The Australian mixed martial arts community is mourning fighter Jake Sendler, who has died aged just 21 due to a rare muscle injury that’s been linked to excessive exercise.
Sendler was rushed to hospital after his bout at a fight night in Melbourne on March 3, during which he was reportedly seen behaving erratically.
He was placed in an induced coma and had multiple surgeries and blood transfusions, but could not be saved and passed away on Wednesday.
It emerged that the Melburnian was suffering from rhabdomyolysis, a condition that sees muscles break down due to overexertion, an underlying health condition or trauma.
The disintegrated muscle fibres and toxins enter the bloodstream and can cause kidney failure.
A member of the fight industry claimed Sendler had to drop a dangerous amount of weight before the bout.
Jake Sendler (pictured with partner Angela) collapsed during a fight on March 3 and died on Wednesday after multiple surgeries and blood transfusions

The 21-year-old (pictured left after winning a bout) somehow managed to fight for three rounds in his MMA debut despite suffering from a deadly muscle condition
‘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,’ the insider told 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.’
A GoFundMe page set up for Sendler remembered 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,’ it read.
‘A dedicated athlete, compassionate coach, beloved son, brother, and friend, Jake’s generous heart, boundless energy, and unwavering support deeply touched everyone who knew him.
‘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.
‘Immediately afterward, his condition rapidly deteriorated, leading to emergency hospitalisation and multi-organ failure—the most severe case of rhabdo his doctors had ever encountered.
Sendler is being remembered as a ‘true warrior in life’ by the grief-stricken Aussie fight scene
A fight industry insider has claimed Sendler (pictured with partner Angela) was trying to drop a large amount of weight before his last fight
Sendler’s mother pleaded with other fighters to listen to their bodies after her son fought through symptoms of the condition that killed him
‘Despite extraordinary medical efforts, including multiple surgeries and blood transfusions, Jake passed away after days of fighting with unmatched bravery.
‘Although his body succumbed, his resilient spirit remains forever unbroken.’
A post on Sendler’s Instagram shows him celebrating after winning a bout by knockout, with the caption ‘Train hard, fight easy’.
A second post showing him having his hand raised in victory is accompanied by the words, ‘Thank you to my coaches and teammates for always pushing me past my limits.’
Sendler aspired to become a PE teacher and leaves behind an older brother and younger sister, and his partner Angela.
‘Jake was an absolute warrior, such a good man,’ his devastated mother Sharone said.
‘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 added that Jake had muscle pain in the lead-up to the fight and his urine was a dark colour, both of which are symptoms of rhabdomyolysis.
‘Jake, because he works so hard, he put those things down to him training so much.
‘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.’