A wealth of scientific research has shown that lactate threshold (LT) is an extremely good predictor of endurance performance, but few of us have the equipment and/or facilities available to precisely determine LT. That's unfortunate, because it is important to be able to monitor your fitness over the course of a prolonged training period - checking to see if cycling capacity really is improving after all. Assessing LT every six weeks or so would be a terrific way to do that, but without LT-measuring equipment that is clearly impossible. Pmax: A GREAT PREDICTOR OF PROGRESS

Fortunately, researchers at the Human Performance Laboratory at the University of Queenland in Australia have found another great fitness-checking technique, and all you need to utilize is a modern cycle ergometer or CompuTrainer tm which provides your power output in Watts. With a cycle ergometer or CompuTrainer tm, you can determine something called max power (Pmax), which in many cases will be as good as the best lactate variable at assessing your overall fitness. Here's the scoop on the Queenland research:

The Australian investigators asked 24 female cyclists and triathletes to take part in their study. The athletes were about 29 years old, weighted 132 pounds, stood 5'7", and were roughly as fit as good-quality, university cross-country runners, with average VO2max readings of 48.1 ml/kg/min (1). On an exercise bike, each of the female athletes completed a five-minute warm-up and then began cycling with a rather paltry power output of 50 Watts.

Every three minutes, the intensity was jacked up by 25 Watts, however, and the athletes had to keep going, moving up the intensity ladder in 25-Watt increments, until they were too exhausted to continue. Oxygen consumption, maximum oxygen-consumption rate (VO2max), ventilation rate, and blood-lactate levels were monitored continuously throughout the rides, and Pmax was defined as the highest power output a cyclist attained before stopping the test (note that Pmax is not the maximal power an athlete can generate in a short burst of intensity activity, as you might think, but rather the power level a cyclist reaches just prior to exhaustion during a bout of exercise with steady increasing intensities). Pmax: A GREAT PREDICTOR OF PROGRESS

 From the blood-lactate responses produced during the tests, the Australian researchers calculated the athletes' traditional lactate thresholds, as well as some unique indicators of lactate dynamics, including: (1) LT1, the power output mmol/liter above resting levels, (2) LTlog, the power output at which plasma lactate begins to increase when the logarithm of lactate level is plotted against the log of power output, (3) LT4, the power output at which lactate reaches a concentration of 4 mmol/liter, and finally (4) LTD, the lactate threshold calculated by the "D-max" method. The latter variable - LTD - has nothing to do with Ford automobiles but appears to have great utilty and deserves a Cycling Research News story of its own. We'll describe what LTD actually is and indicate how it can be used in an upcoming issue of CRN.

To learn more about What To Do About Pmax: A Great Predictor of Progress (the full article can be read by purchasing Vol.1 Issue 1 of Cycling Research News) and many more cycling related topics.