Charities missed an opportunity to recruit lifelong supporters at the London Marathon, according to research.
A face-to-face survey of 300 runners at this year's event showed more than a third were no more likely than before to raise funds for their chosen charities again.
One in 10 said they were less likely to, and 60 per cent claimed they had not been contacted by their charity about fundraising initiatives other than the marathon.
"Many charities treat their runners as one-off interactions," said Niroo Rad, chief executive of Advanced Solutions International, which carried out the research. "They need to build long-term relationships with runners."
Runner Paula Weddell, who raised £2,300 for Get Kids Going!, a charity that provides sports wheelchairs for children, claimed the charity was unsupportive during her training.
"It didn't communicate well," she said. "People there seemed focused on how much money I had raised, not on me personally."
Jane Emerson, chief executive of Get Kids Going!, disputed this. "We offer a 24-hour training email hotline, a full-day training workshop in London and a family room at the finish line," she said. "And we thank all our runners by email and letter."
Julia Day, who raised £3,600 for single parents' charity Gingerbread, argued that many runners fail to engage with their charities because their main objective is securing a place in the race.
"Gingerbread was very supportive of me," she said.