Aerobic and anaerobic indices contributing to track endurance cycling performance

Can Hypoxia Alter the Anaerobic Capacity Measured by a Single Exhaustive Exercise?

The present study aimed to compare the MAODALT in situations of hypoxia and normoxia to confirm the method validity. Seventeen healthy and physically active men participated in this study, aged 25.2±3.2 years. All participants underwent four days of evaluation. The first day was performed a body composition test, an incremental test to exhaustion to determine the maximum oxygen uptake, familiarizing the hypoxia (H) and normoxia (N) situation and the equipment used. On the second, third and fourth days, supramaximal efforts were performed until exhaustion at 110% of maximum oxygen uptake, in a situation of hypoxia (FIO2=14.0%) and normoxia (FIO2=20.9%). The anaerobic capacity was considered the sum of energy supply of the alactic and lactic systens. The absolute or relative anaerobic capacity values were not different (H=3.9±1.1 L, N=3.8±0.9 L, p=0.69), similarly no differences were found for the alactic contribution (H=1.7±0.5 L, N=1.5±0.5 L, p=0.30) and lactic contribution (H=2.3±0.9 L, N=2.3±0.7 L, p=0.85). It can be concluded that the anaerobic capacity measured by a single exhaustive effort is not altered by hypoxia.

Power-duration relationship comparison in competition sprint cyclists from 1-s to 20-min. Sprint performance is more than just peak power

Current convention place peak power as the main determinant of sprint cycling performance. This study challenges that notion and compares two common durations of sprint cycling performance with not only peak power, but power out to 20-min. There is also a belief where maximal efforts of longer durations will be detrimental to sprint cycling performance. 56 data sets from 27 cyclists (21 male, 6 female) provided maximal power for durations from 1-s to 20-min. Peak power values are compared to assess the strength of correlation (R2), and any relationship (slope) across every level. R2 between 15-s- 30-s power and durations from 1-s to 20-min remained high (R2 ≥ 0.83). Despite current assumptions around 1-s power, our data shows this relationship is stronger around competition durations, and 1-s power also still shared strong relationships with longer durations out to 20-min. Slopes for relationships at shorter durations were closer to a 1:1 relationship than longer durations, but closer to long-duration slopes than to a 1:1 line. The present analyses contradicts both well-accepted hypotheses that peak power is the main driver of sprint cycling performance and that maximal efforts of longer durations out to 20-min will hinder sprint cycling. This study shows the importance and potential of training durations from 1-s to 20-min over a preparation period to improve competition sprint cycling performance.

Determination, measurement, and validation of maximal aerobic speed

This study determined Maximal Aerobic Speed (MAS) at a speed that utilizes maximal aerobic and minimal anaerobic contributions. This method of determining MAS was compared between endurance (ET) and sprint (ST) trained athletes. Nineteen and 21 healthy participants were selected for the determination and validation of MAS respectively. All athletes completed five exercise sessions in the laboratory. Participants validating MAS also ran an all-out 5000 m at the track. Oxygen uptake at MAS was at 96.09 ± 2.51% maximal oxygen consumption ([Formula: see text]). MAS had a significantly higher correlation with velocity at lactate threshold (vLT), critical speed, 5000 m, time-to-exhaustion velocity at delta 50 in addition to 5% velocity at [Formula: see text] (T_limυΔ50 + 5%v[Formula: see text]), and Vsub%95 (υΔ50 or υΔ50 + 5%v[Formula: see text]) compared with v[Formula: see text], and predicted 5000 m speed (R² = 0.90, p < 0.001) and vLT (R² = 0.96, p < 0.001). ET athletes achieved significantly higher MAS (16.07 ± 1.58 km·h^-1 vs. 12.77 ± 0.81 km·h^-1, p ≤ 0.001) and maximal aerobic energy (E_MAS) (52.87 ± 5.35 ml·kg^-1·min^-1 vs. 46.42 ± 3.38 ml·kg^-1·min^-1, p = 0.005) and significantly shorter duration at MAS (ET: 678.59 ± 165.44 s; ST: 840.28 ± 164.97 s, p = 0.039). ST athletes had significantly higher maximal speed (35.21 ± 1.90 km·h^-1, p < 0.001) at a significantly longer distance (41.05 ± 3.14 m, p = 0.003) in the 50 m sprint run test. Significant differences were also observed in 50 m sprint performance (p < 0.001), and peak post-exercise blood lactate (p = 0.005). This study demonstrates that MAS is more accurate at a percentage of v[Formula: see text] than at v[Formula: see text]. The accurate calculation of MAS can be used to predict running performances with lower errors (Running Energy Reserve Index Paper).

Effect of varying recovery intensities on power outputs during severe intensity intervals in trained cyclists during the Covid-19 pandemic

Purpose

The study aimed to investigate the effects of different recovery intensities on the power outputs of repeated severe intensity intervals and the implications for W' reconstitution in trained cyclists.

Methods

Eighteen trained cyclists (FTP 258.0 ± 42.7 W; weekly training 8.6 ± 1.7 h∙week-1) familiar with interval training, use of the Zwift® platform throughout the Covid-19 pandemic, and previously established FTP (95% of mean power output from a 20-min test), performed 5 × 3-min severe intensity efforts interspersed with 2-min recoveries. Recovery intensities were: 50 W (LOW), 50% of functional threshold power (MOD), and self-selected power output (SELF).

Results

Whilst power outputs declined as the session progressed, mean power outputs during the severe intervals across the conditions were not different to each other (LOW 300.1 ± 48.1 W; MOD: 296.9 ± 50.4 W; SELF: 298.8 ± 53.3 W) despite the different recovery conditions. Mean power outputs of the self-selected recovery periods were 121.7 ± 26.2 W. However, intensity varied during the self-selected recovery periods, with values in the last 15 s being greater than the first 15 s (p < 0.001) and decreasing throughout the session (128.7 ± 25.4 W to 113.9 ± 29.3 W).

