A cyclist's psychological state can also cause heart rate during exercise to move hither and yon, and even a cyclist's position on the bike, caffeine intake, and sleep patterns can produce changes in ticker tempo (3). As a result, many cyclists have become increasingly interested in utilizing power output as the key monitor of training quality and race performance (Greg Lemond got the power ball rolling in the early 1990s when he first began to use power as a key training variable). Using power instead of heart rate appears to make sense, because the mechanical power output produced by cyclist to move a bike forward is the key variable which determines the actual demands placed on the cyclist during exertion (4); it is a much-better indicator of total physical stress than the simple beating of the heart.

Fortunately, power output can be measured directly on the bike with the use of a "mobile crank dynamometer" (5). Two power monitors seem to be dominating the cycling marketplace right now - the SRM and the Power Tap. Although their costs are considerable, these devices are extremely attractive, because they can display cadence, wheel speed, distance covered, energy expenditure, and ambient temperature (just the SRM), in addition to power output, as you train and compete.

Naturally, these devices should be both accurate and reliable if they are to be truly useful to you. Let's take a moment to look at these two terms. Accuracy refers to how close the readings on the SRM or Power Tap are to your true power outputs. If, for example, you are carrying out an interval workout and your true work interval intensity is 300 Watts, it would not be good if your SRM or Power Tap provided readings of ~360 Watts. True, some experts argue that the actual number on your power meter is not so important, as long as the power device is reliable (i.e., gives readings which are highly repeatable; we'll discuss reliability in a second).  POWER

This reminds us of the "The amp goes to 11" line in the movie Spinal Tap, which referred to an ampliflier which possessed a volume scale of 1 through 11 (instead of the usual 1-10), even though it was not any louder than traditional amps. Just as the 11 on that amp was the same as 10 on other magnifiers, a 330 on a power meter might be the same as a true 300, and as long as that relationship was consistent you could still track changes in your workout quality. The problem could come when you attempted to predict performance, say in a 40-K time trial, for example. If a published scientific study revealed the relationship between power output at vV02max and 40-K performance, you would not be able to draw a valid conclusion about your own 40-K potential if your power monitor provided inaccurate readings.

The word reliability refers to the repeatability of measurements. For example, your power monitor is totally reliable (although inaccurate) if it gives a reading of 350 Watts every time you cycle at a true power output of 300 Watts. If you are always at 300 Watts but your power device gives up an array of different numbers, then the gizmo is unreliable.

To learn more about power, heart rate, & competitive cycling (the full article can be read by purchasing Vol.2 Issue 3) and many more cycling related topics. Simply enter power, in the "search archives" box, or enter any subject you wish to learn more about.  POWER

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.

Indeed, several decent studies have found that strength training has no positive impact on cycling performance. In research carried out at the University College of London, for example, 12 weeks of heavy duty resistance training failed to improve cycling power (1). In this British investigation, 17 physically active subjects (11 males and 6 females, average age 29) trained three times per week, with each session consisting of four sets of six repetitions at the maximum load that could be lifted six times; this turned out to be approximately 80 percent of the maximum load of a single lift (80 percent of the "1 RM"). The subjects recovered for one minute between sets and had their 1-RM strength re-evaluated at the beginning of each week (as it advanced, the weight used in the sets correspondingly increased).

The 12-week training program had a major impact on the subjects' leg-extension strength, which vaulted upward by 160 percent for the men and 200 percent for the women. However, the strength training regime had no positive effect at all on maximal power output during cycling, either at 70, 80, or 100 rpm.

In a separate piece of research carried out in the Human Performance Laboratory at the University of Queensland in Australia, 21 well-trained female cyclists (age 18-42) who had been training for an average of 2.5 years were randomly assigned to either a resistance-training group or a control group (2). Subjects in the resistance training group carried out two strength workouts per week on top of their usual endurance work and completed 24 total strength sessions over a 12-week period. Each strength workout started with a five-minute general warm-up, five minutes of stretches, and about 28 warm-up "squats." The workout itself consisted of three to five sets of squats at intensities ranging from 2 RM to * RM; three-minute recovery periods were sandwiched between the sets. The total amount of endurance training was equivalent between the resistance and control groups.

As it turned out, the 12-week program was extremely effective at boosting 1-RM squatting strength, which soared by 36 percent in the experimental group (control subjects failed to improve). However, the strength training was unable to improve cycling performance; average power output during a one-hour cycling time trial was unchanged in the squatters after 12 weeks.

So, why do cyclists and their coaches often claim that strength training improves their fatigue-resistance, hill-climbing prowess, attacking ability in races, and closing sprint capacity during races? Well, research has shown that there is a solid connection between the anaerobic power of cyclist and their competitive ability. In research carried out with United States Cycling Federation athletes from different categories at the University of Tennessee-Knoxville, investigators found that cyclists in the highest performance category had the loftiest anaerobic power (3). Of course, anaerobic power is something which conventional strength training is supposed to reliably increase.

