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Purpose: To use eye-tracking technology to directly compare information acquisition behavior of experienced and novice cyclists during a self-paced, 10-mile (16.1 km) time trial (TT)., Method: Two groups of novice (n = 10) and experienced cyclists (n = 10) performed a 10-mile self-paced TT on two separate occasions during which a number of feedback variables (speed, distance, power output, cadence, HR, and time) were projected within their view. A large RPE scale was also presented next to the projected information and participants. Participants were fitted with a head-mounted eye tracker and HR monitor., Results: Experienced cyclists performed both TT quicker than novices (F1,18 = 6.8, P = 0.018) during which they primarily looked at speed (9 of 10 participants), whereas novices primarily looked at distance (6 of 10 participants). Experienced cyclists looked at primary information for longer than novices across the whole TT (24.5% ± 4.2% vs 34.2% ± 6.1%; t18 = 4.2; P < 0.001) and less frequently than novices during the last quarter of the TT (49 ± 19 vs 80 ± 32; t18 = -2.6; P = 0.009). The most common combination of primary and secondary information looked at by experienced cyclists was speed and distance, respectively. Looking at 10 different primary-secondary feedback permutations, the novices were less consistent than the experienced cyclists in their information acquisition behavior., Conclusions: This study challenges the importance placed on knowledge of the endpoint to pacing in previous models, especially for experienced cyclists for whom distance feedback was looked at secondary to, but in conjunction with, information about speed. Novice cyclists have a greater dependence on distance feedback, which they look at for shorter and more frequent periods than the experienced cyclists. Experienced cyclists are more selective and consistent in attention to feedback during TT cycling.

Unlabelled: The psychological construct of affect is proposed to significantly contribute to pacing decisions during exercise. Borg's RPE scale, another important regulator of work rate, is criticized as an inadequate measure of the multiple perceptual responses experienced. This study aimed to examine power output distribution and associated changes in affect, self-efficacy, perceptual cues, HR, and respiratory gases during both 16.1- and 40-km self-paced cycling time trials (TT). Secondly, the differentiation between physical perceptions of exertion and sense of effort in self-paced exercise was investigated., Method: Fifteen trained male cyclists completed 16.1- and 40-km TT using a CompuTrainer cycle ergometer. Time, power output distribution, affect, self-efficacy, physical RPE (P-RPE), task effort and awareness (TEA), HR, and respiratory gases were measured throughout each TT. Linear mixed models explored associations of these variables with power output distribution and the relationship between P-RPE and TEA., Results: Similar pacing strategies were adopted in the 16.1- and 40-km TT (P = 0.31), and the main effects were found for affect (P = 0.001) and RER (P < 0.001). Interactions between affect (P = 0.037) and RER (P = 0.004), with condition, indicated closer associations with power output distribution in 16.1 km than that in 40 km TT. P-RPE was not significantly different from TEA (P = 0.053)., Conclusion: A significant association between affect and power output distribution suggests that affective responses are task dependent even in self-paced exercise, and a greater association is demonstrated in higher intensity, 16.1 km TT. Furthermore, physical perceptions of exertion are not clearly differentiated from the sense of effort in self-paced exercise.

Aim: The present study investigated the effects of high and low glycemic index (GI) 24 h recovery meals on the physiological responses and subsequent athletic performance, following a glycogen depleting protocol., Methods: Ten well trained cyclists (age, 33.6±7.4y, height, 175.3±7.6 cm, weight 74.5±8.2 kg, and VO(2max), 60.5±6.0 ml∙kg(-1)∙min(-1)) participated in two trials in a randomized cross- over design. On day 1, subjects performed a glycogen depleting protocol after which they then consumed either high or low GI recovery diets over the next 24 h, which provided 8 g.kgBW(-1) of carbohydrate. On day 2, the subjects returned to the laboratory, 2- 3 h postprandial, to perform a 40 km time trial (TT) on the Velotron cyclePro© ergometer., Results: No difference was observed in TT performance times between the high GI (93. 5±9.29 min) trial and the low GI (90.7±11.1 min) trial (t=1.1; P=0.35). Additionally, no differences in carbohydrate (F=1.1, P=0.37) fat (F=1.1, P=0.40) oxidation or blood glucose concentration (F=0.9, P=0.5) was observed., Discussion: The results of the present study suggest that the ingestion of a high GI carbohydrate 24 h recovery diet following glycogen depleting exercise, has no greater effect on endurance performance than consuming a low GI carbohydrate 24 h recovery diet. It may be concluded from these results that, provided enough carbohydrate is consumed during a 24 h recovery period, there is no difference in subsequent endurance performance.

