Lactate Tolerance and Stacker Workouts

As I mentioned in my last post, anticipatory grieving saw me doing a lot of hard intervals over the last year. This short post describes a really cool workout that I did, how I expect to change it in the coming months, and why I think it’s a pretty vital part of my future workout plans.

Quite awhile ago, I posted about lactate tolerance workouts, MCT-1, and all sorts of other complicated stuff on improving lactate processing. That post was a privilege to write because, while it took a lot of work to pull together, it encapsulated a lot of my thinking up to that time– and still does. Before reading this post, I’d suggest reviewing that other post first because I hope that this one won’t cover the same territory. Instead, I consider this post is a bit of an update based on workouts forced on me by circumstances in my life.

I mentioned in that earlier post that I was reluctant to suggest one-minute all-out sprints in running workouts particularly for older age-group athletes. I’ve changed my mind about that. First, few of us can truly run a dozen or more “all out” one-minute intervals. Instead, it’s better to think of the intensity level as “as hard as possible for repeated one-minute efforts.” While you should still be huffing and puffing and bent over in exhaustion at the end of each effort, it shoudn’t be utterly gut-wrenching as if you were being chased by a bear. Second, I’ve also done a bunch of eight-second “all out” intervals and only gotten stronger without risk of injury. In only eight seconds, it really is possible to run repeatedly at maximal effort. Third, I’ve found a better way to run these intervals that both makes me stronger and faster while reducing the risk of injury.

A Better Lactate Tolerance Workout

As I mentioned in my earlier post, my cardiologist noted that my lactate clearance left something to be desired– and that this was likely increasing the number of  uncomfortable heart rate spikes I was getting. The protocol that she recommended was one-minute all-out efforts with three minutes of recovery. While the first few intervals might be relatively easy, it wouldn’t take long before my lactic acid levels would be through the roof.

During a short 1-2 minute maximal effort, the body produces a tremendous amount of hydrogen ions and lactic acid. In fact, it doesn’t stop producing them immediately– or, perhaps more correctly, the full impact isn’t discernible in blood tests immediately. When I was being tested by my cardiologist, she took blood sample every minute after I finished an all-out, exhaustive effort and my lactic acid levels just going up and up for 4-5 minutes afterwards. As best I recall, I ultimately peaked around 11 mmol/liter (lactate threshold is commonly about 3-4 mmol/liter). The amount of lactic acid wasn’t the relevant part here– instead, she was curious about how long it would take for my lactic acid levels to start to drop and return to normal. That drop would represent my lactic acid clearance ability– and that’s where things like MCT-1 levels mentioned in my earlier post come in handy. Fortunately, it’s easy to increase this clearance ability– which will make you faster regardless of whether you are a sprinter or an ultra marathon runner.

If you’re a typical endurance athlete, however, you probably spend an inordinate amount of time training below lactate threshold and rarely go above maxVO2. Unfortunately that means you’re highly likely about as badly trained as I was in tolerating and clearing really high amount of lactate. And, as I explained in my earlier post, that may mean that you’re leaving a lot of performance on the table.

So back to my workout. Instead of just sprinting all-out on the flat, I thought that running up an incline instead would simultaneously build a lot more propulsive strength while reducing the impact and the chance of injury. Running up and incline also requires a higher degree of leg lift, improving power that this end of range of motion (something else that is critically lacking in lots of endurance athletes). But running uphill is, of course, slower than running on the flat. So after a certain point, I alternated uphill efforts with sprints on the flat– and I found something interesting: I could run super-fast but I was more exhausted from sprinting on the flats than running up the hills.

So here’s the workout that I’m doing each Tuesday. I choose a location where I have a stretch of flat road and a section of steady hill. For those of you who know Seattle, the epicenter of these workouts for me is currently the corner of 65th Street NE and the Burke-Gilman bike trail. My hill sprints are one-minute straight up 65th Street and my sprints on the flat are southbound on the Burke-Gilman trail (an flat level section of pavement that’s open enough to really run fast). My recovery is a walk-jog back to the intersection. Of course, you can use any intersection where you have a flat section and steady hill.

  1. 1-mile warmup jog
  2. Sprint HARD for one-minute uphill and jog/walk back down to start. Be back at the start at three-minutes (each week, chop 10-20 seconds off the recovery time).
  3. Repeat step 2 two more times (three total)
  4. Sprint HARD for one-minute on the flat and jog back to the start. Be back to the start within the same recovery time as step 2.
  5. Repeat step 2 (uphil sprint)
  6. Repeat alternating sets of steps 4 and 5 four more times (five total). At the end, you should have completed a total of twelve hard intervals.
  7. Cooldown for 1-mile easy.

Depending on your speed and the grade of the hill, this workout should yield a decent distance (e.g. over five miles) and a leave you feeling challenged. Despite sounding awful, it shouldn’t leave you too wasted the next day, although you may feel a little sore in some new places. I find that short sprints like this are not nearly as draining in the long run as lactate threshold workouts. Nevertheless, you really don’t want to do this kind of workout more than once a week.