In addition, it is important to bear in mind that not all of the research on strength training and endurance cyclist performance has been negative. In a unique study carried out by noted researcher Asker Juekendrup and his colleagues from the United Kingdom and the Netherlands, a group of competitive cyclists who substituted explosive strength training for about one-third of their usual endurance training upgraded maximal power output and time-trial performance in just four weeks, compared with individuals who continue with their usual endurance training (4).

In this Dutch-English inquiry, 14 experienced cyclists took part; six were placed in the experimental, explosive-training group, while the other eight athletes served as controls. The athletes were accustomed to training for about 12 to 13 hours per week and had been training at a high level for an average of five to eight years. During the experimental period, both groups averaged nine hours of training each week, but for the explosive group 37 percent of the total time consisted of explosive training. The control group carried out only typical endurance training.

The explosive sessions consisted of high-rep, low-resistance, quick-as-possible movements, with 30 reps per set for each exercise. Resistance was set so that the athletes could keep up their speed of movement during the first 20 reps of the 30-rep sets, with some power lost over the last 10 reps. If the athletes could finish an exercise with a constant rate of movement, the resistance was increased. Each explosive workout proceeded as follows:

(1) 10-minute warm-up on bike at 75 percent of heart-rate max

(2) Squats: 2 sets of 30 reps, with short recovery between sets

(3) Leg Presses: 2 sets of 30 reps, with short recovery

(4) Leg Pulls: 2 sets of 30 reps

(5) One-Leg Step-Ups: 2 sets of 30 reps

(6) 10 minutes of cycling at 75 percent of heart-rate max

After step 6 was completed, steps 2-6 were performed one more time.

As mentioned, the average power output achieved during a one-hour time trial increased significantly after just four weeks of training in the explosive group but failed to budge upward for the control, endurance-training-only cyclists. In addition, maximal power sailed upward after four weeks for the explosive fellows but was stagnant in the endurance riders. Interestingly enough, the explosive group cyclists were also able to maintain their "short-term performance" (the ability to cycle all-out for just 30 seconds) over a nine-week period, while the strictly endurance-trained athletes lost short-term performance power. Also, the explosive athletes tended to become more efficient over the study period (i.e., could complete more work per minute for each unit of energy expended), while the endurance cyclists did not. The explosive strength training was a winner!

To learn more about Can Strength Training Boost Your Cycling (the full article can be read by purchasing Vol. 1 Issue 1 of Cycling Research News) located in the back issues section of our site, and many more cycling related topics. A subscription to

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.  

Some research has linked low blood-glucose concentrations with fatigue and bad performances (2). In addition, it is widely known that pre-race ingestion of carbohydrate can suppress lipolysis, i.e., can inhibit the breakdown of fat for energy (3). This is potentially bad, since some fat is needed to supply the energy demands of prolonged, strenuous exercise. In theory, the pre-race carbs might - some-what paradoxically - increase the risk of glycogen depletion by shifting muscle metabolism away from fatty acid breakdown over a sole reliance on carbohydrate! What should the competitive cyclist do?

To find out, Asker Jeukendrup and his colleagues from the Human Performance Laboratory at the University of Birmingham in the United Kingdom recently recruited nine endurance-trained cyclists to take part in a study which looked at the effects of ingesting various amounts of carbohydrate during the hour before arduous exercise (4). Average age of the cyclists was 29.6, and they were fit (VO2max=64.1 ml'kg-1. min -1 and Wmax=360 Watts). Each athlete reported to the Performance Laboratory on two separate occasions prior to the beginning of the experiments. During the first visit, VO2max and Wmax were determined; on the second trip, the cyclists familiarized themselves with a time-trial procedure which involved 20 minutes of cycling at 65 percent Wmax (about 72 percent of VO2max), followed immediately by 40 minutes of intense cycling.

After this initial pair of visit, the cyclists completed four times trials, with at least three days between trials. 45 minutes before the beginnings of the trials, the subjects consumed 500 ml (about 17 ounces) of a beverage which contained either 0 grams of glucose (the placebo drink), 25 grams of glucose (a 5-percent solution), 75 grams of glucose (a 15-percent solution), or 200 grams of the simple sugar (a hefty, 40-percent concoction). The order in which the drinks were provided was random. The trials were conducted between 7 and 9 A.M. after an overnight fast. The placebo was artificially sweetened so that subjects could not tell that it contained no sugar, and energy-free orange flavoring was added to all drinks to make them taste similar. PRE-RACE NUTRIENT

To learn more about What To Do About Pre-Race Nutrient Intake (the full article can be read by purchasing Vol.1 Issue 6 of Cycling Research News) and many more cycling related topics.