The purpose of this study was to investigate the alterations in serum heat shock protein (Hsp) 70 levels during a 15-consecutive-day intermittent heat-exercise protocol in a 29-year-old male ultra marathon runner. Heat acclimation, for the purpose of physical activities in elevated ambient temperatures, has numerous physiological benefits including mechanisms such as improved cardiac output, increased plasma volume and a decreased core temperature (T (c)). In addition to the central adaptations, the role of Hsp during heat acclimation has received an increasing amount of attention. The acclimation protocol applied was designed to correspond with the athlete's tapering period for the 2007 Marathon Des Sables. The subject (VO(2)max = 50.7 ml.kg(-1).min(-1), peak power output [PPO] = 376 W) cycled daily for 90 min at a workload corresponding to 50% of VO(2)max in a temperature-controlled room (average WBGT = 31.9 +/- 0.9 degrees C). Venous blood was sampled before and after each session for measurement of serum osmolality and serum Hsp70. In addition, T (c), heart rate (HR) and power output (PO) was measured throughout the 90 min to ensure that heat acclimation was achieved during the 15-day period. The results show that the subject was successfully heat acclimated as seen by the lowered HR at rest and during exercise, decreased resting and exercising T (c) and an increased PO. The heat exercise resulted in an initial increase in Hsp70 concentrations, known as thermotolerance, and the increase in Hsp70 after exercise was inversely correlated to the resting values of Hsp70 (Spearman's rank correlation = -0.81, p < 0.01). Furthermore, the 15-day heat-exercise protocol also increased the basal levels of Hsp70, a response different from that of thermotolerance. This is, as far as we are aware, the first report showing Hsp70 levels during consecutive days of intermittent heat exposure giving rise to heat acclimation. In conclusion, a relatively longer heat acclimation protocol is suggested to obtain maximum benefit of heat acclimation inclusive of both cellular and systemic adaptations.

Purpose: The purpose of this work was to determine the effects of caffeine on high intensity time trial (TT) cycling performance in well-trained subjects., Subjects: Six male cyclists with the following physical characteristics (mean +/- SD) age 30.7 +/- 12, height 179.3 +/- 7.5 cm, mass 70.0 +/- 7.5 kg, VO2max 65.0 +/- 6.3 mL.kg-1.min-1 undertook three 1-h TT performances, control (C), placebo (P) and caffeine (CAF), on a Velotron cycle ergometer conducted in a double-blind, random fashion. Subjects rested for 60 min and were then given CAF or P in a dose of 6 mg.kg-1 body mass and then commenced exercise after another 60 min of rest. Before ingestion, 60 min postingestion, and at the end of the TT, finger-prick blood samples were analyzed for lactate., Results: The cyclists rode significantly further in the CAF trial (28.0 +/- 1.3 km) than they did in the C (26.3 +/- 1.5 km, P < .01) or P (26.4 +/- 1.5 km, P < .02) trials. No differences were seen in heart rate data throughout the TT (P > .05). Blood lactate levels were significantly higher at the end of the trials than either at rest or postingestion (P < .0001), but there were no differences between the three trial groups., Conclusion: On the basis of the data, we concluded that performance was improved with the use of a caffeine supplement.

The purpose of this study was to compare plasma markers of metabolic stress and other physiological parameters during prolonged endurance exercise of different intensity in trained subjects possessing a "high" or "low" lactate threshold (LT) expressed as a percentage (%) of peak power output (PPO). Fifteen trained male cyclists completed an incremental exercise test for determination of PPO and the LT (% PPO). Each subject then completed a 90-min and 20-min exercise trial at an intensity representing 75 and 85 % of PPO, respectively. Blood lactate (La), as well as plasma hypoxanthine (Hx) and uric acid (UA) were measured during each exercise trial. The responses in two groups, one (n = 8) with a LT approximately 65 % PPO (LT (low)), the other group (n = 7) with a LT approximately 75 % (LT (high)) (p < 0.01), were then compared. With the exception of UA, La and Hx increased significantly (p < 0.01) throughout each exercise trial compared to rest. However, there were no significant differences in each trial between the two groups of cyclists. There were also no significant differences in the other physiological parameters in each exercise trial between the subjects in LT (low) and LT (high). This study demonstrates that in trained cyclists homogeneous in terms of PPO, plasma markers of metabolic demand during prolonged exercise are not influenced by the LT when measured in an incremental exercise test.

