There are two schools of thought concerning tempo runs, aka extended runs done at or above your lactate threshold, the point at which your muscles produce too much lactic acid for your muscles to absorb + clear, causing your muscles to feel weary (among other tired effects).
As your fitness improves, the pace at which you hit your lactate threshold should get faster. This can allow you to run farther at faster paces. For any race distance beyond a sprint this is of course very important.
The traditional school of thought is that tempo running at or above the threshold strengthens your muscles’ ability to clear excess lactic acid, and therefore your threshold will increase over time.
Another school of thought is that a lot of aerobic running at a sub-threshold pace over time will increase that threshold, plus higher intensity running at shorter bursts will improve your running economy and in turn that threshold.
Who’s right? To some extent both camps are right. The question is which camp’s approach is most beneficial.
You can tell which gurus and coaches are in which camp by how much tempo-and-higher intensity running they ask of you. (Advance warning: I am about to highly simplify and generalize some coaching philosophies.)
Matt Fitzgerald and Hal Higdon are popular examples of people in the high-low-instead-of-tempo camp. Fitzgerald is of course a proponent of 80/20 running, the idea that you only run hard in about 20% of your training, and the rest should be easy. Higdon of course has long been famous for his traditional, easier going approach that features a lot of long, easy running combined with days off, and typically asks for harder running in smaller, controlled bursts. Even the tempo runs in most of his plans only call for a brief foray into tempo during what’s basically a typical moderate aerobic run. The only extended tempo running he ever recommends is at marathon pace, which is a couple magnitudes below threshold.
Conversely, Jack Daniels, Joe Friel and Jeff Gaudette are prime examples of the tempo-running camp. Daniels’ plans feature a lot of higher tempo running, including many extended segments at threshold pace. Gaudette’s oft-customized Runners Connect plans are heavy on various tempo runs, built on the belief that running at pace improves the threshold. Friel asks for extended tempo runs at the threshold. To a lesser extent, The Hanson Brothers ask for extended marathon and ‘strength’ tempo runs and segments in their plans, though they don’t quite approach the threshold.
In my experience, my best development has come from a substantial volume of easy running with around one speedwork session per week. I’ve dabbled with doing more, and of course with not doing any at all. Rarely have I run a workout at anything faster than half marathon pace for longer than a few minutes at a time. In my harder non-race runs, I’ve sometimes felt good but usually more beat up than any benefit, in the short or long run.
Pretty much all my growth has come during periods where I just ran easy as much as possible, with some work on speed or running economy every week or two.
That’s one view, and obviously I’m no elite so the mileage may vary on the value of my take. But I will note that Fitzgerald’s 2017 foray into elite-level training resulted in injury (which he thankfully worked through), and most elite runners regularly get injured. And most elite coaches swear by tempo runs as well as absurdly high training volumes built largely around moderate to hard running.
I realize I’m getting a bit away from the point. Does this lend merit to Jonathan Savage’s contention that tempo runs are not the best way to go?
A lot of other hard-easy-no-tempo running minds argue that that there’s a zone between a moderate aerobic effort and the nether regions of the lactate threshold that isn’t beneficial for runners to train in, that you won’t see a worthwhile positive benefit running in that zone. Phil Maffetone’s MAF Method (which is an extreme deviant of both approaches by recommending you virtually never run above a moderate aerobic pace) provides a good baseline for where that moderate range begins.
This indicates that tempo-running might not be good, not just for lactate clearance reasons, but because it’s in a low return on investment aerobic zone in general. Running at the threshold isn’t good by that mindset, but then again neither is running at any nearby range below it.
Again, the argument is not that tempo runs are bad. All can agree they provide some training benefit. The argument is that doing them is not as beneficial as sticking to a polarized mix: Lots of easy runs, mixed with brief bouts (reps, segments within longer runs) of tempo or harder running.
I think the best bet in most cases is either longer tempo-cruise intervals like 1-2 miles (whether as their own workout, or mixed into a longer run), or to tack a 2-4 mile tempo session at the end of a long run (a fast finish or 3/1 long run)
Is that good enough for a marathon, where the goal is to run at tempo for the entire race? The main criticism of the long run is that most do it too slow, when the goal in a race is to do it at a faster pace. The fast finish long run is in part intended to address running at pace while tired, but most won’t run 3/4 of the marathon at a slog and then fire it up for the last 10K.
I think Daniels gets it kind of right with his 2Q Plan‘s mixed tempo long runs, albeit he asks way too much for most runners (and probably even for elite and front-pack runners, though they have the fitness to survive it).
I think something similar to a fartlek (and, to the credit of the Canadian Running Clinic training plan, they ask this as a workout) would work better, where the long run has faster segments interspersed throughout. In fact, you could do far worse than just doing long runs with some minute on, minute off fartlek segments in the middle and end.
You are welcome to toss these ideas around and see what you can come up with.