Lactate Threshold - The most important test an athlete will ever take

Imagine an engineer is doing some Mathematical calculations to come up with the maximum load in tons that a bridge can carry. His work tells him the correct formula is

1000 (99-70?ã2) = Tons

He decides that he will just estimate the value of ?ã2 to be 1.4. With this done the calculation is

1000 (99-70*1.4) = 1000 Tons.

If the engineer, (who soon will be fired by the way), had used the exact value for the square root of 2 instead of estimating he would have come up with.

1000 (99-70?ã2) = 5 Tons.

My point is that estimation can have dramatic effects in the long run. Now imagine an athlete is training for a large endurance event such as a marathon or an Ironman. Learning how to measure training intensity is the single most important thing this athlete can do in order to train correctly. Similar to the bridge scenario from above, this athlete should not estimate when it comes to something so important.

Measuring Intensity
Being able to measure how hard you are working can be difficult and confusing. How do we quantify training intensity? We can measure speed, but if I?fm riding side by side with Lance Armstrong at 25 miles per hour, I guarantee that I have a higher training intensity than he does! We can go by our perception of difficulty, (perceived exertion), but some days it just doesn?ft hurt as bad as others. We can use our heart rate, but how do we know what rate is right for us?

All three of the above methods, (speed, perceived exertion, and heart rate), have great potential as intensity measures, but they are useless unless we can somehow put them into context with each of our different physiologies. This is where a lactate threshold test comes in. In order to understand exactly what a lactate threshold test is, let?fs first take a closer look at what lactate is.

Lactic Acid/Lactate Myths
I used to think of lactic acid, (or more accurately lactate) as a horrible substance that accumulated in my muscle cells whenever I exerted myself. In my mind this malicious compound caused my muscles to burn and made me sore the next day. I even spent time and money on products and exercises that supposedly worked to flush this waste product out of my system.

I spent years giving lactate this bad wrap until a very good friend of mine introduced me to the excellent physiology team at the Boulder Center for Sports Medicine. I soon began testing myself and other athletes at the center and slowly I came to understand that lactate is actually a key element used by the body to produce energy, and it is always present in our blood no matter what we are doing. In fact as you sit here reading this article, your body is producing and using lactate to help energize your body.

Lactate Threshold
So if lactate is actually a good thing and it helps us produce energy, why would we care about a threshold point? The more energy the better, right? Well, not exactly. In this case there truly can be too much of a good thing.

To understand this, try to imagine your muscle as a bucket with holes in the bottom. Glucose is being burned via glycolysis and one of the things that results from this process is lactate. This lactate is pouring into your leaky bucket of a muscle. Any lactate that leaks out of the holes goes into the blood stream. As we breathe in and oxygen comes into our bucket, lactate is oxidized and energy is produced. The byproducts of this are carbon dioxide (we breathe out), and H2O, (we sweat). The harder we work, the more lactate is poured into our leaky bucket and the more oxygen we have to breathe in to balance out what is happening. As this intensity rises the bucket begins to get pretty full. The holes in the bottom are maxed out and dumping lactate into the blood as fast as they can. Finally the holes can?ft keep up and we can?ft pull in enough oxygen to use what is in the bucket. As a result the lactate spills over the top, and we hit what I lovingly refer to as the point where you ?gspill your bucket.?h The technical term for this is lactate threshold.

Finding Lactate Threshold
Finding an athlete?fs lactate threshold can be done in many different ways, but if you want to be exact, there is no better way than to have a trained professional conduct a lactate profile in a physiology lab. This is where I depend on the amazing staff at the Boulder Center for Sports Medicine. Not only are they the best at what they do, but they are also wonderful people that will go above and beyond to help you use your results correctly. A lactate threshold test is conducted by putting an athlete on a treadmill or a bike and gradually increasing the speed/watts every 4 minutes. After each 4 minute stage, blood is taken from a finger stick and the lactate is measured. The speed/watts, heart rate, and perceived exertion for the stage are also recorded. This process continues until a significant jump in blood lactate is seen from one stage to the next. This point is defined as the lactate threshold. The following is a graph produced from one of these tests.

As you can see, the athlete above reaches his lactate threshold at an 8:45 min/mile pace, with a heart rate of 174, and a perceived exertion somewhere between 7 and 7.5. Now how do we use this information?

Using Lactate Threshold Data to Improve
At this point the professionals at a professional physiology lab can set up training zones by not only looking at the lactate threshold, but also the data collected leading up to the lactate threshold. This takes a very trained eye and once again shows why it is best to leave this important step to the pros. An example of these zones is displayed above.

Finally, it?fs time for the coach?fs job to begin. Armed with the very precise training zones prescribed by the center, a coach can now set up a periodized training plan that puts the athlete in the right training zones at the right time in order to peak for the main event. The best part of it all is that the coach can have complete confidence in these zones knowing they are set up exactly according to the athlete?fs physiology. Gone are the days of basing training zones off of general formulas such as 220 minus your age.

Being able to measure training intensity is the most important thing an athlete can do in order to improve. Taking a blood lactate test at a professional physiology lab like the Boulder Center for Sports Medicine is the absolute best way to be able to do this. As an athlete, it is the most important test you will ever take.

Coach Howie?fs Tip of the Month
Many of us will soon be entering the base phase of our training for next season. The general train of thought is that the base phase is a time to put in a lot of long slow miles. While I agree with this, I think it is important to remember that high end speed training should not disappear altogether. To keep those speed muscles firing, I suggest putting in very short bouts of high speed at least once a week through out the base phase. For example, in the water, put in some fast 50yd repeats. On the bike, throw in a few 30 second to 1 minute attacks, and on the run try a few 100m strides at 2mile to 5k pace. Happy base training!