Purpose: To determine the relationship between maximum workload (W(peak)), the workload at the onset of blood lactate accumulation (W(OBLA)), the lactate threshold (W(LTlog)) and the D(max) lactate threshold, and the average power output obtained during a 90-min (W(90-min)) and a 20-min (W(20-min)) time trial (TT) in a group of well-trained cyclists., Methods: Nine male cyclists (.VO(2max) 62.7 +/- 0.8 mL.kg(-1).min(-1)) who were competing regularly in triathlon or cycle TT were recruited for the study. Each cyclist performed four tests on an SRM isokinetic cycle ergometer over a 2-wk period. The tests comprised 1) a continuous incremental ramp test for determination of maximal oxygen uptake (.VO(2max) (L.min(-1) and mL.kg(-1).min(-1)); 2) a continuous incremental lactate test to measure W(peak), W(OBLA), W(LTlog), and the D(max) lactate threshold; and 3) a 20-min TT and 4) a 90-min TT, both to determine the average power output (in watts)., Results: The average power output during the 90-min TT (W(90-min)) was significantly (P < 0.01) correlated with W(peak) (r = 0.91), W(LTlog) (r = 0.91), and the D(max) lactate threshold (r = 0.77, P < 0.05). In contrast, W(20-min) was significantly (P < 0.05) related to .VO(2max) (L.min(-1)) (r = 0.69) and W(LTlog) (r = 0.67). The D(max) lactate threshold was not significantly correlated to W(20-min) (r = 0.45). Furthermore, W(OBLA) was not correlated to W(90-min) (r = 0.54) or W(20-min) (r = 0.23). In addition, .VO(2max) (mL.kg(-1).min(-1)) was not significantly related to W(90-min) (r = 0.11) or W(20-min) (r = 0.47)., Conclusion: The results of this study demonstrate that in subelite cyclists the relationship between maximum power output and the power output at the lactate threshold, obtained during an incremental exercise test, may change depending on the length of the TT that is completed.

The aim of this study was to determine the effects of different conditions of heat and humidity on two multiple bouts of high intensity cycling with 60 min recovery between each bout. Eight males (age: 25.5+/-1.8 yr, height: 179.0+/-3.7 cm; weight: 72.3+/-4.0 kg; VO2peak: 51.5+/-2.4 ml x kg(-1) x min(-1), Peak Aerobic Power: 366+/-13 W) volunteered for this study. After undertaking VO2peak testing, all participated randomly, in three consecutive 30 s Wingate tests in three different environmental conditions being: Normal (22 degrees C/30% RH), Wet (30 degrees C/85% RH), and Hot (40 degrees C/40% RH). Subjects were then monitored for the 60 min post-exercise period after which time they repeated the Wingate tests and were again monitored for 60 min. Blood samples were taken pre, immediately post exercise, and at 1, 5, 10, 15, 30, 45, and 60 min into each of the recovery periods and analysed for lactate, pH, and hematocrit. Heart rate was monitored continuously throughout exercise (5 s average) and recovery (60 s average). Weight was measured pre exercise and at 15, 30, 45, and 60 min post-exercise. Urine samples were collected at the same time and analysed for osmolality. The results of the experiment indicated that environmental conditions had no effect on the performance of either series 1 or 2 Wingate tests. Neither were there any changes in weight throughout the three conditions or across the condition. Post exercise pH levels were lower than pre exercise values (p < 0.0001) and the reverse was true for blood lactate levels (p < 0.0003). We conclude that anaerobic exercise is not unduly affected by hot or humid conditions when subjects can re-hydrate according to decreases in body weight.

The aim of this study was to determine whether a dose of 300-mg x kg(-1) body mass of sodium bicarbonate would effect a high-intensity, 1-h maximal cycle ergometer effort. Ten male, well-trained [maximum oxygen consumption 67.3 (3.3) ml x kg(-1) x min(-1), mean (SD)] volunteer cyclists acted as subjects. Each undertook either a control (C), placebo (P), or experimental (E) ride in a random, double-blind fashion on a modified, air-braked cycle ergometer, attached to a personal computer to which the work and power data was downloaded at 10 Hz. Fingertip blood was sampled at 10-min intervals throughout the exercise. Blood was also sampled at 1, 3, 5, and 10 min post-exercise. Blood was analysed for lactate, partial pressure of Carbon dioxide and oxygen, pH and plasma bicarbonate (HCO-) concentration. Randomly chosen pairs of subjects were asked to complete as much work as possible during the 60-min exercise periods in an openly competitive situation. The sodium bicarbonate had the desired effect of increasing blood HCO3- prior to the start of the test. The subjects in E completed 950.9 (81.1) kJ of work, which was significantly more (F(2,27) = 5.28, P < 0.01) than during either the C [835.5 (100.2) kJ] or P [839.0 (88.6) kJ] trials. No differences were seen in peak power or in the power:mass ratio between these three groups. The results of this study suggest that sodium bicarbonate may be used to offset the fatigue process during high-intensity, aerobic cycling lasting 60 min.

