In the last installment of The Masters Skater, we demonstrated the fact that an individual's lactate threshold (LT) is a critical factor in limiting (or enhancing) performance. As we mentioned, measurement of LT is usually done in a laboratory equipped to measure heart rate, oxygen consumption lactate and other physiologic variables. Since we all know that lab tests are time consuming, expensive and typically unavailable to most skaters, this installment of The Masters Skater will describe a skate-specific field test designed to help determine a measurement functionally very similar to LT. I developed this test to help you:

1. Assess your current fitness level
2. Monitor your progress during training, and
3. Set up a training schedule that will be optimized for your abilities

Although this test MAY represent your lactate threshold, I prefer to call it a "field test to determine your maximal steady-state skate pace (MSSP)."

It's confusing

There are scores of research articles in various physiology journals espousing the intricate nature of LT testing. And there are arguments over the level of blood lactate that can be withstood for extended periods of time - indeed there appears to be a broad range of blood lactate levels within which individual athletes are able to function, so determining blood lactate levels for individual athletes may not be as helpful as initially thought. In addition, debate rages over how useful the determination of LT is for most athletes, since it is an expensive proposition to do the testing required to measure blood lactate, and blood lactate measurement is currently at the very least a minimally invasive procedure (a needle or other lancing instrument is typically used to poke the finger or an earlobe in order to draw a blood sample) with the potential for infection. With so many dissontant positions on lactate testing (all with a basic agreement that LT is a useful parameter), many sports scientists have tried to couple the basics of muscle physiology during exercise with physiologic responses to produce easy-to-use field tests in place of laboratory tests.

These field tests - which have been used successfully in a number of sports, including track and field, cycling and swimming - have some very common characteristics which have been incorporated into our skate-specific LT, or MSSP, test.

Equipment

In order to do our MSSP test, you will need the following:

1. A flat, consistent-texture surface on which to skate. It will need to be at least 3/8 mile long -- the longer the better. In fact, a paved trail would be an excellent venue for this test; you can change directions during each stage of the test.
2. A day with little or no wind. If wind is present, your data can be effected - making it both unreliable and invalid.
3. A method of keeping track of your speed (see Pacing Device below) during the test.
4. A method of keeping track of your heart rate during the test. This is most effectively done with a heart rate monitor - preferably with memory (see Heart Rate Monitor below).

The test consists basically of the following: After a 10-minute easy warmup, you perform multiple, consecutive 2-minute stages of skating at incrementally-increasing speeds (increasing 1-mph per 2-minute stage). A reasonable speed at which to start the test is 10 mph. You should continue skating; increasing your pace by 1 mph per stage until you can no longer consistently sustain your pace for an entire stage (see Graph). The entire test should take 30 minutes or less for most skaters; of course the duration of the test depends on the maximum speed you can sustain.

A major key to the test is that it should be done continuously; you must continue skating for the duration of the test in order for the results to be valid, reliable and understandable. Any rest periods that you take between stages (for any reason including traffic, a sore back or adjusting your posture) will have an adverse effect on the results. To demonstrate this point, below are a few "pitfalls" that I ran into while validating this test. Watch out for them and you'll save yourself time, as well as reducing the chances of erroneous or misleading results.

I had to perform this test three times before getting "good data." During the first test, there was too much traffic where I was skating, and the draft effect I got from the cars significantly lowered my heart rate during a few trials. The resulting graph didn't make much sense. The message here is that you should make sure you have an unencumbered path on which to skate. That means void of traffic, potholes, stop signs, or anything else that would preclude you from maintaining a consistent pace during 2-minute stages.

During the second test, I encountered a constant wind. It wasn't very fast (3 - 5 mph), but even 3 mph is enough to make a difference in the effective wind drag. The presence of wind made skating in one direction much easier (resulting in a falsely-lowered heart rate) and skating in the other direction much more difficult (resulting in a falsely-elevated heart rate). As a result, heart rate readings did not rise consistently; every time I switched directions, the heart rate would either drop precipitously, or climb unrealistically. I decided to wait another day and do the test during a low-traffic period when the wind was not blowing. The resultant graph was extremely helpful, and fairly clearly described my MSSP (see Graph). Based on my current 10K time trial times on inline skates, the test provided me with a valid measure of my MSSP.

How the MSSP test works

The concept behind this test is that your heart rate and blood lactate levels do not rise in a linear (at the same rate) fashion during exercise of increasing intensity. As the workload you encounter becomes increasingly higher, your lactate level increases, but your heart rate does not increase at the same rate, or to the same degree. The physiology involved in this process is complex, but the results are typically easy to understand: when your heart rate reaches a certain point, your lactate level will increase to a greater degree, therefore a simple graph of workload (speed) versus heart rate will theoretically give you a fairly good representation of your lactate level.

