CHICAGO — If a popular marathon is sold-out, procrastinators can still finagle their way into the race. And no, we don’t mean sneaking onto the course.

The secret is joining one of the dozens of charity groups that still have some coveted late-entry forms. Simply commit to their cause — raise some money — and you’ll be at the starting line with 45,000 other runners, hobby joggers and walkers, regardless of your experience or ability.

But while marathons can be rewarding and life-changing, they can also be grueling, unpleasant events, especially if you’re new to the sport. If you’re also fundraising — no easy feat — you might feel pressured to keep pushing with training when you shouldn’t. And some running coaches worry that the charities are more interested in raising money than in the health of the runners, a charge the charities deny.

“Most people don’t understand how hard it is to run 26.2 miles,” said DePaul head track and cross-country coach Patrick Savage.

The mushrooming success of charity running is helping drive a marathoning boom.

Once hard-core competitions that excluded women, marathons are now an all-comers party; some even resemble parades.

Last year, more than 7,300 charity runners raised more than $9 million at the Chicago marathon. This year’s race includes a record 112 registered charities, fielding teams ranging from two to 1,200 members.

In exchange for a minimum donation of $1,400, for example, runners with the Leukemia and Lymphoma Society’s Team in Training (TNT) receive a race entry ($125 value), group runs and coaching, a 16-week structured training schedule, camaraderie and other amenities.

Many say they like the charity training programs, which now include bicycle rides and triathlons and adventure races, because giving to a worthy cause makes the events more meaningful. The programs attract people who may never have considered the event without a charity tie-in.

But marketing campaigns target anyone who might be inspired by the cause. Inadequate training programs and trying too much too soon can lead to injuries and make marathons a one-off experience, rather than serving as an introduction to a lifelong activity, said Chicago running coach Bill Leach, director of gait analysis and speed training for the Chicago Area Runners Association.

“Running a marathon has been romanticized without a reason,” added Leach, who thinks first-time runners should try shorter races first.

When he coached charity teams, he believed in their mission but found “precious little attention was given to the best interest of the runner,” he said. “When push comes to shove it’s: ‘Now, we need the credit card information.’”

Another criticism, Savage said, is that some programs “are not really training people to run a marathon. They’re training them to ‘complete’ 26.2 miles.”

The difference often sparks a heated debate within the running community. Slower runners are often still working toward the finish after the course has closed, which can pose safety issues.

Charity officials freely acknowledge that fundraising — not training runners to break three hours — is their primary mission.

But they bristle at the charge that the training programs are lacking.

“Our goal is to do everything we can to get people to the starting line injury-free, healthy and prepared. If we’ve done our job, it’s a party on race day,” said Marie Jarrell, a physical therapist in New Lenox and TNT’s head marathon coach for Illinois. “But like anything else, runners have to take responsibility as well.”