When Todd Crandell competes in the Ironman World Championship in Hawaii this month, it will mark his 12th Ironman in seven years. The remarkable is no longer remarkable, of course. Tens of thousands of people have completed one.

But Mr. Crandell's path to the starting line was unconventional. He first learned of the endurance showcase while smoking crack cocaine.

Now sober, Mr. Crandell, 39, recalls how at 21 he watched television coverage of the triathlon (2.4-mile swim, 112-mile bicycle ride and 26.2-mile run) in awe while struggling with alcohol and cocaine addictions. In a memoir, Racing For Recovery: From Addict to Ironman, he describes his path of self-destruction as marked by drug dealing, arrests and living out of a Buick filled with gin and Motley Crue posters.

Today he runs Racing for Recovery, a five-year-old foundation based in Sylvania, Ohio, that encourages people battling dependency to exercise as a way to create much-needed structure in their lives. More than 2,000 people have run in 5-kilometer races organized by the foundation around the country.

Strenuous exercise has not been a part of traditional recovery programs like Alcoholics Anonymous or the Betty Ford Center, which emphasize abstinence above all else. But a few treatment centers, and former addicts like Mr. Crandell, are coming to see the value of road running and other fitness regimens in building confidence and managing stress for those battling alcohol and drugs.

Mr. Crandell said he and other addicts he knows embrace regular conditioning as a way to help them stay sober and to pursue goals. And for those who are competitive, preparing for a race not only eats up time and distracts them from temptations, it also can help them establish goals and make clean-living new friends.

Odyssey House, a treatment program in New York City, shares that view. On Sept. 23, 1,000 walkers and runners, many of them ex-addicts, participated in a 5-kilometer race organized by the program. It also now has 15 residents preparing for next month's New York City Marathon.

"We're turning people who were heroin addicts, cocaine addicts, crack addicts into marathon runners," said Peter Provet, the president of Odyssey House. "I really believe it's a model for other treatment centers."

A new study seems to back up the idea that exercise can play a role in addiction recovery. Butler Hospital, affiliated with Brown University in Providence, R.I., recently completed a study that tracked 44 alcoholics and found that outpatient treatment and 12 weeks of aerobic conditioning increased the likelihood of their remaining sober.

Research also has found that aerobic exercise improves symptoms of mild to moderate depression. Considering that depression is a risk factor for relapse for substance abusers, alleviating some of the disease's burden may help addicts stay sober.

Dr. Provet, a clinical psychologist, calls physical activity "the perfect antidote to addiction." Ordinary hobbies don't suffice, he said. "Knitting is good, but knitting does not address the negative breakdown of the human spirit and human body. Running does."

Odyssey House, with over 1,000 low-income patients in its nine centers, encourages clients to run. Activity counselors lead residents on group treks three to four times a week; athletic clothing and footwear are provided when needed.

Nancy Waite-O'Brien, the vice president for clinical services at the Betty Ford Center in Rancho Mirage, Calif., said she thinks that helping addicts train for a race is a "terrific idea."

But helping patients accomplish their training goals is not always feasible for short-stay centers like Betty Ford, she said. Patients tend to stay three to four weeks at the Betty Ford Center compared with state-financed centers like Odyssey House, where patients reside an average of nine months to a year.

The Betty Ford Center does not reject the benefits of exercise; it has a gym and offers some personal training, which the able-bodied can take advantage of, Dr. Waite-O'Brien said. But, she said: "Sometimes people are physically sick when they arrive. What we're doing is mostly helping them get moving."

The Butler Hospital study suggests that incorporating exercise into recovery programs may be beneficial. Richard A. Brown, Butler's director of addiction research, said their randomized controlled trial is in the final stages, but has already noted the impact that moderate exercise has had on previously sedentary alcoholics in outpatient treatment.

The study used a control group, which was given only brief advice on the benefits of activity. The intervention group, though, received a weekly gym session, with instruction, on cardiovascular machines. The exercise group also attended discussions about overcoming barriers to activity, and were instructed to do two or three workouts on their own.

Two months into the intervention, the group that participated in structured exercise sessions was two and a half times more likely to be abstinent from alcohol than those in the control group, according to preliminary results. Dr. Brown also reported that the more moderate exercise the alcoholics did, the higher the rates of their abstinence.

"What we showed was when people are actively engaged in exercise they are doing better," Dr. Brown said. "The question is how to keep them engaged." After six months, Dr. Brown found, his charges ran into the same problem many of us do: their training dwindled.

Jean Ferlesch, 54, who has been sober for two decades, wouldn't dream of giving up her running and weight lifting routine. She recalls how the toil of exercise helped her manage emotions wrought by her divorce that at one time would have caused her to drink. "I started going to the gym and I was so sad and so angry," she said. As she built up endurance, she imagined herself emotionally strong. "I ran through my pain."

Being able to persevere was novel, said Ms. Ferlesch, a store designer living in Brooklyn. "Years ago when something hurt, I would do anything to get away from that feeling," she said. "It's a more sophisticated understanding of pain now. I can sit with it and go through it, be it physical or emotional."