Conclusion

Reducing recovery intensities below 50% of FTP failed to enhance subsequent severe intensity intervals, suggesting that a lower limit for optimal W' reconstitution had been reached. As self-selected recoveries were seen to adapt to maintain the severe intensity power output as the session progressed, adopting such a strategy might be preferential for interval training sessions.

Critical Power, Work Capacity, and Recovery Characteristics of Team-Pursuit Cyclists

PURPOSE

Leading a 4-km team pursuit (TP) requires high-intensity efforts above critical power (CP) that deplete riders' finite work capacity (W'), whereas riders following in the aerodynamic draft may experience some recovery due to reduced power demands. This study aimed to determine how rider ability and CP and W' measures impact TP performance and the extent to which W' can reconstitute during recovery positions in a TP race.

METHODS

Three TP teams, each consisting of 4 males, completed individual performance tests to determine their CP and W'. Teams were classified based on their performance level as international (INT), national (NAT), or regional (REG). Each team performed a TP on an indoor velodrome (INT: 3:49.9; NAT: 3:56.7; and REG: 4:05.4; min:s). Ergometer-based TP simulations with an open-ended interval to exhaustion were performed to measure individual ability to reconstitute W' at 25 to 100 W below CP.

RESULTS

The INT team possessed higher CP (407 [4] W) than both NAT (381 [13] W) and REG (376 [15] W) (P < .05), whereas W' was similar between teams (INT: 27.2 [2.8] kJ; NAT: 29.3 [2.4] kJ; and REG: 28.8 [1.6] kJ; P > .05). The INT team expended 104% (5%) of their initial W' during the TP and possessed faster rates of recovery than NAT and REG at 25 and 50 W below CP (P < .05).

CONCLUSIONS

The CP and rate of W' reconstitution have a greater impact on TP performance than W' magnitude and can differentiate TP performance level.

Testing, Training, and Optimising Performance of Track Cyclists: A Systematic Mapping Review

Background

Track cyclists must develop mental, physical, tactical and technical capabilities to achieve success at an elite level. Given the importance of these components in determining performance, it is of interest to understand the volume of evidence to support implementation in practice by coaches, practitioners, and athletes.

Objective

The aim of this study was to conduct a systematic mapping review to describe the current scale and density of research for testing, training and optimising performance in track cycling.

Methods

All publications involving track cyclist participants were reviewed from four databases (PubMed, SPORTDiscus, Academic Search Complete, Cochrane Library) plus additional sources. Search results returned 4019 records, of which 71 met the inclusion criteria for the review.

Results

The review revealed most published track cycling research investigated athlete testing followed by performance optimisation, with training being the least addressed domain. Research on the physical components of track cycling has been published far more frequently than for tactical or technical components, and only one study was published on the mental components of track cycling. No true experimental research using track cyclists has been published, with 51 non-experimental and 20 quasi-experimental study designs.

Conclusions

Research in track cycling has been growing steadily. However, it is evident there is a clear preference toward understanding the physical—rather than mental, tactical, or technical—demands of track cycling. Future research should investigate how this aligns with coach, practitioner, and athlete needs for achieving track cycling success.

Registration

This systematic mapping review was registered on the Open Science Framework (osf.io/wt7eq).

Supplementary Information

The online version contains supplementary material available at 10.1007/s40279-021-01565-z.

The Importance of 'Durability' in the Physiological Profiling of Endurance Athletes

Profiling physiological attributes is an important role for applied exercise physiologists working with endurance athletes. These attributes are typically assessed in well-rested athletes. However, as has been demonstrated in the literature and supported by field data presented here, the attributes measured during routine physiological-profiling assessments are not static, but change over time during prolonged exercise. If not accounted for, shifts in these physiological attributes during prolonged exercise have implications for the accuracy of their use in intensity regulation during prolonged training sessions or competitions, quantifying training adaptations, training-load programming and monitoring, and the prediction of exercise performance. In this review, we argue that current models used in the routine physiological profiling of endurance athletes do not account for these shifts. Therefore, applied exercise physiologists working with endurance athletes would benefit from development of physiological-profiling models that account for shifts in physiological-profiling variables during prolonged exercise and quantify the 'durability' of individual athletes, here defined as the time of onset and magnitude of deterioration in physiological-profiling characteristics over time during prolonged exercise. We propose directions for future research and applied practice that may enable better understanding of athlete durability.

Muscle Typology of World-Class Cyclists across Various Disciplines and Events

PURPOSE

Classic track-and-field studies demonstrated that elite endurance athletes exhibit a slow muscle typology, whereas elite sprint athletes have a predominant fast muscle typology. In elite cycling, conclusive data on muscle typology are scarce, which may be due to the invasive nature of muscle biopsies. The noninvasive estimation of muscle typology through the measurement of muscle carnosine enabled to explore the muscle typology of 80 world-class cyclists of different disciplines.

METHODS

The muscle carnosine content of 80 cyclists (4 bicycle motor cross racing [BMX], 33 track, 8 cyclo-cross, 24 road, and 11 mountain bike) was measured in the soleus and gastrocnemius by proton magnetic resonance spectroscopy and expressed as a z-score relative to a reference population. Track cyclists were divided into track sprint and endurance cyclists based on their Union Cycliste Internationale (UCI) ranking. Moreover, road cyclists were further characterized based on the percentage of UCI points earned during either single and multistage races.

RESULTS

BMX cyclists (carnosine aggregate z-score of 1.33) are characterized by a faster muscle typology than track, cyclo-cross, road, and mountain bike cyclists (carnosine aggregate z-score of -0.08, -0.76, -0.96, and -1.02, respectively; P < 0.05). Track cyclists also possess a faster muscle typology compared with mountain bikers (P = 0.033) and road cyclists (P = 0.005). Moreover, track sprinters show a significant faster muscle typology (carnosine aggregate z-score of 0.87) compared with track endurance cyclists (carnosine aggregate z-score of -0.44) (P < 0.001). In road cyclists, the higher the carnosine aggregate z-score, the higher the percentage of UCI points gained during single-stage races (r = 0.517, P = 0.010).

