Ryan Stevens sat on the edge of a concrete balustrade in Central Park after finishing three laps around the reservoir. She and her fellow runners [are] from Odyssey House, a drug and alcohol rehabilitation center. Ms. Stevens, who is 36 and lives in the Morris Park neighborhood of the Bronx, was prepping for Sundays New York City Marathon her fourth, she said as a member of a unique group of competitors: former drug users who turned to running as part of their recovery from opioid addiction. Ms. Stevens said she grew up in Rhode Island and became addicted to her mothers prescription opioids at 22. That opened the door to ecstasy, cocaine and crystal meth. She completed an inpatient residential program at Odyssey House in June. Running, she said, has been central to her recovery. The 45 runners on the Odyssey House team who are planning to run New Yorks 26.2-mile trek include 19 current clients. The rest are supporters and alumni. John Tavolacci, Odyssey Houses chief operating officer, said he has run 22 marathons. He started the running group in 2001 as a supplement to treatment, based on a strong belief that running can be effective in helping overcome addiction. He has watched the Odyssey House team build self-esteem among participants, create a cooperative environment, and fill time for runners that otherwise might have been spent on negative pursuits.