While the Christmas shopping season doesn’t start until late November, some local businesses are seeing a spike in business in the run-up to another big day: that of the ING New York City Marathon. In addition to this Sunday’s marathon — expected to draw 37,000 participants and 500,000 spectators — the 2008 Olympic team trials marathon is being held Saturday.

As runners prepare for these races, spas and gyms around the city have been teeming.

“There’s been a spike, definitely, in traffic,” the owner of Steel Gym, Ken Hunt, said.

Since July, his Chelsea fitness club has sold several hundred more daily and weekend passes than usual as out-of-town marathoners head to the city to train. Business is so good, in fact, that Steel Gym next year plans to offer running classes and strength-training programs to capitalize on the pre-marathon season.

An independent club on the Upper East Side, Edge Gym, learned last year that it should prepare for the marathon, the gym’s co-owner, Denis Barry, said. He said he didn’t have any marketing plans for last year’s race, but nevertheless sold more than a half dozen memberships in connection with the event. The gym saw a rush of walk-in traffic last year when gym staff ran outside to pass refreshments to some runners passing on nearby First Avenue. The drinks piqued the interest of spectators, Mr. Barry said. Edge Gym is aiming to get an even greater bump in membership this year by setting up a kiosk to hand out free smoothies and advertising material.

“It’s huge. We get this opportunity of having all this walk-by traffic,” Mr. Barry said. “You can’t pay for that.”

Edge Gym, which specializes in working with amateur and professional athletes, has also tried to sign up more marathoners this year. Runners make great clients because they typically require one-on-one training. Edge Gym had two members in last year’s race, and it expects to have 14 this year.

A publicist from Manhattan, Amy Antos, is one of them. She is running in her third marathon and has been training with an Edge Gym co-owner, Sean Kelleher, to shave some minutes off her last time of 4 hours, 30 minutes.

“Strength training really is important for running,” Ms. Antos said. “It helps your endurance.” The marathon has also been a boon for the founder and head coach of the Running Center LLC on Central Park West, Mindy Solkin. Her gym and running clinic saw enrollment rise by 20% this year for its 16-week marathon training program, Ms. Solkin said.

Exhale spa on Central Park South has enjoyed a similar rise in business, according to owner Fred DeVito. Clientele has surged 25% since August, as the spa benefits from its proximity to Central Park, where running clubs gather to train, Mr. DeVito said. The spa’s massages, which increase flexibility and reduce muscle stress, have been particularly popular with marathoners, he said.

“Marathon runners are usually doing really aggressive training. Sometimes stretching isn’t enough,” Mr. DeVito said. “We have a lot of runners and athletes practice with us. Every year we seem to get more and more.”