shutting down.
Despite worsening symptoms of rhabdomyolysis, Sendler continued to train, coach, and compete, unaware that his organs were failing.
After the fight, his condition rapidly deteriorated, and he was rushed to the hospital where doctors fought to save him, but ultimately he passed away after days of battling with bravery.
A Lasting Legacy of Determination and Strength
Sendler’s Instagram is filled with moments that reflect his passion for fighting and his commitment to pushing past limits.
In one post, he celebrated a knockout win, captioning it, “Train hard, fight easy,” while another post showed his victory with the words, “Thank you to my coaches and teammates for always pushing me past my limits.”
His mother, Sharone, expressed the family’s heartache, remembering Jake as an “absolute warrior” and emphasizing the importance of listening to one’s body.
She shared that in the lead-up to the fight, Jake had muscle pain and dark urine—two common symptoms of rhabdomyolysis—but he attributed these to the intensity of his training.
“He went into that ring and gave everything like he was already suffering,” his mother said, revealing that his kidneys were already at 40% capacity by the time he fought the three rounds.
Jake’s Aspiration and Family
Sendler, who aspired to become a PE teacher, leaves behind a grieving family, including his older brother, younger sister, and partner Angela.
His story serves as a powerful reminder of the physical risks athletes face and the importance of self-awareness when pushing the limits of endurance.
In his memory, his mother shared a final message: “Our message is to listen to your bodies, but keep being great and follow your dreams.”
Though Jake’s body may have failed him, his spirit remains an inspiration to all who knew him.