Your MSSP is the point on a graph of heart rate vs. speed where there is a fairly clear change in the relationship of heart rate vs. speed. As you can see in this graph, the heart rate increases in an almost linear fashion with speed. Near the top of the graph, when the speed reaches 21 mph, the heart rate does not increase from thfse previous stage as much as it did during the previous 1-mph increment (stage). This non-linear increase in heart rate (the "breakpoint") signifies my MSSP. Note that the last stage also follows this same pattern - the heart rate does not increase nearly as much as it did during the previous stages.

Note: The "Predicted Y" line on the graph was generated by doing a statistical analysis of the data in a spreadsheet program. If the heart rate continued to rise at the same rate throughout the test, the heart rate data points would fall exactly on the Predicted Y line. Near the top of the graph, it is clear that the heart rate does not continue to rise at the same rate as it did during the preceding stages. This is a helpful tool in visually locating your MSSP pace; you can clearly see where the deviation from "normal" begins.

Before the arguments, disagreements and name-calling ensue, note my initial statement about this test: it is designed to be a field test to determine your Maximal Steady-State Skate Pace, NOT your LT. But for all practical purposes, for most of us (other than skaters on Olympic-level training programs or professional skaters with access to high-level physiology labs) knowing our MSSP should be of more interest than knowing our LT. It provides a measure that we can identify with - how fast we can skate for extended periods. The bottom line is this: knowing your MSSP is important from a functional/training standpoint, since you can do something with that information.

Now, on to a few more specifics about how you can insure good results. Included with the tips are some specifics on how I collected the data in the graphs. The tools I used made the test so easy, it was almost TOO simple.

KISS (Keep It Simple, Skater!)

Try to keep the test as simple as possible. Look for a flat (no inclines and no declines) street with very little traffic and no stop signs. Make sure you know the speed you are skating to within 0.1 mph. Note: if you have someone pace you with a bicycle using a speedometer that reads in "integer" values (12 mph, 13 mph, 14 mph, etc.) instead of more accurate floating-point values (12.8 mph, 12.9 mph, 13.0 mph, etc.), your results can be significantly effected and you can wind up with invalid information - my solution was to use a small, handheld device that constantly updates and displays speed in mph (see description below). To monitor heart rate, use a heart rate monitor that records heart rate in specific time intervals, and can "play back" the results when you are finished. That's all you need - speed and heart rate. Distance is actually not important, since you will be looking at the results of your speed and heart rate values.

Helpful Technology

Pacing Device

The pacing device I used is the Garmin eTrex personal navigator (a small handheld GPS device). The eTrex uses GPS technology (if you don't know what GPS is all about, I suggest you either visit their website, or take my word for it--it's accurate) to constantly keep track of your position and provide you with a display of speed (in mph), distance traveled, and more. The eTrex was amazingly easy to use - and accurate; I measured the course I skated with an odometer several times before using the eTrex, and the eTrex repeatedly measured the distance to within about 60 ft. for a 1-mile course. During my MSSP test, I set the device to display speed; the display was updated approximately once every two seconds, providing me with constant feedback on my pace. If I noticed that my speed dropped below my target for each 2-minute stage, I would skate a bit faster; if my speed was too high, I skated a bit slower. Having constant feedback on my pace was an invaluable tool.

Heart Rate Monitor

The heart rate monitor I used is the Polar Coach; another user-friendly device. I set the monitor to measure my heart rate in 1-minute intervals (by keeping my test time to less than 1 hr. but more than 30 minutes, it automatically selected 1-minute intervals), and it stored my heart rate information for the entire test. I set an interval timer to beep at two-minute intervals, so I knew when to increase my speed for each succeeding stage. When I finished the last stage that I could skate consistently, I returned home to download the data. I loaded the "PC Coach" software that came with the Polar Coach, and without any wires connected from the heart rate monitor to my computer (the Polar Coach uses a unique sound-wave transmission technology to send information to your computer through the microphone), relayed the data from the Coach to my computer. A slick little system.

Using the graphing software that comes with PC Coach, I looked at my graph of heart rate vs. speed (time) and immediately had feedback on my tests. The graph made it pretty clear where the breakpoint of heart rate and speed was located. However, I wanted to make the breakpoint clearer, so I entered the data from the PC Coach program into a spreadsheet and did a minor modification to the information to make the graph more consistent-looking. I used the heart rate from only the SECOND minute of each stage as representative of the heart rate produced by each stage. This made the heart rate increases more consistent, since part of the first minute of each stage was spent increasing my skating speed and trying to "settle in" to that speed. Since heart rate doesn't respond instantaneously, eliminating the heart rate information from the first minute of each stage provides "better" data.

That's all there is to it! Now that you are armed with a field test, you can test yourself to find your MSSP. And armed with that information, you can develop a training program more optimally suited to your ability and fitness level.

We'll address some of the options for using the MSSP results in a training program in future installments of The Masters Skater, but for now... get out there and see how you're doing!