If this supposition were true, it would represent a real astonishment. Cyclists and their coaches are used to thinking that dehydration can hurt performances, with drop-offs in cycling ability believed to occur whenever fluid deficit is greater than 2 percent of body weight (1). How likely is a 2-percent fall-off? Consider this: If you weigh 160 pounds, your fluid deficit would have to exceed 3.2 pounds, in theory, for your cycling capacity to fall. Many cyclists absorb just .6 liters of fluid per hour across the walls of the small intestine during exercise. During hard effort or when the temperature is relatively high, cyclists can easily lose 1.6 liters of water per hour from their sweat glands. That's a net loss of one liter (2.12 pounds) of water every 60 minutes. Thus, it would take just 3.2/2.12 + 1.5 hours to exceed the 2-percent threshold. Higher sweat rates - and lower absorption rates - would of course cause the threshold to be reached more quickly.

Because of serious concerns about dehydration, the American College of Sports Medicine has published guidelines concerning fluid replacement during exercise (2). The basic idea underpinning these fluid-intake touchstones is that cyclists and other athletes should attempt to replace sweat losses during exercise, and a common recommendation is to consume about 600 to 1200 ml of sports drink per hour in hopes of achieving this goal. Sports drink is chosen over water because it can satisfy an athlete's simultaneous needs for water and carbohydrate during extended exercise.

However, researchers have noticed that many athletes drink far less than the recommended amount during exertion. In one study, endurance runners took in just 400 ml of fluid per hour during a marathon, a rate of intake which was well below both their average sweat rates and the aforementioned goals established by the American College of Sports Medicine (3) (incidentally, for our 160-pound athlete mentioned above, this would cause the 2-percent barrier to be crossed after just 75 minutes of exercise). Other research has shown that professional male cyclists do a poor job of replacing fluid losses during competition, building up fluid losses of 2.1 to 4.5 kilograms (4.6 to 9.9 pounds) within a race (4). Note that a 9.9 pound loss represents about 1.24 gallons of water lost via the sweat glands and respiratory system during exercise. This would easily be greater than 2 percent of body mass, unless the cyclists happened to weigh more than 495 pounds! IS DEHYDRATION OVER-RATED

How can endurance runners complete marathons, and how can pro cyclists finish competitions with high placings when they are apparently so dehydrated? The answer to these questions, according to some exercise specialists, is that the performance-damping effects of dehydrated are greatly overrated. The dehydration doubters point to a study in which a restricted fluid intake produced no fall in performance for cyclists during a one-hour time trial (5). In a separate piece of research, a lack of fluid consumption led to no decrements in power during maximal, 15-minute cycling exertions (6). In addition, the top finishers in prolonged endurance events such as the marathon and triathlons are often he individuals who are the most dehydrated (7). If dehydration were truly performance-limiting, one would not expect this to be the case.

It is possible to make a strong argument that being dehydrated would actually be helpful from a performance standpoint. Here's how the pro-dehydration logics goes: If you are dehydrated, it means that you are slowing for aid stations less often - or that you are changing your posture on the bike less frequently (to take in fluid). This should improve average speed. In addition (and here's the strongest point), the reduction in body mass associated with being dehydrated lowers the energy cost of movement, thus allowing a specific cycling speed to be maintained at a smaller fraction of VO2max. The speed then becomes easier to sustain, and a cyclist may in fact move up to higher speeds which correspond with the percent of VO2max associated with the well-hydrated state.

Overall, cycling in a dehydrated state can improve something called the power-to-mass ratio, or P/M. This ratio has been directly linked with cycling performance, especially during efforts which involve significant amounts of hill climbing: As P/M increases, so do performances (8, 9, & 10). To express it simply, if you can improve your max power output without increasing your mass ( or if your increase in mass), your performances will be upgrade. In addition, if you can reduce mass without hurting your power, your performances will also be enhanced (because P/M will again be bigger number). IS DEHYDRATION OVER-RATED?

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There is a widespread belief that warm-ups enhance athletic performances, and most cyclists agree that warming up before competitions and challenging workouts is a good idea. What they don’t know is exactly how to warm up.

In fact, there is no “stone tablet” to tell cyclists how their warm-ups should be structured in terms of intensity, duration, and mode (active, passive, specific). In addition, the optimal duration of the time period between the end of a warm-up and the onset of exercise is unknown (and probably varies according to warm-up type).

There are many conflicting views about warming up. A popular conception, for example is that warm-ups should raise muscle temperatures in order to facilitate stronger muscular contractions. However, the advantages of hiking muscle temperature prior to endurance cycling have never been demonstrated in a peer reviewed, controlled study (1). In fact, under warm environmental conditions such an effect would appear to be dis-advantageous.

A key concern among exercise scientists has been how warming up influences the VO2 response to exercise – the rate at which oxygen consumption rises when an intense workout or competition begins. This appears to be very important, because a rapid increase in the oxygen supply to muscles at the beginning of strenuous exercise enables muscles to create energy aerobically at high rates during even the early stages of effort. Along these lines, some research has shown that warm-ups which include exercise sustained at above the lactate threshold improve the VO2 response (2, 3, 4, & 5). Naturally, such findings provide support for the idea that warm-ups should be rather intense. WARM-UPS

However, as you might expect, there is also evidence that intense warm-ups can actually harm subsequent performance (6), presumably because there is a danger that such warm-ups can be either too intense or because they may be sustained for too long. There are also a number of studies which have failed to detect any benefits at all for active warm-ups (7, 8, & 9).

