Ponder this:A talented sprinter turned 800m runner, her PB for 200m is just over 26 seconds.
Her PB for 800m is 2m 9s.
When in an 800m race, she has no "kick", being left behind by the winners over the last 150 or so metres of a race. Her usual finishing position is 3rd or 4th place.
Seeking a solution, her fahter and coach consulted a sprint expert so that they could learn more about speed drills and anaerobic work to improve her kick. Will this work for this talented 18 year old?
The answer is "No!" of course. Her problem is a stamina one - not a lack of speed or anaerobic capacity. In theory, she has more than enough speed to run way under 2 minutes for an 800m. Training to sprint 200m faster will do nothing to lower her 800m time. Concentrating too much on speed and anerobic training might even cause her to run slower.
Athletes like Peter Snell and John Walker were never the fastest sprinters in the fields, yet they both posessed the most stunning kicks over the last 200m of a race, be it 800m or 1500m. They had aerobic stamina, the oxygen uptakes honed from years of distance training and racing events like road and cross-country - as well as a good measure of speed training, of course. This stamina meant they were able to conserve their anaerobic reserves more than their speed-trained opponents. When it came to the winning sprint, they had more gas in reserve for firing their after-burners than anybody else. They consistently won.
Stamina is what wins races that are longer than about 4oom.