Intervals produce significantly better results than tempo runs, at least according to a study carried out by Peter Snell, former 3-time Olympic gold medalist and 800 meter world record holder.
As summarized by Owen Anderson, Snell trained 2 groups of athletes, one with tempo runs and the other with 200 and 400 meter intervals. Each group performed their prescribed workouts two times per week. After 10 weeks, the interval group improved their 800 meter times by an average of 11.2 seconds and their 10K by 2.1 minutes! The tempo trained group also improved, but only by about half as much.
One of the keys to this difference was a whopping 12% increase in VO2 max in the interval group, compared to a 4% improvement in the tempo group. According to Anderson, "The problem is that tempo training, carried out at close
to lactate-threshold velocity, by definition produces very little increase in
blood-lactate concentrations and thus does a poor job of stimulating muscle
cells to get better at clearing lactate from the blood." Read the full article found at planetultramarathon.
C) 2007 Dave Elger all rights reserved