For those who live fairly close to the city, weekend runs in the Phoenix Park, whether organised or not, are a central part of preparing for a marathon.
Clearly, however, neither the time nor the location is going to suit everyone. If you live in another part of the country or work at weekends but want to train with other people, then your most likely first port of call will be your local athletics club - many of which now contain groups specifically training for marathons, triathalons and the like.
Traditionally, many clubs would have been viewed as forbidden territory for what might be regarded as "recreational runners", but Brendan Hackett, chief executive of the Athletic Association of Ireland, believes that has changed in recent years. Indeed, the organisation is in the latter stages of compiling a list of contacts at clubs which should be up on its website (www.athleticsireland.ie) this week.
"We're certainly encouraging clubs to cater for this type of athlete," says Hackett, "and increasingly the clubs are seeing the value of appealing to them. For the runners, the clubs present a way of meeting up with like-minded people who are striving to achieve the same goals. For the clubs, people in training for marathons are an important source of new members. If they're running that sort of distance then they're clearly taking it fairly seriously and many of them can go on to contribute a great deal in other ways."
Personal trainers are an option for those looking for practical and motivational support. Many of those employed in gyms can provide a great deal of help. If you're already a member, a rather modest additional fee can get you advice or a training programme drawn up. Another option is to use an internet search engine to find somebody in your area.
Mary Jennings set up Revive Fitness (revivefitness.ie) last year just two years after being persuaded by a friend to take a short run to relieve stress. The run, she recalls, was "knackering" but it changed her life for the better and she firmly believes that, with the right support, others can reap the benefits too.
"An important part of what I do is to help people believe in it themselves," she says. "I provide a training plan, newsletter, texts, post-race social and the like but for a lot of people the most important thing is the knowledge that there's somebody there who is going to provide either support or a bit of badgering in order to help them get through the training." She is now targeting the half-marathon in September with a 12-week programme costing €140.
The first of the summer's Adidas-sponsored Race Series takes place in the Phoenix Park this weekend. The five-mile Irish Runner Challenge starts at 10pm. For details visit www.dublincitymarathon.ie