Ryan Flaherty was at Nike for awhile, not sure what he is doing now, but he hypothesized based on his work with hundreds of athletes, that really all that mattered for speed was how strong someone was relative to weight. He measured this using a scale and one rep max with the hex bar deadlift. He mainly worked with football players, but he did help train Meb in the deadlift prior to his 2014 victory at Boston.
My guess is that the vast majority of runners would see more improvement from getting lighter rather than running more miles - it is much easier to improve strength to weight ratio by decreasing weight rather than increasing strength.
Some of Flaherty's more nuanced discussion from Ferris podcast transcript: "
"Ryan Flaherty: Really simply, stride length and frequency is the product of mass-specific force.
If you help someone increase their mass-specific force, naturally, those two things are going to occur. When you’re a marathon runner, on average, it will take 20,000 strides to run a marathon. Well, if I can increase your stride length by increasing your mass-specific force and your normal running gait by three inches – big increase, three inches – on your normal running gait and your stride length, three inches times 20,000 is 60,000 inches, which is around 5,000 feet, which is close to a mile. So, you’re a mile ahead of where you were last time you ran that marathon purely by increasing your mass-specific force. It’s that simple.
Tim Ferriss: Got it. How did your training differ – if at all – for Meb versus your sprinter – “sprinters” meaning track and field, football players, fill-in-the-blank.
Ryan Flaherty: The majority of marathoners don’t have a desire to get in the weight room and strength train.
For a long time, the thought has been that it can only go to hurt you and injure you or add size, which is what most marathoners don’t want. So, the biggest thing was teaching him that by hex bar deadlift training in the concentric zone only – so, doing no eccentric loading – that he could stress his nervous system, recruit larger motor units without adding any weight. He started at 127 pounds, ended at 127 pounds, and by just introducing that one exercise – I didn’t touch his running or touch anything else that he did in the weight room; it was simply that one exercise – once a week, it improved his stride length and his running gait, which in turn helped him run faster.
Tim Ferriss: Love it. Love the simplicity of it.
Ryan Flaherty: It’s super-efficient, right?