If you like endurance and films about great endurance you'll like Unbreakable: The Western States 100. This movie documants one of the greatest and most well established running ultra -aces in America.
According to Wikipedia:
"The Western States Endurance Run, known commonly as the Western States 100, is a 100-mile long (161 km) ultramarathon that takes place on trails in California's Sierra Nevada annually, on the last weekend of June. The race starts at the base of the Squaw Valley ski resort and finishes at the Placer High School track in Auburn, California. Runners climb a cumulative total of 18000 feet (5500 m) and descend a total of 23000 feet (7000 m) on mountain trails before reaching the finish.
Check out the film's trailer below.