The aim of this research was to determine if circadian rhythms have an effect on time trial cycling performance of 15 min duration. Seven males (Mean+/-SD): age, 22.3+/-4.9 yr; height 179.0+/-7.9 cm, body mass 74.5+/-15.5 kg; VO2max 68.0+/-5.7 ml x kg(-1) x min(-1) who were all competitive cyclists or triathletes with previous experience in laboratory testing procedures volunteered to participate in this study. Each of the seven subjects underwent a series of four tests; one VO2 max test, and three 15 min maximal performance tests, at varying times during a 24 hr period. Testing times were at 08.00-10.00; 14.00-16.00 and 20.00-22.00 hours. Heart rate was recorded during the last 10-15 seconds of each minute and blood lactate levels were taken at 5 and 10 min during exercise and again immediately post-exercise. O2 consumption was measured continuously using open circuit spirometry. RPE was measured using the Borg scale at 5 and 10 min during, and again immediately following the completion of testing. Resting oral temperature was the only variable to show a significant time of day effect (p<0.05). Oral temperature during the afternoon was higher than both morning and evening results by 0.76 degrees C and 0.09 degrees C respectively. Total work (kJ) and average power output (W) were recorded at their highest during the morning session and reached a trough during the afternoon session, but these differences were not significant (p = 0.9997 and 0.9972 respectively). The results obtained in this study indicate that while certain biological rhythms are present, they appear to have no effect on this type of cycling performance. Although athletic performance may be enhanced by training programs that are compatible with an individuals body clock, the ability to perform and train at various times has an adaptive response which appears to over-ride these naturally inherent rhythms.

The aim of this experiment was to investigate the effects of differing pedalling speeds on the power-duration relationship during high intensity cycle ergometry with pedal cadences of 50 (low), 90 (intermediate) and 110 (high) r.min-1. This hyperbolic power-duration relationship can be described as: (P - phiPA).t = W', where P = power output, t = time to exhaustion, and phiPA and W' are constants. Eight volunteer male subjects, aged 24 +/- 2.6 yr, with no competitive cycling training took part in this study and each undertook thirteen tests on a Lode BV Excalibur Sport V1.52 cycle ergometer over an eight week period. The first exercise bout was a 30 W.min-1 incremental cycle at 50 r.min-1 to volitional fatigue. This allowed the identification of a range of power outputs that would be used to construct and examine the power-duration relationships for each subject at 50, 90 and 110 r.min-1. At both 50 and 90 r.min-1, power outputs of 30 W above and below and 60 W above the highest work rate, as well as the maximum work rate achieved during the incremental exercise test were chosen, while at 110 r.min-1, the power outputs chosen were 25 W above and below as well as 50 W above the highest work rate achieved during the incremental exercise test and also the maximum work rate achieved during the incremental exercise test were chosen. These four work rates for each pedalling frequency were chosen because they would have exercise times to exhaustion in the range of 1-10 minutes. Each exercise bout was preceded by four minutes of unloaded cycling and then the work rate was adjusted quickly to the desired load setting by the previously programmed computerised ergometer. The results of this work indicate that for the group of subjects studied, pedalling a cycle ergometer at 50 r.min-1 allows subjects to pedal for a significantly greater time than when pedalling at either 90 or 110 r.min-1. phiPA at 50 r.min-1 was significantly greater than when pedalling at either 90 (F(1,21) = 7.47, p < 0.01) or 110 r.min-1 (F(1,21) = 10.83, p < 0.0005). There was no significant (p > 0.22) difference between phiPA at 90 and 110 r.min-1, F(1,21) = 1.36. W' however, was not significantly different when the data for 50 r.min-1, 90 r.min-1 and 110 r.min-1 were compared (F50 r.min-1 (1,21) = 0.95; p > 0.41; F90 r.min-1(1,21) = 0.79, p > 0.53; F110 r.min-1 (1,21) = 0.78, p > 0.53). Our hypothesis, that endurance performance was reduced when recreational cyclists pedal at a high cadence when compared to a low cadence was correct. Maximum sustainable power output during cycle ergometry was higher at 50 r.min-1 than at either 90 or 110 r.min-1. At the intermediate cadence endurance was better than at the high but worse than at the low cadence. In conclusion, during endurance cycling, recreaional cyclists should pedal at lower rather than higher cadences.

