Sport - 8 free documentaries about olympics, running & athletics.
Start with I Trained with Kenya's ELITE Runners (35 min, National Geographic), then The Mirage: Timothy Olson's Race Against Time (60 min, National Geographic). All 8 documentaries here are free to watch from their makers' official uploads. To read deeper, the top-rated book on olympics, running & athletics is Born to Run by Christopher McDougall.