Progression
See how O'Brian is progressing
Every mark O'Brian has run, plotted over time — watch times drop race by race, catch breakout performances, and compare season to season for every event.
Join MileSplit PRO Already a PRO member? Log inProgression
Every mark O'Brian has run, plotted over time — watch times drop race by race, catch breakout performances, and compare season to season for every event.
Join MileSplit PRO Already a PRO member? Log in