This is a typical graph of an blood lactate vs work intensity chart looks like, but I recognize that their is a lot going on here. While I believe most people have the general idea here, but I think if we take an in depth breakdown of this graph, you’ll be able to understand the makeup of our “strength” workouts.
Let’s start with the solid line with data collection points. The line represents blood lactate levels compare to intensity. It is no surprise that as we run faster, the amount of lactate produced is greater. Remember back to our physiology discussions and lactate is a by product of glycolysis (the breakdown of glucose). At lower intensities it can be “recycled” at rates close to production. The faster we run, the less the recycling can keep up. Now, it’s important to note here that lactate or lactic acid in itself isn’t our cause of fatigue, but fatigue and lactic acid amounts are closely associated with each other.
Then, you see the two vertical dashed lines. The first, labeled “Aerobic Threshold’ and represents where lactic acid is first rising above baseline levels. Typically, this signifies when carbohydrate becomes the majority fuel source over fat. For beginner and poorly aerobically developed runners, as well as those who are carbohydrate dominant with their diets, this will occur at pretty easy paces. Regardless of population, marathon pace will be beyond this point, it just might be a matter of how far beyond.
The second dashed line is labeled MLSS, or in this particular graph, anaerobic threshold. MLSS stands for Maximal Lactate Steady State and aptly, is the last point at which lactic acid levels will stay steady per a given pace. Essentially, once you are at a pace beyond that point, your lactic acid levels will continue to rise, even if you stay at a given pace. Regardless of running population, marathon pace will be below this. In fact this point typically represents a pace that you can maintain for about an hour. So for most people this is about 10k to 15k pace. For elite and world class athletes, this pace might represent 20k to half marathon pace.
Along the top of this chart you see “zones” labeled. The zone on the far left is your easy and regeneration (or recovery) running. The middle is your moderate to high aerobic running. This would include harder long runs, tempo runs (marathon pace), strength, and half marathon pace work at increasingly harder paces approaching MLSS. The third zone is your fastest running and would include 10k and faster paces.
Knowing what these points represents is crucial to understanding how and why workouts are set at the intensities they are. Knowing that increases the likelihood of a runner not going overboard on paces when knowing that faster doesn’t necessarily stimulate the desired training adaptation.
For this discussion, I want to focus on strength and why it’s important to adhere to specified paces. First, let’s discuss the terminology of the strength workout. We describe strength as MP-10 in shorthand. Reading that would be Marathon Pace minus 10 seconds per mile. Or if your goal marathon pace is 9:00 per mile, your strength pace would be 8:50 per mile.
Now, some of you can see already where you get into trouble- you are running your tempos at your strength pace. I’ll admit, lines can become blurry.
Over the last few years, I have come to conclusion that the four hour marathon is where these lines may not be a perfect fit.
However, that is not a go ahead to go full throttle, either. There has to be some sort of guidelines to adhere to.
In nearly all of our marathon training programs, you won’t be engaging in the strength workout phase until you’ve started doing longer tempos. I consider longer tempos anything that is taking you over an hour. Now, given that definition, you’ll naturally settle into a pace that’s going to be slower than your MLSS deflection point. So, clearly the pace you are running for the tempo is slower than MLSS pace. If not, then you are just blatantly running too fast and need to either dial it back or evaluate what your goals are. This isn’t to say that you are faster than what what your marathon pace is, but we can fix that too.
How you ask?
Well, let’s go back to our 9:00/mile example. Let’s say that’s your goal marathon pace, but you’ve been cheating down most of your tempo runs to 8:50. Ok, fast, but at that pace not crazy (the faster you get the less room for error you will have though). So, you get to where you are starting your strength workouts and since you’ve been averaging 8:50 pace, you settle on doing your strength at 8:40 pace.
That’s fine, I don’t necessarily see a problem with it, BUT here is what you have to pay attention to.
- Don’t lose sight of what the goal of the strength work is. Refer back to HMM
- Does this pace now go beyond where your MLSS pace would be? If so, then that’s faster than the desired pace or effect of the workout. If you know right away, that 8:40 pace is right around your 10k pace, then it’s too fast. We just did that segment during the speed work! However, many of you don’t know what your other race paces are, so the next two questions will be more practical.
- Does this now affect your ability to complete the strength workouts? This may be measured in a couple different ways. One, if you progressively get slower throughout the workout then your strength is too fast. Two, if your recovery jogs become recovery walks or get extended in length/time, then your strength pace is too fast. Your strength repeats and rest jogs should be about equal pace throughout the entirety of the workout (not necessarily effort though)
- Does this affect the pace at which you can complete your tempo runs? Let’s say you willed your way through a strength workout and kept it fairly even, but now you are really dreading that tempo run a couple days later. You may be able to power your way through for a couple weeks, but if your strength is too fast, then over time you will lose the ability to recover enough to maintain those tempo runs.
How should strength workouts feel?
The simple answer would be, “harder than your tempo runs, but easier than your speed.” To expand on that, you will often hear marathon pace runs described as comfortably hard, but I think that depends on ability and what your definition of “comfortably hard” is. To me, 8-10 mile tempos (which is about where you’ll be once you start the strength) should be a significant effort, but one that you feel you could extend a few miles if you really had to. Speed work is a much more anaerobic effort, in which you’ll get the “lactic burn.” So, you may be feeling in your legs or even like your lungs are going to catch on fire. Strength should feel like your balancing a fine line between being a sustainable effort vs. crashing and burning.
Granted this might take a couple times to get down, but that’s why I try to always start people out with 6×1 miles or even 800’s at strength pace. The biggest mistake I see people make on the first strength workout is that they overestimate their fitness and underestimate the recovery. They are coming off doing a bunch of speed work that’s way faster (but a lot more relative recovery) and see that they are doing repeats and a pace only slightly faster than marathon pace. So, usually through a combination of running too fast and not maximizing the recovery jog, they get to the 3rd or 4th one and realize they’ve dug a hole they can’t get out of. Remember, speed work usually brings acute discomfort. It’s usually an eye opener from the get go. Strength workouts should sneak up on you. The same effort for the last few should feel fairly hard compared to the first one or two. That’s when you’ve done it right- think slow cooker. You are slowly building that lactic feeling. Never fully recovering from the repeat prior and letting the discomfort slowly add to each successive repeat.
Strength workouts are probably the hardest to adjust too. With speed, you know you need to run hard. With tempos you know that you need to know what marathon pace feels like and you spend the most amount of time practicing it. With strength, you’re really in a tweener zone. Somewhere between really hard and kinda hard. The biggest thing is to learn from mistakes quickly and try to follow the guidelines I have provided. If you can do that, you’ll get it down, not to mention, find out what your abilities may be.