Last fall I started upper body weight training with free weights. I didn't want to get old with strong leg muscles and atrophied upper body muscles. I was surprised that this seemed to also benefit my running efficiency. I felt stronger, and with more endurance, not sure about speed. I didn't really expect anything you did with the upper body would have much of an effect on running, but anecdotally, at least in my case, it seems to be a benefit.

I did some half-hearted Googling around on this topic, and found all sorts of "studies have shown" articles claiming weight training does indeed help runners, but couldn't find the studies, nor could I find anything directly relating to upper body only training, tho all the programs I found had the full complement of leg and upper body work. I did notice marathoners claiming upper body work led to improved ability to finish the race strong.

These claims, anyway, caught my eye --

Scientists in Finland found that strength training could boost maximal running speed by 10%. Strong and evenly balanced muscles help posture, which contribute to good running form. Research has linked strength training to a lower risk of injury and a 4% improvement in 5k race times. [http://www.coolrunning.com/major/97/training/auc0820.htm]

In addition to injury prevention, weight training improves performance. Studies show that with as little as ten weeks of weight training, 10K times decrease by an average of a little over one minute. The research has also shown that running economy defined as the steady-state oxygen consumption for a standardized running speed (milliliters per kilogram body weight per minute), will be improved due to weight training. By improving running economy, a runner should be able to run faster over the same distance due to a decrease in oxygen consumption. Improved running economy would also increase a runner’s time to exhaustion. [http://www.fitnesssports.com/Strengthtraing.html]

I imaging elite runners know about this and have coaches suggesting what they should do (tho I did not get a sense from my brief search as to what percentage of elite runners seem to think weight training is a good idea or bad idea), but I'm pretty clueless about running physiology and training, etc. I do know that it seems to help me, anyway. It is one of those things I sort of stumbled into for the wrong reason that seems to help. This is an obvious glaring weakness in the US O program -- the lack of an army of coaches just telling us these things; what works, what doesn't.

There are probably all sorts of things out there that can help one improve, just waiting to be discovered. Ironically, I got into O because I'm a recreational treasure hunter, and it was described (incorrectly) as such, then I ended up falling into the more serious side of it, but it seems the treasure hunting turns out to be digging up different ideas for improvement.