A recent review suggested that low-intensity warm-ups (at 70 percent of VO2max or below) are beneficial for performance in “intermediate-length” events (those lasting from 10 to 300 seconds) – but that high intensity warm-ups (> 70 percent of VO2max) actually harm intermediate-length performances, unless an adequate recovery is taken between the end of the warm-up and the beginning of the actual exertion (10).

As you can see, scientific research has in the past provided a fairly limited amount of information about how to warm up in an optimal way. Fortunately, two new studies add to our knowledge of warming up.

In one investigation, carried out by researchers from the University of Wisconsin-La Crosse, Vrije University in Amsterdam, and the European University of Madrid, eight well-trained cyclists used three different warmup strategies prior to a 3-K cycling time trial (11). The cyclists were pretty fit (VO2max = 60 ml.kg-1.min-1), and they normally trained from 10 to 15 hours each week. Their average age was 31 years,and all were experienced at 3-K
time trials. WARM-UPS

All eight subjects performed four 3-K time trials on a racing bicycle attached to a windload simulator equipped with a heavy flywheel (Findly Road Machine, Toronto, Canada). Performances on this kind of set-up have been found to simulate roadcycling performances quite closely (12, 13, 14, & 15). The first of the four efforts was a habituation trial designed to make certain that each athlete was ready for the task at hand. The warm-up for this trial
incorporated five minutes of cycling at an intensity of about 50 percent of VO2max.

The next three 3-K time trials, performed in random order, were preceded by three different warm-up strategies:

(1) No warm-up at all (the athletes simply sat on their cyclesfor six minutes and then began the time trial),

(2) An “easy warm-up” (a 15-minute warm-up that included five-minute segments at 35 percent of VO2max, 40 percent of VO2max, and 45 percent of VO2max, followed by two minutes of rest before the actual time trial), and

(3) A “hard warm-up” (an 18-minute warm-up that included five-minute segments at 35 percent of VO2max, 40 percent of VO2max, and 45 percent of VO2max, and then three minutes at about lactatethreshold intensity, followed by a six-minute rest before the beginning of the time trial).

Note the rather long rest between the end of the hard warm-up and the beginning of the time trial! While this might seem to be counter-intuitive, it represents an acknowledgement that some research has shown that intense warm-ups hurt performances. By including the longer recovery, the Wisconsin- Amsterdam-Madrid scientists were giving the hard
warm-up a chance to “work.”

As it turned out, performance was poorest after no warm-up: Without a warm-up, the time required forthe 3-K time trial averaged 274.4 seconds.

However, there were no performance differences at all between the easy and hard warm-ups, each of which produced 267-second 3-K times (about 2.5- percent faster than the no-warm-up condition). Paradoxically, a key reason for this lack of difference between the hard and soft warm-ups may have been the long recovery after the hard warm-up, which allowed heart rate and oxygen consumption to sink – during the six-minute recovery – to levels observed toward the end of the easy warm-up (thus taking away the “priming” effect of the hard warm-up). The three minutes at lactate threshold in the hard warm-up were not enough to induce significant fatigue (which would have made hard-warm-up performance worse, compared to easy-warm-up performance), and the six-minute recovery took away the heart-rate and oxygen “edges” that the hard warm-up could have provided. WARM-UPS

Interestingly enough, the three different warm-up types (no, easy, and hard) yielded identical times over the last 1500 meters of the 3K (showing, in effect, that the no-warm-up athletes used the first 1500 to warm up). In addition, there was a significant lag in the rate of increase of VO2 during the nowarm- up time trial, compared with the other two cases (remember that VO2 response is considered to be an important potential benefit of warming up).

Why does a lack of warm-up hurt the oxygen response – and thus performance? Of course, as you can imagine, blood flow to working muscles (and thus oxygen flow to same) can be augmented during an effective warm-up, but is not advanced by sitting around. After a good warm-up, oxygen flow to the muscles is more ample at the beginning of exercise, compared with the poor- or no-warm-up case, and thus the VO2 response is better. In addition, some research has shown that the heart (the body’s “oxygen pump”) behaves abnormally at the beginning of demanding exercise when no warm-up has been performed (16) – and that these abnormalities are eliminated when a warm-up is conducted (17). Abnormal beating of the heart can reduce cardiac output and thus downgrade the amount of oxygenated blood flowing to the muscles. When the flow of oxygen to muscles is reduced, the rate of aerobic energy creation also falls, and this can hurt performance significantly.

The finding that performance time and power output over roughly the last half of a 3-K time trial are similar, regardless of warm-up type (indeed even when there is no warm-up), is quite interesting. It suggests that the effects of warm-up are primarily displayed during the first two minutes or so of strenuous exertion – and then tend to disappear afterwards (provided, of course that the warm-up does not promote earlier-than-expected fatigue). This does not mean that warm-up is relatively unimportant. In a four-minute competition, for example, what happens during the first two minutes is extremely relevant to the final outcome. It does imply, however, that the effects of warm-up would be strongest in events lasting less than two minutes – and perhaps nearly imperceptible
in competitions lasting – shall we say – 40 minutes or more?

