If this unsettling experience befalls you during April, you should know that the person inside the oncoming suit - whether it be that of a Teletubby, a Luke Skywalker or the Matterhorn - is not being silly, but sensible. Ask Neil Black, because he knows.
Black, physiotherapist to the British athletics team, is a regular contributor to pre-Marathon teach-ins for first-time charity runners. His advice for those about to travel 26 miles and 385 yards in absurd outfits is the same as for more conventional competitors - be familiar with what you run in. Does that mask suffocate you as soon as you start moving? Do those leggings chafe? These are things you need to be aware of before you embark upon your chosen course.
Advice to aspiring marathoners is available from every quarter. Whole books are devoted to it. Newspapers and magazines detail dos and don'ts. According to Black, there is simply too much information out there for the rookie runner, much of it conflicting.
Earlier this week John Spurling, a 59-year-old advertising executive who is seeking to raise pounds 1m for charity in this year's London event, had an opportunity to quiz the Olympic champion, Josiah Thugwane, on his pre- race diet.
The South African explained that he normally ate meat and maize 24 hours before starting. Spurling, whose sporting experience in the past 40 years has been confined to playing golf and taking up foolhardy bets during late-night sittings in Langan's, pondered on Thugwane's words for a second or two before translating them into more meaningful form. "So basically," he said, "That means bangers and mash." The prospect seemed to please him.
Spurling was working out for himself one of the main messages which Black attempts to put across in his seminars - that, ultimately, each runner has to discover what works for them. If it's bangers and mash, so be it.
Many different messages have been required from Black this year in order to set virgin marathoners back on the right lines. "One lady stood up during our question time and said her main worry was not whether she could complete the distance, but whether she could get lost on the course," Black recalled.
He assured her that the presence of a wide blue guideline along the whole of the route should still her fears. And, of course, the presence of 30,000 other runners all going in the same direction would also offer a strong clue.
Another of Black's charges was troubled by sore legs and persistent fatigue. He had read an article which maintained that the key to marathon preparation was two-hour runs. And so, at six o'clock every morning, he had been setting out on a two-hour run. He was advised to ease off a bit.
There was a query of a very different kind from a man who said he was losing weight during his training, even though he insisted he was eating 12,000 calories per day. It was suggested to this seeker-after-truth that if he really was losing weight on 12,000 calories per day, he should simply eat a bit more. I can't help thinking that this man should also have been encouraged to gain a worldwide patent on his dietary technique.
But perhaps the most challenging case Black has had to deal with this time around concerned the runner who presented him with a Cunning Plan. Here, in all its majestic simplicity, it is.
Run the first mile. Then sit down, keeping the legs moving in a peddling action for one minute. Run the second mile. Then sit down and keep the legs peddling for two minutes. And so on, with steadily increasing "rests", 26 times over.
Black pointed out as tactfully as he could that this approach involved a number of potentially debilitating factors, no least of which was the risk of severe abdominal strain from all the stationary exercising.
However, the Cunning Planner - who had never previously run further than four miles at one sitting, as it were - remained convinced that he had made a significant breakthrough in distance-running technique. And so keen was he to share his inspiration that he handed Black the full instructions as he was about to address a newly arrived group of charity runners.
Black put the note in his back pocket, but chose not to pass it on.Reuse content