An ultra marathon is any race longer than the standard marathon distance of 42.195 kilometres. Common ultra distances include 50K, 50 miles, 100K, and 100 miles, and they're often run on trails rather than roads.
Any race longer than the standard marathon distance of 42.195 km qualifies as an ultra. Popular formats include 50K, 100K, and 100 miles.
It depends heavily on distance and terrain. A 50K might take 5 to 8 hours, while a 100-mile trail race can take 24 to 30 hours or more, often run through the night.
Most are run on trails or mixed terrain, though road and track ultras do exist. Trail ultras usually involve significant elevation gain as well as distance.
Yes, most set cutoffs at individual aid stations or checkpoints in addition to an overall finish cutoff. Missing a checkpoint cutoff usually means you're pulled from the course.
You build on a marathon-level base with longer back-to-back long runs and extended time on feet rather than chasing pace. Practicing fuelling, hydration, and a run-walk strategy matters as much as raw mileage.