Reigning Boston Marathon champion Meb Keflezighi celebrates his 40th birthday in May. As he prepares to defend his title in Massachusetts on Monday, the indefatigable US distance running icon gives his seven secrets to a lengthy career.

1. Avoid concrete

Meb Keflezighi may be a road running specialist, but the Eritrean-born American likes to train infrequently on the road to avoid unnecessary pounding.

“I only run on concrete perhaps twice a week,” explains Keflezighi, who finished fourth in marathon at the London 2012 Olympics. “I prefer running on grass and dirt trails. It helps protect the legs and reduces the risk of injury.

“I’m also very sensitive about when I do my uphill and downhill runs. I try to stay on a soft surface. You have to strategise your training as well as strategising your racing.”

2. High times

In an effort to match the altitude dwelling East African distance runners, Keflezighi bought a house at the near 8000ft high Mammoth Lakes in California in 2002 and lived there for the next 11 years. He has since returned to sea level to live in San Diego, but makes regular altitude training trips.

“I really feel living at altitude has extended my career,” says the 2004 Olympic marathon silver medallist. “At sea level you have to hammer out at every training session. You cannot do that at altitude, so it allows for longevity.”

Meb Keflezighi ()

By winning silver at Athens 2004, Keflezighi became the first American man to win an Olympic marathon medal in 28 years

3. Coaching faith

For the past 20 years, Keflezighi has worked with the same coach, Bob Larsen, who he believes has been central to helping him have a career that has spanned more than a quarter of a century.

“He’s been a big part of my career, a great mentor,” Keflezighi says. “Importantly he has given me the freedom to do what I’ve wanted to do. My development wasn’t rushed even when I got lapped on the track at the world championships [he has competed in the world champs over 10,000m on three occasions, finishing 23rd in 2001, 16th in 2003 and DNF in 2005].”

4. Eat sensibly

Keflezighi has been meticulous about his nutritional intake for many years, and believes his diet has been the cornerstone of his amazingly long career. However, this was not always the case.

“I got a big wake-up call in 1996,” explains Keflezighi, the 2009 New York Marathon champion. “At the time I was at UCLA, and when I was asked to write down everything I ate in the day it came to 5000 calories.

“I was told it was lucky I was exercising otherwise I would be obese. I used to eat large amounts of food and for breakfast alone I would have French toast, a pancake, yoghurt, banana and oatmeal every day.”

Since then, the 5ft 5in tall athlete has reduced his weight from 136lb to a race weight of 122-124lbs – a factor that has contributed to him avoiding injury and extending his career.”

5. Family ties

Keflezighi’s parents, his siblings and his wife have offered rock-solid support, giving his career a robust foundation.

“[Elite level] athletics is not something I can go back to in ten years time. It is a once in a lifetime opportunity,” he explains.

“I recall my parent’s driving from San Diego to Sacramento [a 1,000-mile round trip] in 2000 to watch me compete at US Olympic Trials. My brother Hawi has worked with me [as manager] for ten years and that says a lot about my family.

“We as siblings have always had the freedom to pursue our passion and be a positive contributor to society.”

Meb Keflezighi ()

Keflezighi won the New York marathon in 2009 in a then PB 2:09:15. He shaved that down to 2:09:08 at the US Olympic trials in 2012.

6. Sheer love

Without a long-standing passion for the sport, Keflezighi would simply not still be competing at a top-class level.

“I still really enjoy the sport as much today as ever – except when I’m injured!” he says.

7. Don’t push it

Never one for huge mileage, Keflezighi averages 115 miles per week. In September 2013 he also changed his training cycle from seven to nine days to aid recovery.

“Sunday used to be my long run every week, but now I don’t follow a routine for intervals, tempo or long runs,” he explains.

“I do more what my body needs me to do. My recovery sessions – whether that is massage therapy or visits to the chiropractor – are also non-stop, but better to have too much than too little.”

Meb Keflezighi’s new book Meb for Mortals: How to Run, Eat and Think Like a Champion Marathoner is out now.