On the Edge (1986)

Looking none the worse for his age, Bruce Dern convincingly plays an amateur long-distance runner in On the Edge. Banned from American competition for violating his amateur status, Dern decides to prove he's still got what it takes. The middle-aged athlete enters the grueling Cielo Sea race, which has defeated many a man and woman half Dern's age. Our hero's obsession allows him to touch bases again with his former lover Pam Grier, his alienated father Bill Bailey, and his onetime trainer John Marley. It's Rocky for the rocking-chair set, but On the Edge is contagious in its euphoria.