Training Volume Is It THAT Simple?

Is it as simple as time training = better performance.  if you're a part time runner, you'll just have to live with part time performance?  

Big races coming in this area and it's got me 'athinking.  'Training volume' is it an aggregate indicator of how you finish in a race?  Picture this: The army 10-mile'r about 20-25,000 finishers.  Imagine the finish in a single file line.  Could you take a picture of them in single file and draw a circle around each group of 100 runners and write the average training miles (or weekly time invested) next to each group and see a definite trend of training volume to finishing times?  Is it as simple as finishers 1-101 trained 'xxhours/week, the next hundred averaged xx-1 hours/week, and so on?  Maybe the 10-miler is too short to see a definite trend, how about a big city marathon, or an ultra (like Comrades)?

This is easily true at the extremes.  Those that plan to walk these races probably have zero to 'a couple miles' a week under their belts - and those finishing at the top logged up to 100s of miles a week.  I'm generalizing here, many athletes have differing histories of volume, better/worse genetics, etc etc.  but could logging miles be the 'key' in endurance sports?  

I found this helpful study on finishers of the Comrades Ultra (Link Here).  Form the piece:

Those with the fastest times (6 to 6.5 hrs) had done 2574km (1600miles) and the 10 to 11 hrs finishers 1030km (640mi) <<miles done in the 6mos leading up to the race>>. The current elite runners claim to run in excess of 3000 to 3500 km (1864-2174mi) in preparation for the marathon, which is similar to what runners were doing twenty years ago.

 …<also note>Despite their high training load the male silver medallists were the least likely to have spent a week off due to injury and illness (28.6%) - but then the corollary is that this would have allowed them to complete a higher total mileage.  The majority of the men who finished in over 10 and over 11 hours (76% and 58% respectively) had been unable to train due to injury or illness.  Likewise, the women who finished in under 9 hrs had the least compromised training (15.1% were unable to train for a week or more) while up to 50% of the women in all the other medal groups had been affected.  Six of the seven women who did not finish had been ill and/or injured and their total training mileage was lower than any other group in the study.

In table form, years of experience running, and training volume in the 6mos leading up until the race.

Training volume equals performance and training volume equals less injury rates.  If you're competitive, it is your job to accept how much time you have to train and that is most likely to determine how you race (or be injured ...more on this later!).