CONCLUSIONS

Prominent differences in the noninvasively determined muscle typology exist between elite cyclists of various disciplines, which opens opportunities for application in talent orientation and transfer.

Validity of dynamical analysis to characterize heart rate and oxygen consumption during effort tests

Performance is usually assessed by simple indices stemming from cardiac and respiratory data measured during graded exercise test. The goal of this study is to characterize the indices produced by a dynamical analysis of HR and VO₂ for different effort test protocols, and to estimate the construct validity of these new dynamical indices by testing their links with their standard counterparts. Therefore, two groups of 32 and 14 athletes from two different cohorts performed two different graded exercise testing before and after a period of training or deconditioning. Heart rate (HR) and oxygen consumption (VO₂) were measured. The new dynamical indices were the value without effort, the characteristic time and the amplitude (gain) of the HR and VO₂ response to the effort. The gain of HR was moderately to strongly associated with other performance indices, while the gain for VO₂ increased with training and decreased with deconditioning with an effect size slightly higher than VO₂ max. Dynamical analysis performed on the first 2/3 of the effort tests showed similar patterns than the analysis of the entire effort tests, which could be useful to assess individuals who cannot perform full effort tests. In conclusion, the dynamical analysis of HR and VO₂ obtained during effort test, especially through the estimation of the gain, provides a good characterization of physical performance, robust to less stringent effort test conditions.

Maximal lactate accumulation rate and post-exercise lactate kinetics in handcycling and cycling

The aim of this study was to assess lactate kinetics, maximal lactate accumulation rate (⩒La_max) and peak power output (PO_max) in a 15-s all-out exercise in handcycling (HC) and cycling (C) in terms of (1) reliability, (2) differences and (3) correlations between HC and C. Eighteen female and male competitive triathletes performed two trials (separated by one week) of a 15-s all-out sprint test in HC and C. Tests were performed in a recumbent racing handcycle and on the participants' own road bike that were attached to an ergometer. Reliability was assessed using intraclass correlation coefficient (ICC). PO_max and ⩒La_max demonstrated high reliability in HC (ICC = 0.972, ICC = 0.828) and C (ICC = 0.937, ICC = 0.872). PO_max (d = -2.54, P < 0.0005) and ⩒La_max (d = -1.62, P < 0.0005) were lower in HC compared to C. PO_max and ⩒La_max correlated in HC (r = 0.729, P = 0.001) and C (r = 0.710, P = 0.001). There was no significant correlation between HC and C in PO_max (r = 0.442, P = 0.066) and ⩒La_max (r = 0.455, P = 0.058). Whereas the exchange velocity of lactate (k₁) was similar in HC and C, the removal velocity (k₂) was significantly higher in HC. ⩒La_max and PO_max during sprint exercise are highly reliable and demonstrate a correlation in both HC and C. However, since ⩒La_max and PO_max are significantly higher in C and not correlated between HC and C, ⩒La_max and PO_max seem to be extremity-specific.

Qualitative Video Analysis of Track-Cycling Team Pursuit in World-Class Athletes

Context: Track-cycling team pursuit (TP) is a highly technical effort involving 4 athletes completing 4 km from a standing start, often in less than 240 s. Transitions between athletes leading the team are obviously of utmost importance. Purpose: To perform qualitative video analyses of transitions of world-class athletes in TP competitions. Methods: Videos captured at 100 Hz were recorded for 77 races (including 96 different athletes) in 5 international track-cycling competitions (eg, UCI World Cups and World Championships) and analyzed for the 12 best teams in the UCI Track Cycling TP Olympic ranking. During TP, 1013 transitions were evaluated individually to extract quantitative (eg, average lead time, transition number, length, duration, height in the curve) and qualitative (quality of transition start, quality of return at the back of the team, distance between third and returning rider score) variables. Determination of correlation coefficients between extracted variables and end time allowed assessment of relationships between variables and relevance of the video analyses. Results: Overall quality of transitions and end time were significantly correlated (r = .35, P = .002). Similarly, transition distance (r = .26, P = .02) and duration (r = .35, P = .002) were positively correlated with end time. Conversely, no relationship was observed between transition number, average lead time, or height reached in the curve and end time. Conclusion: Video analysis of TP races highlights the importance of quality transitions between riders, with preferably swift and short relays rather than longer lead times for faster race times.

Metabolic consequences of β-alanine supplementation during exhaustive supramaximal cycling and 4000-m time-trial performance

The present study investigated the effects of β-alanine supplementation on the resultant blood acidosis, lactate accumulation, and energy provision during supramaximal-intensity cycling, as well as the aerobic and anaerobic contribution to power output during a 4000-m cycling time trial (TT). Seventeen trained cyclists (maximal oxygen uptake = 4.47 ± 0.55 L·min(-1)) were administered 6.4 g of β-alanine (n = 9) or placebo (n = 8) daily for 4 weeks. Participants performed a supramaximal cycling test to exhaustion (equivalent to 120% maximal oxygen uptake) before (PreExh) and after (PostExh) the 4-week supplementation period, as well as an additional postsupplementation supramaximal cycling test identical in duration and power output to PreExh (PostMatch). Anaerobic capacity was quantified and blood pH, lactate, and bicarbonate concentrations were measured pre-, immediately post-, and 5 min postexercise. Subjects also performed a 4000-m cycling TT before and after supplementation while the aerobic and anaerobic contributions to power output were quantified. β-Alanine supplementation increased time to exhaustion (+12.8 ± 8.2 s; P = 0.041) and anaerobic capacity (+1.1 ± 0.7 kJ; P = 0.048) in PostExh compared with PreExh. Performance time in the 4000-m TT was reduced following β-alanine supplementation (-6.3 ± 4.6 s; P = 0.034) and the mean anaerobic power output was likely to be greater (+6.2 ± 4.5 W; P = 0.035). β-Alanine supplementation increased time to exhaustion concomitant with an augmented anaerobic capacity during supramaximal intensity cycling, which was also mirrored by a meaningful increase in the anaerobic contribution to power output during a 4000-m cycling TT, resulting in an enhanced overall performance.

