I agree 100% with the standpoint that anaroebic exercise, is better for building speed and endurance. when I used to run a mile or a mile and a half every day a longtime ago, I was going for the endurance more so then the speed, I ran a slow steady pace and i ran my miles in somthing like 8 1/2 or 9 mins.
Now, I've been trying to run them as fast as possible. (keep in mind I had'nt ran miles for a while when i started new going for speed) My miles started back at like 8 1/2 mins r so. I'd run at an uncomfortably fast pace until that pace became comfortable and then I'd run faster. Over the past 3 or 4 months my miles have come down to an average of 6 mins and 40 seconds, and dipping lower. Endurance running at a comfortable pace for 3 or 4 months didnt give me results anywhere near as good.
While endurance running gave me pain in my knee's, anaroebic gives me shin splints. Maybe its the higher impact from running faster?