In a second, new study carried out at the University of Wales and Manchester Metropolitan University (both in the United Kingdom), 12 well-trained cyclists tried out four different warm-up strategies prior to a seven-minute performance trial on an electrically braked cycle ergometer (18). The cyclists were relatively fit (VO2max = 58 ml.kg-1.min-1), and their averageage was 34 years. The warm-ups consisted of: WARM-UPS

(1) Nothing – no exercise at all (technically, of course, this is not a warm-up),

(2) 10 to 12 minutes of moderate-intensity cycling at about 80 percent of lactate-threshold intensity,

(3) Six minutes of very strenuous cycling at an intensity which was half-way between lactate threshold and VO2max, and

(4) Nothing except 30 seconds of all-outsprint cycling (!).

Unfortunately, a 10-minute period of rest followed each of these warm-ups - prior to the sevenminute time trials. Apparently, the researchers were concerned that the heavy exercise of warm-up #s 3 & 4 might produce fatigue during the subsequent trial and thus incorporated this long, rather-unnatural recovery (we use the term unfortunately at the beginning of this paragraph because other research has suggested that extended, i. e. 10-minute, recoveries can sometimes thwart performance).

During the seven-minute trials, the subjects were constrained for the first two minutes at an intensity of 90 percent of VO2max and a pedal rate of 90 rpm (note that this is a bit like an intense warmup). For the last five minutes of the trials, the athletes attempted to sustain maximal intensities.

As it turned out, average power output during the seven-minute trial was the same (~ 339 Watts) after the moderate and heavy warm-ups; both were about 2.7-percent better than the “control” warm-up, which included no exercise at all. The sprint warm-up, which incorporated just 30 seconds of effort, with power outputs rising to 600 to700Watts, produced a level of performance during the seven-minute trial which was no better than the control situation.

Although the two studies just described provide little support for the idea that high-intensity warm-ups are superior to moderate- or low-intensity affairs, bear in mind that the unusual lengths of the “breaks” between the hard warm-ups and the time

                                                         A second study carried out in the
                                                         United Kingdom compared the
                                                         effects of four different kinds of
                                                         warm-up.

trials (six minutes in duration in the first study and 10 minutes in the second) may have obliterated the benefits associated with the more-fiery warm-up periods. Current thinking suggests that a significant portion of the warm-up should be very intense if the ensuing workout or competition will be carried out at a high intensity. The in-vogue theory is that “firing up” the brain and spinal cord with very high-level activity will prepare the nervous system to coordinate the muscles more efficiently during the top-quality work which is to follow. WARM-UPS

In order to improve our understanding of the effects of warm-up intensity on athletic performance, particularly during high-intensity exertions, scientists at the University of British Columbia in Canada and the University of Otago in New Zealand studied nine male senior rugby-union players (19). Average age of the rugby athletes was 22 years, mean weight was 176 pounds, and average VO2max checked in at a decent level of 60.4 ml.kg-1.min-1.

On four separate days, the athletes completed four different trials in the laboratory. Each test started with a range-of-motion evaluation of the hip, knee, and ankle, but this evaluation was then followed by 15 minutes of warm-up treadmill running at 60, 70, or 80% of VO2max (three trials) – or no warm-up at all (the fourth trial). In all four cases, a series of stretches for the leg muscles were then carried out for three minutes, followed by a second range-of-motion evaluation and then an all-out test on the treadmill.

For the no-warm-up trial, the rugby athletes simply sat in chairs for 15 minutes before completing their three minutes of stretching. The popular proprioceptive neuromuscular technique of “contract-relax” stretching was utilized in all cases, and special efforts were made to unkink the hamstrings, hip flexors, quads, and calf muscles. For the all-out treadmill test which followed the stretches, the athletes simply ran for as long as possible at a velocity of 13 km/hour (about 7:26 per mile pace) – on a very punishing 20-percent inclination.

As it turned out, the active warm-ups really did warm up the athletes’ bodies, compared with the chair-sitting “warm-up.” Basically, the 60- and 70-percent-of-VO2max warm-ups elevated body temperature (measured via rectal probes) by almost a full degree Centigrade, and the 80-% VO2max rehearsal upped temperature by another half-degree.
Heart rate followed a similar trend, with average heart rate highest during the 80-% treadmill effort, significantly lower in the 70-% treadmill run, lower still in the 60-% ramble, and lowest of all during chair-sitting. However, because three minutes of stretching followed the warm-up runs and preceded the all-out tests, heart rates were about the same in the 60, 70, and 80 groups when the all-out exams began. WARM-UPS

Stretching by itself had no effect at all on range of motion; there was no increase in range of motion when stretching was coupled with the chairsitting. However, ankle dorsiflexion (a movement which stretches the Achilles tendon and calf muscles) and hip extension were strongly promoted by all of the three warm-up intensities. In contrast, knee flexion (a measure of quadriceps flexibility) was not upgraded by any warm-up condition, and hip flexion (an indication of hamstring flexibility) was augmented only by the 80-%-VO2max warmup.

