I haven’t been running for the last 5 years. However, for whatever its
worth to you, I will offer my experience with Yassos in 1998 and 1999.
I spent 2-hours with Bart Yasso in the RW booth at the 1998 MCM expo and had
a chance to chat with him about Yasso 800’s. I had not used them previously and, after talking with him, decided to
give them a try for the Philly Marathon four weeks later. I had determined that I was in 3:55-4:00 marathon condition, which
I set as a goal range for Philly. I scheduled a set of Yasso’s for seven days before the marathon. Actually, I ran 10x880
yards rather than 10x800 meters. The difference is only 4.5 meters, or about four strides at my pace and stride length. I
ran them in 3:44, 4:01, 3:54, 3:59, 3:53, 3:59, 3:52, 3:59, 3:51 and 3:56 for an average of 3:55 with average recovery of
3:57. (The up and down splits were due to running them over a measured half mile on a flat section of the B&A Trail. The
slower splits were into a light breeze and the faster ones with the wind to my back.) I ran Philly a week later in 3:57:50,
just about in the middle of the range that I expected and close to the Yasso “prediction”.
In 1999, I again determined that I was in 3:55-4:00 condition and scheduled
a set of Yasso’s 18 days before Philly. This time I ran half mile intervals on a treadmill that had speed control in
tenths mph. Since the treadmill was located indoors where the temp was 70 degrees, I opted to run them at a Yasso pace of
4:00 (7.5 mph) with ¼ mile recovery jogs in 3:45 (4 mph). My race plan was based on a 3:55 marathon. However, race day turned
out to be a warm one….just standing around before the race in shorts and a singlet was comfortable and the temp reached
70 by the end of the race. On race morning, I estimated that the “warm” conditions would cost me about 10-15 minutes.
So, I revised my goal to 4:10 and adjusted my race plan accordingly. I ran 4:10:54. I did run slightly positive splits…..2:04:03
first half vs. 2:06:51 second half….which I attributed to pushing the pace just a bit in the second 6 miles. With just
a bit more conservatism in the second quarter of the race, I might have gotten under 4:10, but not much under. The race I
ran was probably within a couple of minutes or so of the best I could have run under the conditions we had. I am confident
that, if it had been 15 degrees cooler, I would have run 3:55 or faster, which would have beat my Yasso “prediction”.
You might know from previous threads that I view Yasso’s as primarily
a test of one’s VO2max readiness to run a specific marathon time. However, they reveal little or nothing about one’s
endurance base, LT or running economy, all of which affect marathon performance to a greater degree than VO2max. Using Yasso’s
alone as a marathon predictor is a mistake. It’s better to set a goal based on other criteria, such as performance in
a shorter race coupled with training mileage, then use a set of Yasso 10x800’s to “confirm” one’s
VO2max ability to support it. (See “Yasso’s – Training or Test” and “Predicting A Marathon Time”
on the Marathoning section of my Running Page.)
There was a thread in November, 2005 on this forum concerning Yassos that Bart
Yasso picked up on. In that thread, I referred to my older “Yasso’s – Training or Test” post that
is archived on my Running Page. After reading it, Bart emailed some comments to me. The following is his email:
“I saw your post and checked out your running page. Very nice. You have
lots of helpful information for runners of all abilities.
“On the Yasso 800s, you have it right. It’s a test or a barometer
as I call it. You need to do a heavy dose of long runs, hill workouts, and lactic threshold workouts to run a great marathon.
I always do mile repeats and one of my favorite workouts is 800, 1200, three repeats. I always go back to 800s to test my
“Any runner going to your website can learn a few things. Keep up the
I appreciated Bart’s comments. But, mostly I was just glad that I got
something right for a change. J