Why do we run? It’s the question to which there are as many answers as there are runners. The elite run to be the best; millions run to improve their times; others to be better versions of themselves. Some run to inspire others or to champion a cause; others to improve their health.

For others still, running is a way to say yes to humanity, to force social change; others to stick two fingers up to officialdom. As we saw at the Paris marathon in April, and at Boston in 2014, there are plenty who run to shout a deafening “no” to those who spread terror.

And then there are those who run to defy the elements, through scorching heat and freezing cold; they run to conquer new territories, to take mind and body to places they have never been.

Jon Sutherland has run every single day since 26 May 1969

I have looked at all these runners and more. For many, it’s the extremity which is the attraction, and among them I have numerous personal favourites. Jon Sutherland, of California, has run every single day since 26 May 1969, a running streak which, on 5 September, stood at an astonishing 17,270 days.

Fabulous, too, is the achievement of Fauja Singh. Plenty of people feel 100 years old at the end of a marathon. Singh actually was at the start of his. When he completed the Toronto Waterfront marathon in 2011, Singh became the world’s oldest marathon runner in a time of 8:25:16 – whatever Guinness World Records say. They want a birth certificate which Singh simply doesn’t have.

Wonderful, also is the achievement of Terry Fox (1958–1981), the Canadian who was just 18 years old when he was diagnosed with bone cancer and had to have his right leg amputated 6in above the knee. Overwhelmed by the suffering of his fellow cancer patients, particularly children, he became the first person to run across Canada with an artificial leg. Tragically his cancer caught up with him before he could complete the task.

My greatest favourite is Hyvon Ngetich, the 29-year-old Kenyan runner who collapsed about a quarter of a mile from the finish line in the 2015 Austin marathon. Look up what happened next on YouTube, and I defy you to watch without a little tear in your eye. Ngetich completes the course on her hands and knees. With two metres to go, she is knocked into third place.

That piece of film and the stories I’ve investigated have been in my mind as I have battered back to slightly-shaky health over the past six months. In February, I was mugged in Cape Town as I walked back from the cricket: stabbed, kicked, punched and left for dead by the roadside. I’d already completed the first draft of my book. When I came back and embarked on the long road to recovery, I suddenly saw the runners in a new light.

I ran the Berlin marathon in 2008, the race in which Haile Gebrselassie broke his own world record. He said the most gracious thing to the rest of us: “You were my tailwind and are all record-breaking runners, too!”

It was a thought I’d always cherished – and when I ran/hobbled again a month after the stabbing, I realised that the remarkable runners I was writing about were my tailwind. They helped me through, because that’s what running does. It lifts, inspires, repairs and heals. It reconnects and reconstructs and I’d recommend it to anyone who can do it. Certainly, in the midst of trauma, pain, infection, hospitalisation and surgery, running was the only thing that made me feel me again. And just thinking about it makes me want to get my running shoes on.

In The Running by Phil Hewitt is published by Summersdale, at £9.99. To order a copy for £8.19, go to bookshop.theguardian.com