Prediction of rowing ergometer performance from functional anaerobic power, strength and anthropometric components

The aim of this research was to develop different regression models to predict 2000 m rowing ergometer performance with the use of anthropometric, anaerobic and strength variables and to determine how precisely the prediction models constituted by different variables predict performance, when conducted together in the same equation or individually. 38 male collegiate rowers (20.17 ± 1.22 years) participated in this study. Anthropometric, strength, 2000 m maximal rowing ergometer and rowing anaerobic power tests were applied. Multiple linear regression procedures were employed in SPSS 16 to constitute five different regression formulas using a different group of variables. The reliability of the regression models was expressed by R2 and the standard error of estimate (SEE). Relationships of all parameters with performance were investigated through Pearson correlation coefficients. The prediction model using a combination of anaerobic, strength and anthropometric variables was found to be the most reliable equation to predict 2000 m rowing ergometer performance (R2 = 0.92, SEE= 3.11 s). Besides, the equation that used rowing anaerobic and strength test results also provided a reliable prediction (R2 = 0.85, SEE= 4.27 s). As a conclusion, it seems clear that physiological determinants which are affected by anaerobic energy pathways should also get involved in the processes and models used for performance prediction and talent identification in rowing.

Caffeine alters anaerobic distribution and pacing during a 4000-m cycling time trial

The purpose of the present study was to investigate the effects of caffeine ingestion on pacing strategy and energy expenditure during a 4000-m cycling time-trial (TT). Eight recreationally-trained male cyclists volunteered and performed a maximal incremental test and a familiarization test on their first and second visits, respectively. On the third and fourth visits, the participants performed a 4000-m cycling TT after ingesting capsules containing either caffeine (5 mg.kg⁻¹ of body weight, CAF) or cellulose (PLA). The tests were applied in a double-blind, randomized, repeated-measures, cross-over design. When compared to PLA, CAF ingestion increased mean power output [219.1±18.6 vs. 232.8±21.4 W; effect size (ES)  = 0.60 (95% CI = 0.05 to 1.16), p = 0.034] and reduced the total time [419±13 vs. 409±12 s; ES = −0.71 (95% CI = −0.09 to −1.13), p = 0.026]. Furthermore, anaerobic contribution during the 2200-, 2400-, and 2600-m intervals was significantly greater in CAF than in PLA (p<0.05). However, the mean anaerobic [64.9±20.1 vs. 57.3±17.5 W] and aerobic [167.9±4.3 vs. 161.8±11.2 W] contributions were similar between conditions (p>0.05). Similarly, there were no significant differences between CAF and PLA for anaerobic work (26363±7361 vs. 23888±6795 J), aerobic work (68709±2118 vs. 67739±3912 J), or total work (95245±8593 vs. 91789±7709 J), respectively. There was no difference for integrated electromyography, blood lactate concentration, heart rate, and ratings of perceived exertion between the conditions. These results suggest that caffeine increases the anaerobic contribution in the middle of the time trial, resulting in enhanced overall performance.

Caffeine increases anaerobic work and restores cycling performance following a protocol designed to lower endogenous carbohydrate availability

The purpose this study was to examine the effects of caffeine ingestion on performance and energy expenditure (anaerobic and aerobic contribution) during a 4-km cycling time trial (TT) performed after a carbohydrate (CHO) availability-lowering exercise protocol. After preliminary and familiarization trials, seven amateur cyclists performed three 4-km cycling TT in a double-blind, randomized and crossover design. The trials were performed either after no previous exercise (CON), or after a CHO availability-lowering exercise protocol (DEP) performed in the previous evening, followed by either placebo (DEP-PLA) or 5 mg.kg(-1) of caffeine intake (DEP-CAF) 1 hour before the trial. Performance was reduced (-2.1%) in DEP-PLA vs CON (421.0±12.3 vs 412.4±9.7 s). However, performance was restored in DEP-CAF (404.6±17.1 s) compared with DEP-PLA, while no differences were found between DEP-CAF and CON. The anaerobic contribution was increased in DEP-CAF compared with both DEP-PLA and CON (67.4±14.91, 47. 3±14.6 and 55.3±14.0 W, respectively), and this was more pronounced in the first 3 km of the trial. Similarly, total anaerobic work was higher in DEP-CAF than in the other conditions. The integrated electromyographic activity, plasma lactate concentration, oxygen uptake, aerobic contribution and total aerobic work were not different between the conditions. The reduction in performance associated with low CHO availability is reversed with caffeine ingestion due to a higher anaerobic contribution, suggesting that caffeine could access an anaerobic "reserve" that is not used under normal conditions.

Isoperformance curves: an application in team selection

An isoperformance curve (or surface) defines combinations of two (or more) physiological attributes of individuals such that equal performances for a specified event would be expected of them. Parameters from the two- and three-parameter critical power models are used to illustrate the concept. There are a number of sporting races where teams of individuals compete simultaneously as a unit. Rowing and team pursuit cycling are two well-known examples. Team selection may be difficult if there are more candidates available than places in the team. Based on the assumption that team members should be evenly matched with respect to performance rather than physiological attributes, proximity to a particular isoperformance curve (or surface) may suggest an obvious grouping of individuals. Isoperformance lines also enable identification of an athlete's individual training needs, since the components of the isoperformance lines can be affected by specific training interventions.

