Dan Pfaff is best known in the coaching world as the man behind Donovan Bailey, the Canadian who blitzed to Olympic 100m gold in world record time in Atlanta in 1996. He also had a brief spell guiding Marion Jones and Tim Montgomery that ended acrimoniously before the golden couple became embroiled in the Balco drugs scandal.
Now a performance director for UK Athletics at the Lee Valley Centre in north London, the American guru of the sprint game has been credited with a marathon success. This time last year Mara Yamauchi's career as a world-class exponent of the 26.2- mile event was in a hamstrung state. The world's second-fastest women's marathon runner in 2009, and second to world record holder Paula Radcliffe on the British all-time list, the Oxford native was unable to train or race because of a chronic hamstring problem.
"I was doing conventional physiotherapy rehab but it wasn't working," Yamauchi recalls. "I thought, 'I've got to try something else,' so I started working on biomechanics with Dan and he spotted various things that weren't firing and were leaving my hamstrings totally overloaded. He and the two guys who work with him, Andy and Gerry, helped me to fix the problem and in November I managed an Olympic qualifying time. I'm really indebted to them.
"Dan coaches everything, not just sprints. He's coached marathon runners before, and high jumpers and pole vaulters [Pfaff's current training group includes the javelin thrower Goldie Sayers, long jumper Greg Rutherford and 400m hurdler Rhys Williams].
"His approach is more to look an athlete, and if their body isn't functioning as it should be then tweak things."
Her Olympic selection having been secured by her third-placed finish in the Yokohama Marathon in November, Yamauchi and her Japanese husband, coach and training partner, Shige Yamauchi, are working towards the big race in London on 5 August. Mara lines up in the Bupa Great Manchester 10km road race this morning and is also scheduled to run in the Bupa London 10km event a week today.
"We're not expecting fireworks this weekend but my fitness is okay," she said. "We've just been altitude training in California, to a place called Mammoth Lakes."
Yamauchi, 38, has endured frustrating injuries since she looked to be on the cusp of a global breakthrough with her 2hr 23min 12sec as runner-up to Germany's Irina Mikitenko in the 2009 London Marathon. In addition to the hamstring problem, she has suffered plantar fasciitis, a torn adductor and two separate heel bruises.
"It's probably age," she mused.