The basics of the Yasso 800’s:
The Yasso 800’s is used as a marathon predictor workout, about 3-4 weeks before your goal marathon.
You run 10 reps of 800 meters all as close to the same pace as possible. The average pace of the reps should correspond with your potential marathon time.
For example, if you can consistently run the 800 meter reps in 4:05, that indicates you can run the marathon in about 4 hours 5 minutes max.
Some experienced marathoners find this estimate is fast by a few minutes, which is why I refer to the estimate as a max.
The standard caveat regarding runner ability:
A lot of what I’m about to say below assumes you’re not a hardcore runner logging elite-like volume (70+ miles per week).
When you’re pumping out 70+ miles a week, you probably already run high-volume speed workouts like this on a regular basis, and can probably run the Yasso’s at a strong pace, such as your 5K pace or better.
For experienced runners relatively new to the marathon:
The more volume you run per week, and/or the fewer marathons you’ve done, the more you should scale back the Yasso projection.
e.g. if you run 100 miles a week and can run 800’s in 3:05, maybe estimate something closer to 3:20 for your marathon. Or if your 20 mile long run is the first time you’ve ever run 20+ miles, scale those 4:15 Yassos back to a 4:30 projection.
You should already be running a lot of miles.
If you’re training for marathon, you should be logging more than 20-30 miles a week during training. Probably way more.
40-50 miles is probably the minimum during marathon training that will produce a good marathon effort, assuming you don’t already do several marathons a year.
Personally, I feel a lot of self doubt having run 30-50 miles per week, even though many would say I’m in pretty good shape to run my next marathon (while many experienced runners would say I’m not even close).
Speedwork is not a race. Don’t run the reps like a race.
As with any interval workout, you should not race these reps: Don’t do them hard. Don’t pick up the pace and “kick” at the end of the rep.
Run every rep with a steady effort wire to wire, where once you finish you could run another few miles at that exact pace if you had to.
The reps in the Yasso workout are supposed to be a barometer of your capabilities. Running closer to your max effort will not give an accurate picture of those capabilities.
These Yasso paces should be easier than running a 5K
According to most reliable pace charts (Daniels, McMillan, etc)… you should be able to hit a desired Yasso goal at about your 10K pace or slower.
If you give more like an 8K or 5K effort to hit your pace on these reps, not only may the workout be inaccurate, but (unless you run 100+ miles a week and do workouts like this all the time) you probably won’t maintain the stamina to nail that Yasso 800 pace consistently for all 10 reps.
How easy is your active recovery period between reps? That matters.
If your inter-rep recovery is a jog instead of a full rest, the following is a good barometer of whether or not you’re going too hard: If you need to walk or stop, you went too fast.
If your version of the workout allows a full stop to rest, then a good barometer of whether you went out too hard: You cross the line not feeling like you could have kept going another 800+ meters at your pace.
Again, you never want to race to the finish of these reps, reaching the line needing to stop for a total rest. Run wire to wire at a pace you’d expect to maintain in a race, meaning you should cross the line able to keep running at that pace if you had to.
If at first you can jog your recoveries… but then you need to walk or stop at later recovery intervals, it’s not only possible your intervals are too fast… but also possible that your recovery jog was too fast.
Many runners mistakenly pace their recovery jogs at more of a normal running pace. This is too fast. These recovery jogs should be super easy and casual. Imagine you’re working yourself back from a leg injury and you’re doing a test run just to get back in the swing of things. That’s the pace and effort you should put into recovery jogs.
Another analogy I find accurate is to observe a baseball hitter’s home run trot: That’s the effort you want to be putting into a recovery jog.
The key reps are the reps BEFORE the last one.
Pay close attention to the results of reps 7, 8 and 9. In fact, you could average just those three reps and may get a more accurate Yasso 800 estimate than estimating the average of all your reps.
It’s your performance while tired in the later reps that paints the most accurate picture of your capability. Bear in mind the tendency many runners have to do the final rep hard in an effort to finish the workout strong. Rep 10 will probably look stronger than the other later reps.
Pay closer attention to how reps 7, 8 and 9 look, where you’re tired but not emptying the tank with a final flourish because you know you still have more reps to do.
Another effective estimate: Take the average of your 5 slowest reps.
Few can fake 6-10 good, accurate reps.
If the pace of your individual reps varies substantially:
(let’s say by more than 15 seconds between your fastest and slowest rep):
1. Most likely, you went out too hard. For most runners their reps in a speed workout typically vary like this: The first reps are very fast, then later reps are much slower.
2. In some cases you may start your reps super easy, realize you have more in the tank than expected, then pick up the pace in later reps (like a negative split in a race). Along with being a psychological tendency among runners… this can indicate you didn’t warm up effectively beforehand.
3. If your rep times consistently bounce back and forth by 12+ seconds per rep, you are either trying (at least on some reps) to hit a pace you’re not totally capable of running in a race… or you’re not taking full rest periods. If you’re in the middle of a Yasso workout and you see your times bouncing around, focus going forward on running a comfortably brisk pace that’s a tick slower than you want to run (whatever that means to you), and try to hit the same pace on the remaining reps.