Mixing up a strength element (uphill sprints) with a speed element (sprints on the flat) makes sense from practical perspective as well. As I described in a different post about using an Alter-G treadmill, baseball pitchers became faster and stronger when they mixed throwing baseballs in practice that were both heavier and lighter than real baseballs. Plus, there are slightly different biomechanical differences between uphill and level running (e.g. knee lift, foot strike, etc) than can’t be fully replicated for the flat through running hills. Lastly, of course, running on the flat incurs a lot more impact forces, so spending half of the workout on relatively low impact hill repeats only lessens the chance of injury.

How to Progress The Workout into “Lactate Stackers”

I knew that this workout was really useful and I wondered whether any other endurance coaches recommended them. While reading through Owen Anderson’s book, Running Science (highly recommended), I remembered that he talked about so-called “lactate stacker” workouts in which you run one-minute segments at a very fast pace (above maxVO2), jog two minutes, and then repeat. This workout is a must for 800 and 1500 meter runners but also important for runners of longer distances to improve lactate clearance.

Owen notes that the hard efforts in the lactate stacker workouts should be run very fast but should not incur undue strain. “A runner should not strain as he or she does this; it is important to be relaxed and yet produce close to maximal power in the leg muscles,” he writes. While you should start with just a few intervals, over time you can build to 15-18 intervals. Owen also notes that most runners find these workouts to be fun.

When I first tried a lactate stacker workout, it was anything but fun. Well, maybe the first interval was fun– but after that, it was a struggle to recover enough. I think I may have done 4-5 intervals before throwing in the towel. No doubt, this had everything to do with my lousy lactate clearance ability. On paper, the only major difference between my lactate tolerance intervals and Owen’s lactate stacker workout was the slightly shorter 2-minute recovery. So to adapt to that shorter recovery, I think the trick is to start with lactate tolerance intervals and gradually shorten the recovery week-by-week from three minutes down to two.

Why This Workout is Important: Training Above Thresholds and How Lactate Accumulates

The beauty to this kind of workout is that it forces you to train at efforts above maxVO2– and for an endurance athlete, training above our different threshold paces (lactate threshold and maxVO2) is highly important.

In reading Owen’s book Running Science, I was fascinated to learn that the traditional tempo run– a 20-minute effort at lactate threshold– is largely unsupported scientifically and yielded relatively modest gains compared to training at higher intensities. Yet so many of us still incorporate a tempo run at threshold in our weekly routine. The bottom line is that, to improve lactate threshold, you have to spend a good deal of time above lactate threshold. And to improve maxVO2, you have to spend time above maxVO2. Unfortunately, it’s really hard to spend a lot of time at running paces faster than maxVO2 (for most of us, maxVO2 this is right around our all-out pace in a six-minute race).

As I noted in my earlier post on lactate training, the body actually uses lactate as fuel– and the cardiac muscles in particular love to gobble the stuff up. But their ability to do that is trainable (with lots of hard speed work) or de-trainable (from only doing aerobic work). As efforts above maxVO2 increases MCT-1, which improves lactate clearance, it’s clear that some work at the highest intensity not only improves your speed at maxVO2 but also improves your speed at lactate threshold. And being able to run faster at lactate threshold improves your ability as a runner in every possible way– even if you only specialize in ultra-marathons and Ironman races.

A Useful Adjunct to Over-Under Workouts

Because of the highly intense nature of lactate tolerance and stacker workouts, you can do too many of them– and I’d probably do only one (or possibly two in unusual circumstances) of these workouts a week between running and cycling. Even with recovery days, that leaves a lot of open time for intense training. Not surprisingly, I think that improving lactate threshold would be a great adjunct to lactate tolerance work– but what kind of workout should that be?

Currently, I’m thinking that over-under workouts are the perfect “other workout” to go with lactate tolerance work. Why? Because, as mentioned above, the most effective way to raise a threshold is to train above that threshold. Over-under workouts do that perfectly with lactate threshold. Also, they are continuous efforts (for me, usually three miles or longer) so it adds an endurance effort that is lacking in lactate tolerance workouts. If you have ever spent any reasonable period of your training doing only shorter sprints, you’ll know exactly what I mean– suddenly, running anything longer than a mile feels like a marathon. Over-under workouts will make sure that doesn’t happen. Plus, running for prolonged periods at paces faster than lactate threshold– and this get worse the higher above lactate threshold pace that you run. So by going just a little bit above and a little bit below threshold, you challenge your body to adapt in a gentler, more sustainable way.

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2 thoughts on “Lactate Tolerance and Stacker Workouts

    • Hi Danielle! Apologies for the delay as I took an extended break from blogging. I was thinking about creating a post about this topic– but then realized that the guys at Compex might not like it. Basically, the process is to get an extra set of cables and snip off the ends where the pads attach. Then solder on some snap pad electrodes (or whatever kind of electrode works with the types of pads you would like to use). It’s pretty easy and definitely cost-effective.


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