Defying barriers is the life's blood of an athlete, whether those barriers are posed by the clock, the lay of the land, or the limitations of the athlete. Tonight's program looks at disabled athletes who through determination and courage push themselves to the extreme. Robert Charlton's exhilarating Survival Run (1980, 12 mins, 16mm) follows Harry Cordellos, a blind runner, as he traverses the rugged terrain of Mt. Tamalpais during the Dipsea race. It's all downhill in Christian Schneider's hyper The Chariot Races (1997, 27 mins, 3/4" video), the story of John Davis, pioneer of off-road wheelchair racing. Davis's athletic career-he's a Paralympic gold medalist ski racer-is due to his tenacity, but also to advances in adaptive sports equipment. The high-tech Cobra wheelchair propels Davis through some rousing off-road courses and a thrilling joyride through San Francisco. Paraplegic athlete Mark Wellman knows no limits. His derring-do, well documented in Eric Perlman's No Barriers (1994, 48 mins, 3/4" video), has taken him to the top of El Capitan and Half Dome, as well as on an arm-powered ski trip across the entire high Sierra. Up to the challenge, these disabled athletes take things to the extreme.-Steve Seid