Lactate Threshold 2 and Where it Fits in Your Program
Lactate Threshold Is Not the Hardest Pace You Can Hold
Threshold might be the most misused word in CrossFit programming. I see four 3 minute AMRAPs labeled as threshold work, and on the podcast this week Kyle talked about athletes telling him they were at threshold for a whole workout with heart rates in the upper 180s. We only had time to scratch the surface there, so I wanted to dive into this topic in a bit more depth. If you want to listen to that conversation, it can be found here: https://open.spotify.com/episode/3pUjaSp7QPGPsBlUpfwM5k?si=Ub5vt-acT6WF0ILxWS20tw
The short version is that lactate threshold is a specific, targeted pace with a specific purpose. When it is trained well, it is one of the biggest reasons an athlete can keep racing deep into a workout. When it is trained poorly, it just another met-con.
Threshold is a targeted pace, not your hardest one
When I talk about threshold, I am referring to your second lactate threshold (LT2). It sits somewhere around the pace you could hold for a 45 to 60 minute effort, depending on how fit the athlete is. That is different from the hardest pace you can hold, because you are intentionally working in a small, targeted pace window, and the purpose of that pace is to improve your true endurance.
When we build a foundation of endurance, lactate threshold is the last point on the speed continuum where you are still almost entirely aerobic. This aerobic development sets a base for an athletes ability to perform in the sport both inside of individual workouts along with recovery between events.
It should feel like you are working at a decent clip. If something comes up, you can speak a short sentence, but you cannot carry on a conversation. That is the best check I know of for whether the training is appropriate during the interval. You should also be above the point where you can nasal breathe. If you can nasal breathe during a threshold session, you are going too slow for this stimulus.
How to find your threshold without a lab
In my opinion, the best way to find your threshold is a time trial in that 45 to 60 minute time domain. Threshold is different in different environments, so you should establish it for each modality you plan to train. If you are going to do threshold running, you need a running test. If you are going to do it on the rower, you need a rowing test, and so on.
One thing has to be in place before you test: the mechanical resilience and tissue tolerance to actually sustain a pace for that long. If an athlete does not have much exposure to an implement, giving them a threshold tester or session on it is not going to get them much. Because most crossfitters don't train modalities at a high enough frequency to push hard for 60 straight minutes, I tend to drop to 45 minutes as the prescribed effort.
The other way to do this without lab testing is to establish your max heart rate and train at about 90 percent of it for continuous amounts of time.
How I structure threshold sessions
Most of the threshold sessions I write are between three and ten minutes of continuous work, typically with a four to one or three to one work to rest ratio. As the intervals get longer, I move toward four to one. If an athlete is working for eight minutes, a four to one ratio gives them two minutes of rest. A three to one ratio would give them closer to two minutes and forty seconds, and that extra time is usually not needed to recover inside of a threshold session.
How long I keep an athlete at threshold depends on the modality. For running, I typically program somewhere between 20 and 30 minutes of threshold work in a session. On an Echo Bike, a rower, or a ski erg, I am comfortable going as high as 45 minutes, because there is a lot less pounding and tissue damage on those machines.
Running is at such a premium in CrossFit, and it creates so much separation, that we need it in the plan for the vast majority of athletes who want to compete in person, whether that is at the Games or their local competition. So I blend running with the machines. A session might look like this
3 x 4 minute run at 45 min effort, 1 min walk
3 x 4 minute EB at 45 min effort, 1 min walk
That is 36 minutes at lactate threshold with only 12 of them running, and the central system still gets the full benefit. The heart doesn't distinguish between the types of exercise we are doing.
If an athlete has a running priority, that same idea shifts the workload towards the run:
4 x 4 min row at 45 min effort, 1 min walk
Once they get better at holding threshold, I flip the order and put the rowing or biking first. Now they go into the run already fatigued, which teaches them to be more efficient and makes the threshold stimulus more sport specific if compromised running is a weak point. I only do that once an athlete has done enough threshold work to be confident with their paces.
Why mixed modal work breaks the steady state
This is the part that gets misused the most. Threshold training depends on holding a steady effort, and most mixed modal work does not allow that. Breathing rhythms change significantly from movement to movement, and athletes run into local muscle fatigue before their engine is the limiter. If you do three minutes of burpees for three or four rounds, you will probably hit tricep or pec fatigue, and possibly hip flexor fatigue. On an Echo Bike, you likely will not, unless you lack adequate exposure to the bike.
There is an exception. Athletes who are skilled enough in the sport, typically individual athletes at the semifinals level and above from a conditioning and work capacity standpoint, can often keep a steady state with movements that have light external loading. Wall balls can almost always work in a threshold session. Box jumps can work for the right athlete, and dumbbell snatches work for almost everyone in that group. Beyond movements like those, things get dicey, because breath holding and grunting start to show up and change how the athlete moves.
What threshold work does for you on the competition floor
Threshold work dramatically improves your body's ability to clear lactate. Where I notice this most is in transitions. At in person competitions and in online qualifiers, transitions can be your recovery time if you are well conditioned. If your lactate clearance is robust, you recover much more in those windows.
It also lets athletes recover while they are still working. They can shift down a gear and operate at a slightly slower pace than they would like to race at, and after 30 to 60 seconds at that pace, they can get right back into a hard effort and race again. Threshold development raises the floor on your movement speed, and it helps you hold your racing efforts because you are recovering during the transitions instead of falling apart in them.
Where threshold fits in the season
How much threshold work an athlete does depends on the athlete. For athletes who are more engine limited, it is a big part of the offseason, and that is where we spend the most time developing it. As we move into the season and work that is specific to the sport becomes more necessary, threshold work moves into a retention phase.
Threshold work is not overly fatiguing for CrossFitters, but it takes a big chunk of time. Because of that, it takes away from the time available to train everything else, and that tradeoff is a big part of why it belongs where it fits best in the year.
Generally speaking as athletes get into the fall and winter, I start to put the final touches on LT2 by having the recovery happen while moving at prescribed paces. This is the last uptick in difficulty that they get prior to moving into more sport focused work.
An example of the differences for this would be
to
12 x 3 min EB at 45 min effort, 1 min EB at 8-10 cadence slower than working pace
This small change makes a huge difference and allows the recovery work discussed earlier to happen even more readily.
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