The effects of the various warm-ups (or no warm-up) on high-level performance were extremely interesting. Basically, the 15 minutes of running at 60 or 70% of VO2max led to situations in which the rugby athletes lasted longer than 70
seconds on the steeply inclined treadmill. In contrast, the 80-% warm-up resulted in just a little over 60 seconds of staying power, which was significantly worse than the 70-% affair and not significantly better than no warm-up at all!

Why was the highest-intensity warm-up not as good as the more inchmeal preparations? One possible explanation might be that the more strenuous warm-up fatigued the athletes to a greater extent, compared with the easier preambles, but this would be a very tenuous conclusion to make. Because stretching and range-of-motion measurements followed
the 15-minute gambols, the athletes did not start their all-out tests until at least five minutes had elapsed post-warm-up. In fact, when the all-out tests started, heart rates were exactly the same in the 60, 70, and 80 groups, and feelings of fatigue should also have been similar.

Does this mean that you should not exercise intensely during your warm-up if you intend to perform intensely during your workout or race? Absolutely not! Bear in mind that the warm-ups utilized by the British-Columbia and New-Zealand scientists were continuous in nature, and there is no reason for you to emulate this continuity. 15 continuous minutes at 80% of VO2max are certainly not necessary to fire up the nervous system prior to exercise, nor are they needed to elevate heart rate appropriately. For the close-to-one-minute-in-duration all-out effort analyzed in this study, a 15-minute warm-up, with three to four high-intensity segments lasting for 30 to 40 seconds each intertwined with easy overall exercise for the remaining 12 to 13 minutes, would have been entirely more appropriate. WARM-UPS

What does all of this research mean to you as a cyclist? For races or tough workouts lasting for extended periods of time, the warm-up becomes less important, as previously mentioned. If you are going to be cycling intensely for an hour or more, for example, a warm-up can consist of about 10 minutes of easy cycling, with perhaps one minute of effort at the pace you will establish at the beginning of your race/ workout. That should be all you need! Bear in mind that warm-ups which last longer or are more intense may actually deplete muscle glycogen to a significant degree, and you’re going to need that precious stuff during your effort!

What about shorter workouts and races? Remember that a warm-up should always prepare you specifically for what you need to do in your race or workout. A 15-minute, continuous warm-up at 80% of VO2max, followed by 10 minutes of quiescence, has little resemblance (either in time or intensity) to a time trial lasting for just three or four minutes, and it should not be used. A better match for a relatively short-duration effort would be a warm-up which includes three to four short (30-second) segments at goal intensity, to fire up your nervous system, along with about 10 to 12 minutes of general activity – with no long break between the warm-up and your exertion.

Let’s focus for a moment on that break between the end of the warm-up and the beginning of a quality workout or race. Research shows that oxygen consumption generally falls back to close to normal when the break lasts for longer than five minutes. Thus, you should not employ a break lasting longer than five minutes (remember that oxygen flow to your muscles is a good thing, providing more aerobically created energy at the onset of your effort). As you’ll see in a moment, there is evidence that the break should be even shorter than this.

The only exception would be in the case in which your workout consists of 10- to 15-second sprints (or your race is only 10 to 15 seconds in duration!). The quality of such efforts depends on the establishment of normal phosphocreatine levels in your muscles, and it takes longer than five minutes for phosphocreatine concentrations to rev back to normal after intense warm-ups. Very short intervals/races require longer breaks between warm-up and the start of activity (remember to stay “loose” during such breaks, however, pedaling lightly and stretching, if needed). WARM-UPS

One of the best studies concerning the effects of warm-ups on performance is a “classic” carried out by Dr. Walter D. Andzel of the Physical Education Department at Kean College of New Jersey in 1978 (20). Andzel monitored 20 female physicaleducation majors aged 18-23 from the school’s swimming, field hockey, and basketball teams. These athletes warmed up by exercising on a treadmill with gradually increasing speed until a heart rate of 140 beats per minute was attained. Each individual continued exercising at that level for two additional minutesand then rested for either 30, 60, 90, or 120 seconds. The performance test followed, with each participant exercising for as long as possible at a scalding intensity of 95 to 100 percent of VO2max.

The warm-up pattern which included only 30 seconds of rest prior to the hard exercise was clearly superior to the other strategies, with resting for 60 seconds being almost as good. Taking longer-than- 60-second recoveries after warm-up produced significantly poorer performances.