Effects of starting strategy on 5-min cycling time-trial performance

The importance of pacing for middle-distance performance is well recognized, yet previous research has produced equivocal results. Twenty-six trained male cyclists (VO2 peak 62.8 +/- 5.9 ml x kg(-1) x min(-1); maximal aerobic power output 340 +/- 43 W; mean +/- s) performed three cycling time-trials where the total external work (102.7 +/- 13.7 kJ) for each trial was identical to the best of two 5-min habituation trials. Markers of aerobic and anaerobic metabolism were assessed in 12 participants. Power output during the first quarter of the time-trials was fixed to control external mechanical work done (25.7 +/- 3.4 kJ) and induce fast-, even-, and slow-starting strategies (60, 75, and 90 s, respectively). Finishing times for the fast-start time-trial (4:53 +/- 0:11 min:s) were shorter than for the even-start (5:04 +/- 0:11 min:s; 95% CI = 5 to 18 s, effect size = 0.65, P < 0.001) and slow-start time-trial (5:09 +/- 0:11 min:s; 95% CI = 7 to 24 s, effect size = 1.00, P < 0.001). Mean VO2 during the fast-start trials (4.31 +/- 0.51 litres x min(-1)) was 0.18 +/- 0.19 litres x min(-1) (95% CI = 0.07 to 0.30 litres x min(-1), effect size = 0.94, P = 0.003) higher than the even- and 0.18 +/- 0.20 litres x min(-1) (95% CI = 0.5 to 0.30 litres x min(-1), effect size = 0.86, P = 0.007) higher than the slow-start time-trial. Oxygen deficit was greatest during the first quarter of the fast-start trial but was lower than the even- and slow-start trials during the second quarter of the trial. Blood lactate and pH were similar between the three trials. In conclusion, performance during a 5-min cycling time-trial was improved with the adoption of a fast- rather than an even- or slow-starting strategy.

Procedures for monitoring recombinant erythropoietin and analogs in doping

Hemoglobin concentration is one of the principal factors of aerobic power and, consequently, of performance in many types of physical activities. The use of recombinant human erythropoietin is, therefore, particularly powerful for improving the physical performances of patients, and, more generally, improving their quality of life. This article discusses procedures for monitoring recombinant erythropoietin and its analogues in doping for athletic performance.

Longitudinal changes in haemoglobin mass and VO(2max) in adolescents

This study assessed the relationship between haemoglobin mass (Hb(mass)) and maximum oxygen consumption (VO(2max)) in adolescents over 1 year. Twenty-three subjects (11-15 years) participated; 12 undertook ~12 months of cycle training (cyclists) and 11 were sedentary (controls). Hb(mass) and VO(2max) were measured approximately every 3 months. At baseline there was a high correlation (r = 0.82, P < 0.0001) between relative VO(2max) (ml kg(-1) min(-1)) and relative Hb(mass) (g kg(-1)). During 12 months there was a significant increase in relative VO(2max) of the cyclists but not the controls; however, there was no corresponding increase in relative Hb(mass) of either group. The correlation between percent changes in relative VO(2max) and relative Hb(mass) was not significant for cyclists (r = 0.31, P = 0.33) or controls (r = 0.42, P = 0.19). Training does not increase relative Hb(mass) in adolescents consistent with a strong hereditary role for Hb(mass) and VO(2max). Hb(mass) may be used to identify adolescents who have a high VO(2max).

Comparison of different theoretical models estimating peak power output and maximal oxygen uptake in trained and elite triathletes and endurance cyclists in the velodrome

The aim of this study was to assess which of the equations that estimate peak power output and maximal oxygen uptake (VO2max) in the velodrome adapt best to the measurements made by reference systems. Thirty-four endurance cyclists and triathletes performed one incremental test in the laboratory and two tests in the velodrome. Maximal oxygen uptake and peak power output were measured with an indirect calorimetry system in the laboratory and with the SRM training system in the velodrome. The peak power output and VO2max of the field test were estimated by means of different equations. The agreement between the estimated and the reference values was assessed with the Bland-Altman method. The equation of Olds et al. (1995) showed the best agreement with respect to the peak power output reference values, and that of McCole et al. (1990) was the only equation to show good agreement with respect to the VO2max reference values. The VO2max values showed a higher coefficient of determination with respect to maximal aerobic speed when they were expressed in relative terms. In conclusion, the equations of Olds et al. (1995) and McCole et al. (1990) were best at estimating peak power output and VO2max in the velodrome, respectively.

The effect of acute simulated moderate altitude on power, performance and pacing strategies in well-trained cyclists

Athletes regularly compete at 2,000-3,000 m altitude where peak oxygen consumption (VO2peak) declines approximately 10-20%. Factors other than VO2peak including gross efficiency (GE), power output, and pacing are all important for cycling performance. It is therefore imperative to understand how all these factors and not just VO2peak are affected by acute hypobaric hypoxia to select athletes who can compete successfully at these altitudes. Ten well-trained, non-altitude-acclimatised male cyclists and triathletes completed cycling tests at four simulated altitudes (200, 1,200, 2,200, 3,200 m) in a randomised, counter-balanced order. The exercise protocol comprised 5 x 5-min submaximal efforts (50, 100, 150, 200 and 250 W) to determine submaximal VO2 and GE and, after 10-min rest, a 5-min maximal time-trial (5-minTT) to determine VO2peak and mean power output (5-minTT(power)). VO2peak declined 8.2 +/- 2.0, 13.9 +/- 2.9 and 22.5 +/- 3.8% at 1,200, 2,200 and 3,200 m compared with 200 m, respectively, P < 0.05. The corresponding decreases in 5-minTT(power) were 5.8 +/- 2.9, 10.3 +/- 4.3 and 19.8 +/- 3.5% (P < 0.05). GE during the 5-minTT was not different across the four altitudes. There was no change in submaximal VO2 at any of the simulated altitudes, however, submaximal efficiency decreased at 3,200 m compared with both 200 and 1,200 m. Despite substantially reduced power at simulated altitude, there was no difference in pacing at the four altitudes for athletes whose first trial was at 200 or 1,200 m; whereas athletes whose first trial was at 2,200 or 3,200 m tended to mis-pace that effort. In conclusion, during the 5-minTT there was a dose-response effect of hypoxia on both VO2peak and 5-minTT(power) but no effect on GE.

