Lavin, an X Games star who hosted MTV's Real World Road Rules Challenge for 10 seasons, was attempting a "nac nac" jump combination and couldn't return his feet to the pedals before landing, ESPN reports.
The 33-year-old was competing in the Dew Tour Championships in Las Vegas, Nev., when the accident happened. He suffered a shattered right wrist and broken ribs and was knocked unconscious, it was reported.
In a statement to PEOPLE, a rep for MTV says, "Our thoughts are with TJ. He is an important part of MTV's extended family and we're all praying for him."