The shorter rest periods of 30 and 60 seconds promoted higher heart rates at the beginnings of the all-out efforts (120 and 110 beats per minute, respectively, versus 99 and 89 beats per minute for the 90 and 120 seconds of rest). That’s actually a good thing: Your heart can take it – it won’t get tired more quickly because it has to begin your exertion at a higher rate of beating, and the higher heart rate indicates that your cardiovascular (oxygen-transport) system has remained activated and is ready to work when your intense exertion begins. If you wait longer than that, there is a risk that the mobilization of your cardiovascular system will be reduced. Oxygen transport is important during the early stages of tough exertion, and so post-warm-up recoveries should generally be brief. ©

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Unfortunately for most cyclists, determination of lactate threshold is not so easy. For precise determination of threshold, a visit to an exercise-physiology laboratory is mandated, and the test requires time and a fair amount of money (including the cost of traveling to the lab). But - no worries: There is a much-simpler way to assess 40-K fitness. All a cyclist has to do is cover 5K as fast as possible. That's right - just 5K. Recent research indicates that for well-trained cyclists the speed sustained in a 40-K race will be 92 to 94 percent of the average velocity attained in a 5-K test. Furthermore, the power output displayed in a 40-K race can be predicted quite nicely with the following equation: Power Output(40-K Race) = .58(power output in 5-K trial) + 89.4 The power output in both cases (40K and 5K) is expressed in Watts.

Thus, a simple field test - the performance of an all-out 5-K trial - will not only provide an adequate estimation of current fitness; it will also predict rather neatly how well one will perform in a 40-K race. EXPLOSIVE

If you carry out challenging interval workouts during your cycling training, you are studying the true nature of fatigue. After all, you have probably had the following experience: You decide on a workout at 40-K pace, say 10 X 2K in 3:23 each (we've selected a standard training session and a reasonable distance and velocity - and thus time - for each work interval; in this case, the speed is 35.5 kilometers per hour, or about 22 miles per hour). Your warm-up goes well, and you're off and cycling!

The pace you have chosen is an ambitious one, but you are feeling great the first time through the 2-K distance, and you cover the initial 2000 meters in 3:15. The second one is 3:18, the third 3:21, and from the fourth one on you are struggling a bit to hit your target of 3:23 each time. For the most part, you stay on track, but one interval, we'll say the eighth, slides up to 3:29.

The ninth feels really tough, but you hang in there an dproduce a 3:23. You have reached the point in the workout at which fatigue should be close to maximal. After all, you are a believer in the traditional concept of fatigue. You know that as you continue to cycle quickly, for one work interval after another, your intramuscular pH is dropping fast, reflecting the tide of hydrogen ions which are flooding your muscle cells (1). That devastating fall in pH is interfering with the release of calcium ions into your muscles' sarcoplasmic areas (2), making it much-more difficult for your muscle fibers to contract forcefully (3). As a result, adhering to planned pace is becoming a major undertaking. FATIGUE FORENSIC

And then, something magical happens! At the point when muscular fatigue is greatest, when pH has bottomed out, when calcium ions have been locked away for the day, when muscle contractility has ebbed, you uncork your best 2K of the day - a 3:12! Who said that cycling does not have its magical moments?

Huh? If muscle fatigue is truly a function of metabolic events happening inside muscles, that last 2000 should have been the slowest, not the fastest interval of the day. Our views of fatigue - and of what determines cycling velocity during workouts and races - must be wrong!

Indeed, that is what recent research carried out by Tim Noakes and colleagues at the University of Cape Town, the University of Stellenbosch, and the Sports Science Institute of South Africa is telling us. In this new investigation, eight healthy males (average age = 22 years) completed "anaerobic capacity" tests in the laboratory on a Monark friction braked cycle ergometer (4). To gain a better understanding of the nature of fatigue and of pacing strategies during high-power exertions, South-African researchers used an element of deception with the subjects. Specifically, the young men were informed that they would be completing four 30-second maximal trials, as well as one 33-second and one 36-second maximal effort on the bike. In reality, they completed two trials of 30 seconds, two tests of 33 seconds, and a duo of 36-second exams.

The deception took place in the following way: Prior to one of the 33-second tests, the cyclists were told that it was actually a 30-second exertion, and the same was true for one of the 36-second affairs. The researchers hoped to determine whether the subjects would subconsciously alter pace or strategy during the "informed' 36-second trial (when they were told that the trial would last for 36 seconds), for example, compared with the "deception" 36-second trial, when the cyclists thought they would only be cycling for 30 seconds. The cyclists were allowed to watch a clock during all of their maximal exertions, but - ingeniously - the scientists had programmed the clock to run more slowly during the deception 36-second trial, so that it would tick 30 "seconds" during what was really a 36-second time frame. FATIGUE FORENSIC

You might expect that the cyclists would ride with more power, at least initially, during the deception-36 trial, compared with the informed-36 trial (since they thought that the deception-36 trial was going to be shorter in duration), but the results were more ineresting than that. As it turned out, power output was exactly the same in the informed and deception 36-second trials, right up until the 33-second point, but then power fell significantly over the last three seconds of the deception trial!

