Knowing your blood-lactate concentrations during training can help you in a number of ways, but there's always been a big problem with reckoning lactates during workouts. The necessary equipment has been very expensive - and much too cumbersome to drag to the track or cross country course for a training session. In addition, most of us don't have easy access to an exercise physiology laboratory equipped with lactate-measuring equipment, so we can usually only guess how much lactate is simmering in our bloodstreams when we do 'tempo' workouts or hurry through intervals on the track.

Until now. An American company called Sports Resource Group, Inc. is distributing a convenient little device - the Accusport=81 Portable Lactate Analyzer - which is small enough to hold in the palm of your hand and cheap enough so that you won't have to take out a second mortgage on your home if you want it. Best of all, the little thing is pretty accurate, giving readings almost identical to those obtained using heavy-duty, upper-price-bracket lab equipment.

Recently, scientists at Ithaca College in New York put the little monitor through its paces. Thirty-one well-trained cyclists (16 males and 15 females) ranging in age from 16 to 43 years exercised at different intensities while their blood lactates were checked by both the Accusport=81 and a 'big boy' - the YSI Model 1500, which is a standard piece of equipment in many university exercise labs.

The Accusports=81 (two were used in the study) fared extremely well. For example, when the subjects were at rest, the YSI gave lactate readings of about 1.17, while the Accusports=81 checked in at 1.24 and 1.44. At 70% VO2max, the old reliable YSI settled at 2.14, while the Accusports cozed up just a tiny notch to 2.24 and 2.26. During a nearly maximal test which pushed the YSI needle to 13.21, the Accusports=81 were not far away at 13.16 and 13.95. And during a Wingate Test of Anaerobic Capacity, the YSI hung in at around 14.52, while the Accusports=81 were only a tick or two away at 14.66 and 14.86. Such readings are so close to the YSI 'gold standard' that the only conclusion to draw is that the Accusport=81 can be used confidently and successfully by athletes during workouts.

Good enough so far, but that still leaves us with two key questions. How would you use the Accusport=81 if you actually bought one? Could the pocket-sized device actually help make you a better runner or cyclist?
The answer to the latter question is definitely yes, although you have to remember that the Accusport=81 is not a magical contraption which will automatically make your training better - and your performances higher. You do have to use the appliance wisely.


Putting the little Accusport=81 to use
One application immediately became apparent at this year's Annual Meeting of the American College of Sports Medicine (the same venue at which the news about Accusport=81 reliability was announced). In a paper presented at the Cincinnati meeting, researchers from the University Estacio de Sa and the University Gama Filha in Brazil used lactate measurements to accurately predict 5-K performances.

In this Brazilian study, 28 middle- and long-distance runners ran for five-minute intervals at various speeds on the track until they were able to find a speed (in metres per minute) which produced a blood-lactate reading of 4 millimoles per litre (when blood was withdrawn 30 seconds after the end of a five-minute interval). All 28 athletes also participated in a 5-K race.

The Brazilian scientists unearthed a very interesting relationship: once the running speed which produced a lactate concentration of 4 millimoles/litre was identified, it was very easy to predict 5-K race velocity. In fact, all one needed to do was add about 14 metres per minute to the speed which caused lactate to ascend to 4. In practical terms, here's how this relationship might work for you: After running at various velocities during 5-minute intervals, you find - after a fair amount of finger pricking - that running at six- minute mile pace (268 metres per minute) gives you a blood lactate of about 4 mmol/litre. That being true, your predicted 5-K pace is 268 + 14 = 282 metres per minute, or 5:42 per mile. If you haven't run a 5K in a long time, or if you've only run 5Ks under pretty horrid environmental conditions which don't give you a true picture of your 5-K ability, that can be a pretty useful pace to know about.

For one thing, predicting your 5-K pace leaves you room for a pretty nifty workout. Using the example from the preceding paragraph, you could run some 1200s at 282-metre per minute tempo, which would mean completing each 1200 in 1200/282 = 4.25 minutes (that is, 4 minutes and 15 seconds). Another nice thing to do would be to work on your lactate-threshold running velocity (LTRV) for six weeks (a six-week macrocycle) and then re-test yourself to see which running speed coincided with 4 mmol/litre of lactate. If you've done the right thing, your LTRV should be higher, which would also mean that your 4 mmol/litre speed would also be higher. If your Accusport=81 tells you that your 4mmol/litre pace is indeed a nicer number, you'll have confidence that your training is progressing as expected.


