I was chatting with a few running friends on another venue a couple of days ago. While discussing the book by Pete Pfitzinger and Steve Douglas, "Advanced Marathoning", one of them said, "...it does not get hung up on speedwork paces, which, contrary to what I used to believe, are not particularly important (IMHO) for marathon training. Either you're doing recovery, steady, MP, LT (the only important speed pace), or below LT (hard)." Interesting thought. I thought I would expand on it and offer a few comments, some of which are likely to be controversial. But, that's OK. Controversy is a catalyst for discussion and sharing of thoughts and opinions which, in turn, leads to learning for all of us.

Firstly, I agree wholeheartedly with the comment that LT pace is "the only important speed pace" in marathon training. Not that some work shouldn't be done at a faster pace. There should be some. But, the specific pace isn't all that important as long as it's a hard effort. Why? Two reasons.

AT/LT training is the most important form of speedwork for a marathoner. I believe that AT/LT training should comprise about 60% of the speedwork in a marathon program, with the other 40% divided between aerobic capacity intervals, repetitions, and hill repeats. Why so much emphasis on AT/LT? A marathon is run at a pace a little slower (20-30 sec/mile) than AT/LT. Improving AT/LT leads directly to an increase in the pace than can be sustained for 26.2 miles. Thus, the importance of maximizing one's AT/LT cannot be over emphasized. That makes AT/LT pace important in order to realize maximum benefit from a tempo run or cruise interval session.

However, AT/LT is developed as a percentage of aerobic capacity. If aerobic capacity isn't maximized, then AT/LT development is limited. Therefore, isn't aerobic capacity development for which the faster, shorter intervals are intended equally important. Well, no. Why? That leads me into the second reason for AT/LT pace being the only important one in a marathon program.

Although there are exceptions, it isn't necessary for the typical marathoner to spend a lot of time and effort working on the development of aerobic capacity because it is usually already maxed and just has to be maintained during marathon training. Thus, the primary focus of marathon training should be to increase AT/LT as a percentage of aerobic capacity and to improve running economy. This relates to the long term development of a runner for up to 10 years after starting to train seriously. There are three elements of long distance running performance that have to be developed....aerobic capacity (VO2max), AT/LT and running economy. (Running economy is the efficiency at which the body utilizes oxygen while running a certain pace, or the percent of aerobic capacity required to run at a given pace.) These three elements develop at different rates. An exercise physiologist, Stephen Seiler PhD, does a good job of discussing this subject on a website (See http://home.hia.no/~stephens/timecors.htm Some of the other good stuff he has on his website is also interesting.) As Dr. Seiler points out, aerobic capacity develops fully after a year or less of consistent training. After that, it won't get any better no matter how many 800 intervals you run or at what pace you run them. However, aerobic capacity can vary, such as with training cycles. In other words, use it or lose it. Therefore, a level of maintenance work is necessary to maintain peak VO2max. But, maintenance takes a lot less than getting there in the first place.

OTOH, AT/LT development continues for up to 4 years. After that, continued running economy improvement accounts for almost all additional gains. And the gains do get incrementally smaller. Of course, tempo runs and/or cruise intervals are used to develop AT/LT. Running economy is improved in training through high mileage, repetitions (short intervals run faster than 5k race pace), hill repeats, and weight training. I think that the biggest benefit of multiple 20+ mile LSD's is to improve running economy. One 20-24 miler 2-3 weeks before a marathon demonstrates the necessary endurance. But, more of them offer greater opportunity for the body to learn to run more economically when tired. Running economy is of great importance to a marathoner. The less economical a runner is, the more nutrients s/he will consume during a race and the greater likelihood of hitting the wall.

Runners entering a marathon training program with little or no background in speed training and/or racing can benefit significantly from aerobic capacity intervals. However, most runners who go into a marathon training program, including many first time marathoners, have been running and training seriously for at least a year or more. Their aerobic capacities should be pretty much developed. Although some VO2max intervals should be included in their training programs to peak and maintain aerobic capacity, it should be secondary to AT/LT and running economy training. In many cases, simply scheduling a 5-10k race every 3 weeks or so during a marathon training cycle, plus a set of Yasso's near race date, will suffice.

Bottom line....the bread and butter of speedwork for most marathoners should be AT/LT training and hill repeats, with VO2max intervals playing a supporting role.