How should we interpret that? Since the cyclists were able to perform more work when they were reliably informed about the duration of exercise, compared with when they had been deceived, some internal factor, not located in the muscles, must have controlled power ouput. If "peripheral fatigue" (fatigue centered in the muscles, as according to traditional theory) was the true factor controlling performance, then power outputs should have been exactly the same in the informed and deceived 36-second trials (because the extent of muscle fatigue would have been the same in these two trials of equal duration).

To learn more about FATIGUE FORENSIC: WHAT REALLY MAKES YOU SLOW DOWN (the full article can be read by purchasing Vol. 2 Issue 5 of Cycling Research News) located in the back issues section of our site, and many more cycling related topics. A subscription to Cycling Research News is another way to receive valuable information about cycling.

Let's start with the link between glycogen and fatigue first. It is true that when your muscle glycogen stores reach a certain low level as you bike along at a high intensity, you are going to become too tired to continue - there is simply no way to get around it (1). Oddly enough, however, this sunken glycogen level is not zero: when your sinews reach the point at which they are unable to work, there is still a fair amount of glycogen fuel lying around.

This seems strange, of course. It doesn't seem right that not much exercise-boosting glycogen can be stored in your body in the first place - maybe just 2000 calories worth or so - and yet that not all of the socked-away stuff can actually be utilized to sustain exercise. You can store a seemingly infinite amount of fat in various regions of your frame, but you get to stockpile a rather meager amount of glycogen, and you don't get to use the entire, modest amount that you put away - even when you are trying desperately to win a race or set a PR.

Those of us who are accustomed to operating a motor vehicle certainly find this situation to be unusual, too: it's like having a car stop running completely when there are still a couple of gallons of gas left in the tank. The shutdown makes sense, however, when you realize that it is probably a protective mechanism. If your muscles ever reached rock-bottom glycogen quantities during a workout or race, their overall metabolism would be impaired, the possibility of injury would probably increase, and it would be very difficult - after exercise ended - for the muscles to sustain themselves and successfully begin the post exercise recovery process. Glycogen: Not Juct A Carbohydrate Ny More

Since the exhaustion-inducing glycogen level is not zero, exercise scientists have searched for the glycogen concentration which actually does stop cyclists in their tracks. Interestingly enough, they have found that this level can vary considerably from athlete, with some bikers becoming exhausted when glycogen stockpiles are 70-percent gone - and others requiring a significantly greater wipe-out before exhaustion is reached (2).

As mentioned, glycogen concentration is linked with several other things, in addition to the onset of fatigue. Notably, your muscle-glycogen content regulates your rates of carbohydrate and fat breakdown at the beginning of a competition or a good workout. If your muscle-glycogen depots are well-stocked, for example, your glycogen "burning" rate will be very lofty as you begin your session or race; if they are medium to low, glycogen breakdown will proceed at a significantly lower rate, and you will be relying more heavily on fat to keep you going (3).

This is true even if you gulp down large quantities of sports drink at the last minute, just before you start cycling, in hopes of giving your glycogen-poor muscles a carbo-boost. A couple of studies have shown that athletes with low muscle-glycogen concentrations at the beginning of a bout of exercise have elevated rates of fat oxidation, even when hyperglycemia (a high level of blood glucose) is induced (4).

Such findings have suggested to some researchers that some factor, originating outside muscle, must determine the rate at which muscles breakdown fat in response to shifting glycogen levels during exercise (this "factor" could be either neural or hormonal in origin). If this is true, muscles must have some way to communicate with the nervous and/or endocrine systems, and many investigators have hypothesized that muscles are able to send out a "signal" as their glycogen concentrations fall (5). In theory, this signal leads to an increase in circulating noradrenaline levels and a decrease in circulating insulin. Noradrenaline boosts fat breakdown, and insulin tends to shoot carbohydrate into muscles, so overall result would be a stimulation of fat oxidation and a potential decrease in carbohydrate utilization. Glycogen: Not Just A Carbohydrate Any More

Of what practical use is this information to you? The answer is that if muscles can truly send out a signal (or signals) in response to changing glycogen levels, then the quality of your intense workouts and competitions could vary - right from the beginning of exercise - on the extent of your muscle glycogen storage.

This would be rather startling. After all, we already know that when muscle-glycogen levels get pretty low, exhaustion is reached. But it has not been clear that moderate (non-exhaustion-inducing) depletions of glycogen might slow down efforts right from the beginning of a workout or race. It has been assumed that muscles operate quite well until they reach a critical (low) point of glycogen concentration, after which performance falls. If this is not true, then maxing-out glycogen would become an even-more important issue than if it has appeared to be in the past. Even in relatively short bike races (lasting less than 60 minutes or so), glycogen pile-ups could be quite important.

Glycogen concentrations can even determine how effectively muscle cells respond to rigorous training.

To learn more about Glycogen: Not Just A Carbohydrate Any More (the full article can be read by purchasing Vol.2 Issue 2 of Cycling Research News) located in the back issuessection of our site, and many more cycling related topics. A subscription to Cycling Research News is another way to receive valuable information about cycling. CYCLING RESEARCH NEWS.