For some of us, a half-hour’s run is just about right: the golden mean between immoveable couch potatohood and chronic tendonitis. Others, however, find satisfaction, meaning and endorphin-laced highs in covering great distances on pumping feet. Two of those extra-milers have new books out, and a third entrant, a self-described “often-injured runner,” has written with admiration about a tribe of Mexican Indians born for seven-league boots.

1. Marshall Ulrich, who will turn 60 later this year, is an ultramarathoner — or, better yet, a quintathoner, since he often runs 125-mile races, about five times the distance of an orthodox marathon. In Running on Empty: An Ultramarathoner’s Story of Love, Loss, and a Record-Setting Run Across America (Avery, $26), Ulrich notes that something in him “wants to get out there, in the middle of nowhere, and think about something” — presumably something other than pain.

2. Robin Harvie begins The Lure of Long Distances: Why We Run (PublicAffairs, $25.99) with an epigraph from an ominous source: British explorer Apsley Cherry-Garrard’s “The Worst Journey in the World.” After that, it’s all uphill, with Harvie running rings around Marshall Ulrich. In Harvie’s world, only after you’ve run 150 miles — also known as the Spartathlon, roughly the distance Pheidippides ran to see if the Spartans would help the Athenians against the Persians — are you entitled to get your running shoes bronzed.

3. Those great Mexican striders are the Tarahumara, who live high in the Sierra Madre in what Christopher McDougall refers to as “a shorebound Bermuda Triangle known for swallowing the misfits and desperadoes who stray inside.” In Born to Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen (Vintage; paperback, $15.95), McDougall tells what happened when the best U.S. marathoners were pitted against the Tarahumaras’ best and lithest.

Dennis Drabelle