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.  

Most cyclists accept the idea that tapering can enhance performance; what is less certain is how tapering actually works and what form of tapering is optimal.

By deifinition, tapering is considered to be a tarining technique which strives to eliminate training induced fatique while maintaining - or even upgrading - training- associated adaptations (1). In practical terms, tapering usually involves a diminishment of training volume, intensity, and/or frequency over a period of two to 28 days before an important competition. It is clear from the available scientific research that tapering can promote improvements in performance-related physiological variables such as VO2max and lactate threshold speed, as well as in race times (2).

Why does tapering work so effectively? Exercise scientists have noticed that tapering tends to magnify many of the physiological changes observed during systematic endurance training. For example, several studies have shown that tapering bolsters glycogen levels in muscles and updates muscular concentrations and activities of oxidative enzymes. The surplus glycogen accuring as a result of a tapering period increases fuel availability during prolonged exercise, and the hoisted enzyme concentrations allow usuable energy to be created at higher rates during exertion, fostering higher-intensity effort during competition.

Although there is little doubt that tapering is beneficial, there continues to be debate about what kind of taper produces the greatest overall adaptations. Some athletes think of a tapering period as a time for easy training; they don't change their volume or frequency of training very much but do cut out most of the intense work they have been doing. Others take several days off during their tapering phase but otherwise train in a fairly routine manner. Finally, some competitors cut back drastically on overall volume of work (by eliminating and/or shortening workouts) while maintaining a solid core of intense training (although there is a concern that intense effort may increase fatique, it is believed that the retained high quality work provides an added upward push to competitve fitness).

Muddying the taper debate a bit is the notion that tapering might influence different types of muscle fibers in discrete ways. There is not nuch information available in this important area, but in a recent study researchers were able to show that the Type-IIA muscle cells of highly trained swimmers produced greater peak forces and were significantly larger after a 21-day taper; in contrast, the Type-I ("slow-twitch") fibers of the natatorian were not larger but probably were able to contract at a higher rate, compared to before the tapering period (3). Since tapering seems to be able to produce fiber specific effects, it is possible that a tapering program which revolved around cutbacks in volume might have a different effect on performance and on the three key muscle-fiber types (I, IIA, and IIB), compared with a tapering period which focused on paring away intensity. It is not beyond the realms of possibilty that an athlete with a preponderance of one type of muscle cell might need an entirely different kind of taper, compared to a competitor with a different muscle-fiber composition.

To find out more about the utility of various tapering programs and the effects of commonly used tapers on the different muscle-fiber types, Patrick Neary and his colleagues at the University of Alberta in Canada recently divided 22 well-trained, male endurance cyclists into three groups (4). After seven weeks of intensive training, a control group (N = 7) simply continued training rigorously. Meanwhile, one of the two experimental groups maintained training intensity while lowering overall volume (N = 7), and the second experimental group held volume steady but trimmed exercise intensity (N = 8). A simulated 40-K time trial was completed by all cyclists before and after the one-week tapering periods.

Going into the tapering period, the cyclists were fit, with an average VO2max of 60.9 ml'kg-1min-1. The seven-week training period leading up to the taper had been rugged for all of the cyclists, with the program featuring four 60-minute workouts per week at an intensity of 85 to 90 percent of maximal heart rate. The control group continued to train in this way during the tapering period, whereas the first experimental group kept up the 85-90 intensity but backed down to workouts lasting for 45, 35, 25, and then 20 minutes during the tapering week. The second experimental group preserved the 60-minute workouts but lowered intensity from 85 percent of max heart rate to 75 percent, 65 percent, and then 55 percent of max over the course of the four workouts. Members of both of these experimental groups rested completely for one day at the end of the tapering period before embarking on the 40-K time trials. For these tests, the cyclists used their own bicycles, mounted on wind-loaded cycling roliers fitted with a stabilizing bar attached to the handle bar for safety. The air pressure of the bicycle tires was checked before and after each ride and also before and after the taper to make certain that maximum pressure was maintained throughout.

To learn more about Optimal Tapering (the full article can be read by purchasing Vol. 1 Issue 2 of Cycling Research News) located in the back issues section of our site, and many more cycling related topics.