Thanks for attending our talk yesterday. I’m glad you found it helpful.
Lots of studies have been done to determine the factors that correlate best with running performance. They are in order of importance:
Speed at the anaerobic/lactate threshold tops the list with an r of around .8 next comes running economy (the energy cost) at that speed with a similar or slightly lower correlation. A very distance third place goes to the much vaunted maxVO2 about which I have written extensively here
Speed at AnT and Running Economy are the ones on this list that the majority of runners will affect the most with their training. MaxVO2 will have required enough forethought on your part to have chosen your parents very well. Not an easy task unless you are into selective breeding like is done with racing dogs and horses.
One study that really caught my interest years ago showed that the vertical jump, standing broad jump and 40m sprint speed were the best predictors of 5km race times among a cohort of similar level runners.
From there it is easy to make the leap that leg power is an important component of stride length. Listen to the Tim Ferris podcast #238. Ryan Flahrety trained Olympic Marathon medalist Meb Keflezighi to improve his running economy through strength training.
The reason that works is that power is a measure of how much strength you can produce in how short of a time. Improve the strength and there is a good chance you can improve the power. Improve the power and there is a good chance the running stride length and economy will improve.
While flat sprints are a good way to improve leg power they also entail significant injury risk because of the high impact forces. Hill sprints allow good gains in leg power with much less risk. Strides or what we call pick ups done during a longer run are done at 80-85% max speed but still have a profound effect on improving running economy. You can read about those on p168 of our book Training for the Uphill Athlete
I hope this helps.