Success in elite cycling: A prospective and retrospective analysis of race results

The development of peak performances is a main research focus in sports science. It is unclear how many former top junior athletes achieve success in the elite class later. The aim of the present study was to examine the careers of athletes who participated in major junior or adult/elite cycling events using prospective and retrospective analysis of competition results. The official results of major junior (age < or = 18 years) and elite (age > 18 years) cycling races from 1980 to 2004 were analysed. Age-related aspects, career lengths, and success were compared between riders who presented results in both junior and elite races (JUNIOR ELITE) and riders who had no junior race results (ELITE ONLY). Altogether, 27,454 results of 8004 athletes from 108 countries were collected. We found that 29.4% of the elite athletes had participated in junior World Championships, and that 34% of the participants in junior World Championships later participated in major elite competitions. JUNIOR ELITE athletes are significantly more successful in several cycling disciplines and have their first and last elite result at a younger age than ELITE ONLY athletes. No difference was found in career lengths. The data presented here emphasize the importance of long-term training programmes in the development of peak performance in cycling.

The use of an eccentric chainring during an outdoor 1 km all-out cycling test

This study assessed whether an eccentric chainring that increases crank arm length at the downstroke and decreases it during the upstroke improves performance in a track cycling event: the 1000m time trial. It also determined whether selected physical and physiological variables and the velocity profile are associated with eccentric chainring performance. Twelve cyclists performed an outdoor 1000m time trial on a 333m banked, cement-surfaced track using two different chainrings, round and eccentric, in randomised order. The important findings of this study were that (1) performance did not significantly differ between chainrings; (2) neither the physiological variables (lactate and heart rate) nor the velocity profile (lap times) were affected by use of the eccentric design; (3) when time was saved with the eccentric chainring, it was significantly correlated with estimated lower limb muscle volume (r=-0.605), circumference (r=-0.739), estimated calf muscle volume (r=-0.772) and cross-sectional area (r=-0.745). Moreover, estimated lower limb muscle volume (r=-0.703), estimated calf muscle volume (r=-0.772) and cross-sectional area (r=-0.871) significantly predicted performance with the eccentric chainring. The physical variables associated with eccentric chainring performance were muscle anthropometric parameters. We have interpreted our results cautiously and suggest that the subjects who had greater lower limb muscle volume and greater calf muscle volume, seem to have had a significant advantage in performing with the eccentric chainring. Further testing with track specialists performing at national or international level would be helpful to define the maximal possibilities of this chainring.

Achievement of peak VO2 during a 90-s maximal intensity cycle sprint in adolescents

The aim of this study was to determine whether peak oxygen uptake (PVO2) attained in a 90-s maximal intensity cycle sprint is comparable to that from a conventional ramp test. Sixteen participants (13 boys and 3 girls, 14.6 +/- 0.4 yr) volunteered for the study. On Day 1 they completed a PVO2 test to exhaustion using a 25 W x min(-1) ramp protocol beginning at 50 W. Peak VO2 was defined as the highest VO2 value achieved, and aerobic power (Wmax) as the power output of the final 30 s. On Day 2 the participants completed two 90-s maximal sprints (S1 and S2). A 45-min recovery period separated each sprint. Mean oxygen uptake over the last 10 s of each sprint was determined as PVO2, and minimum power (MinP-30 s) as the mechanical power attained in the final 30 s. A one-way ANOVA was used to analyse differences between S1, S2, and the ramp test for PVO2 and MinP-30 s. Peak VO2 was not significantly different between the ramp, S1, or S2 (2.64 +/- 0.5, 2.49 +/- 0.5, and 2.53 +/- 0.5 L x min(-1), respectively, p > 0.68). The S1 and S2 PVO2 scores represented 91 +/- 10% and 92 +/- 10% of the ramp aerobic test. The MinP-30 s for S1 and S2 were significantly lower than the Wmax of the ramp test, p < 0.05. Hence, for researchers solely interested in PVO2 values, a shorter but more intensive protocol provides an alternative method to the traditional ramp aerobic test.

A comparison of two methods for the calculation of accumulated oxygen deficit

The aim of this study was to compare accumulated oxygen deficit data derived using two different exercise protocols with the aim of producing a less time-consuming test specifically for use with athletes. Six road and four track male endurance cyclists performed two series of cycle ergometer tests. The first series involved five 10 min sub-maximal cycle exercise bouts, a VO2peak test and a 115% VO2peak test. Data from these tests were used to estimate the accumulated oxygen deficit according to the calculations of Medbø et al. (1988). In the second series of tests, participants performed a 15 min incremental cycle ergometer test followed, 2 min later, by a 2 min variable resistance test in which they completed as much work as possible while pedalling at a constant rate. Analysis revealed that the accumulated oxygen deficit calculated from the first series of tests was higher (P < 0.02) than that calculated from the second series: 52.3 +/- 11.7 and 43.9 +/- 6.4 ml x kg(-1), respectively (mean +/- s). Other significant differences between the two protocols were observed for VO2peak, total work and maximal heart rate; all were higher during the modified protocol (P < 0.01 and P < 0.02, respectively). Oxygen kinetics were also significantly faster during the modified 2 min maximal test. We conclude that the difference in accumulated oxygen deficit between protocols was probably due to a reduced oxygen uptake, possibly caused by a slower oxygen on-response during the 115% VO2peak test in the first series, and VO2-power output regression differences caused by an elevated VO2 during the early stages of the second series.

