Jillian Michaels didn't just SUCK ASS at the Malibu Triathlon -- she was an EMBARRASSMENT -- so says her former "Biggest Loser" co-star Cara Castronuova.
As we previously reported, Michaels was a disaster at last weekend's big race -- admitting to TMZ she got beat by a bunch of people a world class fitness professional shouldn't have lost to ... including an 80-year-old.
But when we ran into Cara last night in L.A., the former B.L. trainer didn't pull punches -- telling us. "I would probably kill myself if that happened to me."
Cara said Michaels likely bombed because she didn't take the event seriously -- "That's what happens a lot with people that think they're in really good shape. They take things lightly and then they embarrass themselves."
'Biggest Loser' Trainer
Slams Jillian Michaels
She Embarrassed Herself at Malibu Triathlon
9/12/2013 7:51 AM PDT BY TMZ STAFF
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