Endurance Training Slows Top End Speed

From Matt Fitzgerald

The problem with this weightlifting expert’s argument is that the training required to increase your maximum sprint speed will reduce—sharply, in most cases—the percentage of maximum speed that can be sustained over long durations. So the runner who begins with a maximum speed of 18 mph and the ability to sustain 50 percent of that speed over 10K, and who then increases his or her maximum speed to 20 mph, is now able to sustain only 40 percent of his or her maximum speed over 10K and goes from a 41:20 10K runner to a 46:30 10K runner.