The 4000-m team pursuit cycling world record: theoretical and practical aspects

Due to constant competition conditions, track cycling can be accurately modeled through physiological and biomechanical means. Mathematical modeling predicts an average workload of 520 W for every team member for a new team pursuit world record. Performance in team pursuit racing is highly dependent on aerobic capacity, anaerobic skills, and aerodynamic factors. The training concept of the 2000 record-breaking team pursuit team was based on unspecific training of these qualities and periodical, short-term recall of previously acquired track specific skills. Aerobic performance was trained through high overall training mileage (29,000-35,000 km.yr-1) with workload peaks during road stage races. Before major track events, anaerobic performance, and track-specific technical and motor skills were improved through discipline-specific track training. Training intensities were monitored through heart rate and lactate field tests during defined track-training bouts, based on previously performed laboratory exercise tests. During pursuit competition, analysis of half-lap split times allowed an estimation of the individual contribution of each rider to the team's performance and thereby facilitated modifications in team composition to optimize race speed. The theoretically predicted performance necessary for a new world record was achieved through careful planning of training and competition schedules based on a concise theoretical concept and the high physiological capacities of the participating athletes.

The effect of altitude on cycling performance: a challenge to traditional concepts

Acute exposure to moderate altitude is likely to enhance cycling performance on flat terrain because the benefit of reduced aerodynamic drag outweighs the decrease in maximum aerobic power [maximal oxygen uptake (VO2max)]. In contrast, when the course is mountainous, cycling performance will be reduced at moderate altitude. Living and training at altitude, or living in an hypoxic environment (approximately 2500 m) but training near sea level, are popular practices among elite cyclists seeking enhanced performance at sea level. In an attempt to confirm or refute the efficacy of these practices, we reviewed studies conducted on highly-trained athletes and, where possible, on elite cyclists. To ensure relevance of the information to the conditions likely to be encountered by cyclists, we concentrated our literature survey on studies that have used 2- to 4-week exposures to moderate altitude (1500 to 3000 m). With acclimatisation there is strong evidence of decreased production or increased clearance of lactate in the muscle, moderate evidence of enhanced muscle buffering capacity (beta m) and tenuous evidence of improved mechanical efficiency (ME) of cycling. Our analysis of the relevant literature indicates that, in contrast to the existing paradigm, adaptation to natural or simulated moderate altitude does not stimulate red cell production sufficiently to increase red cell volume (RCV) and haemoglobin mass (Hb(mass)). Hypoxia does increase serum erthyropoietin levels but the next step in the erythropoietic cascade is not clearly established; there is only weak evidence of an increase in young red blood cells (reticulocytes). Moreover, the collective evidence from studies of highly-trained athletes indicates that adaptation to hypoxia is unlikely to enhance sea level VO2max. Such enhancement would be expected if RCV and Hb(mass) were elevated. The accumulated results of 5 different research groups that have used controlled study designs indicate that continuous living and training at moderate altitude does not improve sea level performance of high level athletes. However, recent studies from 3 independent laboratories have consistently shown small improvements after living in hypoxia and training near sea level. While other research groups have attributed the improved performance to increased RCV and VO2max, we cite evidence that changes at the muscle level (beta m and ME) could be the fundamental mechanism. While living at altitude but training near sea level may be optimal for enhancing the performance of competitive cyclists, much further research is required to confirm its benefit. If this benefit does exist, it probably varies between individuals and averages little more than 1%.

Modelling human locomotion: applications to cycling

Mathematical models of performance in locomotor sports are reducible to functions of the sort y = f(x) where y is some performance variable, such as time, distance or speed, and x is a combination of predictor variables which may include expressions for power (or energy) supply and/or demand. The most valid and useful models are first-principles models that equate expressions for power supply and power demand. Power demand in cycling is the sum of the power required to overcome air resistance and rolling resistance, the power required to change the kinetic energy of the system, and the power required to ride up or down a grade. Power supply is drawn from aerobic and anaerobic sources, and modellers must consider not only the rate but also the kinetics and pattern of power supply. The relative contributions of air resistance to total demand, and of aerobic energy to total supply, increase curvilinearly with performance time, while the importance of other factors decreases. Factors such as crosswinds, aerodynamic accessories and drafting can modify the power demand in cycling, while body configuration/orientation and altitude will affect both power demand and power supply, often in opposite directions. Mathematical models have been used to solve specific problems in cycling, such as the chance of success of a breakaway, the optimal altitude for performance, creating a 'level playing field' to compare performances for selection purposes, and to quantify, in the common currency of minutes and seconds, the effects on performance of changes in physiological, environmental and equipment variables. The development of crank dynamometers and portable gas-analysis systems, combined with a modelling approach, will in the future provide valuable information on the effect of changes in equipment, configuration and environment on both supply and demand-side variables.

Characteristics of track cycling

Track cycling events range from a 200 m flying sprint (lasting 10 to 11 seconds) to the 50 km points race (lasting approximately 1 hour). Unlike road cycling competitions where most racing is undertaken at submaximal power outputs, the shorter track events require the cyclist to tax maximally both the aerobic and anaerobic (oxygen independent) metabolic pathways. Elite track cyclists possess key physical and physiological attributes which are matched to the specific requirements of their events: these cyclists must have the appropriate genetic predisposition which is then maximised through effective training interventions. With advances in technology it is now possible to accurately measure both power supply and demand variables under competitive conditions. This information provides better resolution of factors that are important for training programme design and skill development.

The bioenergetics of World Class Cycling

Professional cycle racing is one of the most demanding of all sports combining extremes of exercise duration, intensity and frequency. Riders are required to perform on a variety of surfaces (track, road, cross-country, mountain), terrains (level, uphill and downhill) and race situations (criterions, sprints, time trials, mass-start road races) in events ranging in duration from 10 s to 3 wk stage races covering 200 m to 4,000 km. Furthermore, professional road cyclists typically have approximately 100 race d/yr. Because of the diversity of cycle races, there are vastly different physiological demands associated with the various events. Until recently there was little information on the demands of professional cycling during training or competition. However, with the advent of reliable, valid bicycle crank dynanometers, it is now possible to quantify real-time power output, cadence and speed during a variety of track and road cycling races. This article provides novel data on the physiological demands of professional and world-class amateur cyclists and characterises some of the physiological attributes necessary for success in cycling at the élite level.