Other applications
We shouldn't forget that there are other ways to employ Accusport=81, too. For example, you can check your lactate at the end of an interval workout designed to volumise VO2max. If your lactate has climaxed beyond about 12 mmol/litre or so, you'll know that your workout has been far too intense, and that in fact you've been trying to overly stimulate your muscles to develop their anaerobic propensities rather than their good aerobic characteristics.

You can also check your lactate after all of your fairly intense workouts. If these are sessions which you repeat on a regular basis during training, you'll be able to obtain some valuable information. For example, suppose you like to carry out 800 metre repeats at about your 5-K race pace or a little faster, a workout which you conduct every two weeks or so. If you take your lactate level at the end of the last interval, and do this after every such workout, a declining lactate level over time will show you that your fitness is indeed improving.

And of course, you can use the Accusport=81 to try to locate your 'real' LTRV, rather than relying on the familiar guesstimate of '12 seconds per mile slower than your 10-K race pace'. However, be aware that this will require a lot of finger pricking, since you'll actually have to graphically plot your lactate concentration at a pretty wide range of running speeds (each of which will require a poke) in order to find the velocity at which lactate levels start to really climb. Be aware, too, that choosing an LTRV from such a graph is not necessarily a precise endeavour, so much so that you may be better off just sticking with '10-K pace minus 12'. Also, you should know that scientific research supports the idea that training at exactly 10-K pace, which is slightly faster than LTRV, is actually better for raising LTRV than training at LTRV itself, and of course you can identify your 10-K pace without using the Accusport=81 at all. The bottom line is that you can run 10Ks fairly regularly and use your race pace for LTRV-enhancing workouts, instead of navigating through the ins and outs of blood-lactate measurement.


Mistakes
And one thing you'll definitely want to avoid is the popular practice of 'lactate-zone' training, or LZT. In this form of training, you may attempt to carry out a certain percentage of your running or cycling below a lactate level of 2 mmol/litre, another percentage between 2 and 4 mmol, another fraction between 4 and 8, and yet another percentage above 8 (the percentages and actual lactate numbers vary from lactate guru to guru). Please remember that there's no scientific research at all to back up this manner of training, even though it certainly sounds and looks scientific when it is presented in book or article form. There is absolutely no way at all for the endurance athlete to know what percentage of training should be carried out within a particular range of lactate readings, nor is there even a way to identify the optimal lactate zones!
It's also important to avoid a common lactate pitfall, which is to believe that LTRV occurs automatically at a lactate level of 4 mmol/litre. The truth is that some athletes are at LTRV at this lactate concentration, but many reach LTRV at just 2 to 3 mmol/litre - or at 6 to 7. If your LTRV is at 6 mmol/litre but you train at 4 mmol/litre, believing that 4 is your LTRV, your training will definitely not be optimal for heightening LTRV!
You also should be aware that the readings on the Accusport=81 are good - but not absolute. In other words, the Accusport=81 readings will vary around your true lactate level. This is not a big problem, though, and it certainly doesn't mean that the Accusport=81 is not a useful device. What it does mean is that if your lactate level is 8.5 after a particular workout, and 8.7 after the same workout a few weeks later, that does not really foretell that your fitness has declined; the change may actually represent nothing more than the small, random errors made by the Accusport=81 as it tries to gauge your true lactate level. Such small mistakes of a few tenths of a point are normal and are to be expected, so what you really need to look for are bigger moves.

For example, if your lactate is 8.5 when you run at a particular pace or conduct a specific workout and 7.5 a few weeks later when you do the same kind of running, you can be very confident that you've raised your LTRV. Basically, reliability testing of the Accusport=81 suggests that you should view lactate changes as real if they exceed about .5 mmol/litre. This means that if your lactate has been consistently at 6 mmol/litre when you run at six-minute per mile pace but suddenly changes to 5.6, you shouldn't be very confident that that's a real change. If it goes to 5.4, on the other hand, you can trust your little Accusport's contention that you've actually improved. Once you're at 5.4, though, don't get too happy until you reach 4.9 or lower - or too sad unless your lactate soars above 5.9.

However, you should be also be aware that diet, fatigue, recent training, and dehydration, can all affect lactate readings. For example, a sudden increase in carbohydrate intake can boost lactate levels, without any changes in your basic fitness. Being more tired than usual or being somewhat dehydrated can do the same thing. As we mentioned earlier, the Accusport=81 is not foolproof. It can be a valuable addition to your training but should not be relied upon as a perfect indicator of your fitness. As always, the true test of how good you are is competition.

The Accusport=81 has a number of useful features: It can remember up to 101 previous lactate readings, which is very important for the individual who's forgetful about recording data. In addition, the batteries last for over 1000 tests, and it doesn't take the Accusport=81 long to compute your lactate once a droplet of blood is inserted.

Owen Anderson