I don't know, but my guess would be "free soloing". Basically, climbing up a rock face with no safety equipment. Enthusiasts keep track of speed records for popular climbs. Records are often proven with personal gopro footage, eye witness, etc.
I wonder what 'personal' means in his context though. A lot of the big speed runs, el cap, that face in squamish, are pretty established and not a super personal experience, like say picking your favorite one pitch and doing it.
But I am shocked at how many climbers I know who free solo more than 40 feet off the deck...
https://en.wikipedia.org/wiki/Speed_climbing#Free_soloing