Nine male recreational cyclist served as subjects in this experiment which included a control, placebo and caffeine trial. The aim of the experiment was to determine whether a 10 mg.kg-1 dose of caffeine given three hours prior to an incremental cycle ergometer exercise test, for caffeine naive subjects, would increase the time to exhaustion and therefore increase the amount of work undertaken by the cyclists. The cyclists initially worked at 100 watts for three minutes and then increased the workload by 50 watts every three minutes until exhaustion. Blood was drawn at the beginning of the test and every three minutes from an ante-cubital vein and was analysed for blood lactate, glucose and free fatty acids (FFA). Respiratory analysis was also undertaken and heart rate was monitored throughout the test. Subjects in the caffeine trial worked significantly longer and performed more work (p less than 0.05) than they did in either the control or placebo trials. FFA's were also significantly higher in this trial (p less than 0.05) and the lactate threshold was moved to the right as a percentage of the VO2max, which suggests less acidity and a decreased bicarbonate flushing. The respiratory exchange ratio data was significantly lowered (p less than 0.05) during workloads between 250 and 450 watts. No changes were seen in blood glucose or heart rates during the experiment. In conclusion, we feel that a 10 mg.kg-1 dose of caffeine is an ergogenic aid during incremental exercise when it is taken 3-4 hours prior to the exercise in fasting subjects who have diets low in caffeine.

It is known that an increased level of red blood cell 2,3-diphosphoglycerate (DPG) shifts the oxyhemoglobin dissociation curve to the right, thus allowing a greater unloading of oxygen at the tissue level. It has been hypothesized that phosphate might help increase VO2max by increasing 2,3-DPG level. Eight trained cyclists underwent three cycle ergometer tests (control, placebo, and experimental) to determine whether phosphate ingestion had any positive effect on VO2max, time to exhaustion, serum 2,3-DPG, and serum phosphate levels. We found no change between the control, placebo, or experimental conditions in pretest serum phosphate levels, but we did find increases in 2,3-DPG levels in the phosphate condition (p less than .05), which suggests that even a small amount of phosphate could increase levels of 2,3-DPG. We also found significant differences in VO2max between the control (p less than .05) and placebo (p less than .02) conditions and also in time to exhaustion between the three conditions (p less than .05). We suggest that phosphate may have an ergogenic effect, but clearly more work needs to be undertaken to ascertain the amount of phosphate required and the magnitude of the effect.

Short-course triathlons have recently become popular in Australia, especially with novice athletes as a lead up to the longer versions. This study investigated the changes that occurred in plasma volume of novice triathletes undertaking their first competitive triathlon. Ten males participated in the event which took place on a cool, overcast day and consisted of a 1.0-km swim, a 30-km cycle ride, and a 10-km run. The subjects were all well trained with VO2max values of 53.2 +/- 6.1 ml O2.kg-1.min-1. A control experiment was also conducted with the athletes spending the same time resting in the same position as they did while competing in the event. Blood was drawn and analyzed for hemoglobin and packed cell volume. The time for completion of the triathlon was 134.8 +/- 6.9 min, with the swim stage being 25.2 +/- 5.7 min, the cycle stage 60.9 +/- 7.1 min, and the running stage 48.7 +/- 6.6 min. Weight decreased significantly (P less than 0.01) during the event from a pre-event high of 71.7 +/- 7.9 kg to a post-event low of 70.3 +/- 7.6 kg. Plasma volume during the triathlon by 14.3% +/- 1.8% (P less than 0.001), but during the control trial by only 5.2% +/- 1.6%. The difference of 9.1% +/- 1.7% can be attributed to the effects of exercise on plasma volume rather than an effect of posture. The major decrease in plasma volume was during the running stage of the triathlon during which it decreased by 6.2% +/- 1.7%, of which 3.0% +/- 1.8% was attributable to exercise alone.(ABSTRACT TRUNCATED AT 250 WORDS)