Racing cyclist power requirements in the 4000-m individual and team pursuits

PURPOSE

The purpose of this paper is: 1) to present field test data describing the power requirements of internationally competitive individual and team pursuiters, and 2) to develop a theoretical model for pursuit power based upon on these tests.

METHODS

In preparing U.S. cycling's pursuit team for the 1996 Atlanta Olympics, U.S. team scientists measured cycling power of seven subjects on the Atlanta track using a crank dynamometer (SRM) at speeds from 57 to 60 kph. By using these field data and other tests, mathematical models were devised which predict both individual and team pursuit performance. The field data indicate the power within a pace line at 60 kph averages 607 W in lead position (100%), 430 W in second position (70.8%), 389 W in third position (64.1%), and 389 W in fourth position (64.0%). A team member requires about 75% of the energy necessary for cyclists riding alone at the same speed. These results compare well with field measurements from a British pursuit team, to recent wind tunnel tests, and to earlier bicycle coast down tests.

RESULTS

The theoretical models predict performance with reasonable accuracy when the average power potential of an individual or team is known, or they may be used to estimate the power of pursuit competitors knowing race times. The model estimates that Christopher Boardman averaged about 520 W when setting his 1996, 4000-m individual pursuit record of 4 min 11.114 s and the Italian 4000-m pursuit team averaged about 480 W in setting their record of 4:00.958. Both used the "Superman" cycling position.

CONCLUSIONS

These records would be very difficult to break using less aerodynamic riding positions, due to the extraordinarily high power requirements.

Level ground and uphill cycling ability in professional road cycling

PURPOSE

To evaluate the physiological capacities and performance of professional road cyclists in relation to their morphotype-dependent speciality.

METHODS

24 world-class cyclists, classified as flat terrain (FT, N = 5), time trial (TT, N = 4), all terrain (AT, N = 6). and uphill (UH, N = 9) specialists, completed an incremental laboratory cycling test to assess maximal power output (Wmax), maximal oxygen uptake (VO2max), lactate threshold (LT), and onset of blood lactate accumulation (OBLA).

RESULTS

UH had a higher frontal area (FA):body mass (BM) ratio (5.23 +/- 0.09 m2 x kg(-1) x 10(-3)) than FT and TT (P < 0.05). FT showed the highest absolute Wmax (481 +/- 18 W), and UH the highest Wmax relative to BM (6.47 +/- 0.33 W x kg(-1)). WLT and W(OBLA) values were significantly higher in FT (356 +/- 41 and 417 +/- 45 W) and TT (357 +/- 41 and 409 +/- 46 W) than in UH (308 +/- 46 and 356 +/- 41). Scaling of these values relative to FA and BM exponents 0.32 and 0.79 minimized group differences, but considerable differences among mean group values remained. FT and TT had the highest Wmax per FA unit (1300 +/- 62 and 1293 +/- 57 W x m2), whereas TT had the highest absolute W x kg(-0.32) and W x kg(-0.79), as well as W x kg(-0.32), W x kg(-0.79), and W x m2 at the LT and OBLA.

CONCLUSIONS

i) Scaling of maximal and submaximal physiological values showed a performance advantage of TT over FT, AT, and UH in all cycling terrains and conditions; and ii) mass exponents of 0.32 and 1 were the most appropriate to evaluate level and uphill cycling ability, respectively, whereas absolute Wmax values are recommended for performance-prediction in short events on level terrain, and W(LT) and W(OBLA) in longer time trials and uphill cycling.

Prediction of elite schoolboy 2000m rowing ergometer performance from metabolic, anthropometric and strength variables

In 19 elite schoolboy rowers, the relationships between anthropometric characteristics, metabolic parameters, strength variables and 2000-m rowing ergometer performance time were analysed to test the hypothesis that a combination of these variables would predict performance better than either individual variables or one category of variables. Anthropometric characteristics, maximal oxygen uptake (VO2max), accumulated oxygen deficit, net efficiency, leg strength and 2000-m rowing ergometer time were measured. Body mass, VO2max and knee extension correlated with 2000-m performance time (r= -0.41, -0.43 and -0.40, respectively; P< 0.05), while net efficiency and accumulated oxygen deficit did not. Multiple-regression analyses indicated that the prediction model using anthropometric variables alone best predicts performance (R = 0.82), followed by the equation comprising body mass, VO2max and skinfolds (R = 0.80). Although the regression equations increased the predictive power from that obtained using single variables, the hypothesis that a prediction model consisting of variables from different physiological categories would predict performance better than variables from one physiological category was not supported.

Scaling of submaximal oxygen uptake with body mass and combined mass during uphill treadmill bicycling

This study examined the scaling relationships of net O2 uptake [V(O2)(net) = V(O2) - resting V(O2)] to body mass (MB) and combined mass (MC = MB + bicycle) during uphill treadmill bicycling. It was hypothesized that V(O2)(net) (l/min) would scale proportionally with MC [i.e., VO2(net) approximately M1.0C] and less than proportionally with MB [i.e., V(O2)(net) approximately MB]. Twenty-five competitive cyclists [73.9 +/- 8.8 and 85.0 +/- 9.0 (SD) kg for MB and MC, respectively] rode their bicycles on a treadmill at 3.46 m/s and grades of 1.7, 3.5, 5.2, and 7.0% while V(O2) was measured. Multiple log-linear regression procedures were applied to the pooled V(O2)(net) data to determine the exponents for MC and MB after statistically controlling for differences in treadmill grade and dynamic friction. The regression models were highly significant (R2 = 0.95, P < 0.001). Exponents for MC (0.99, 95% confidence interval = 0.80-1.18) and MB (0.89, 95% confidence interval = 0.72-1. 07) did not differ significantly from each other or 1.0. It was concluded that the 0.99 MC exponent was due to gravitational resistance, whereas the MB exponent was <1.0 because the bicycles were relatively lighter for heavier cyclists.

Altitude training at 2690m does not increase total haemoglobin mass or sea level VO2max in world champion track cyclists

Haemoglobin mass (Hb mass), maximum oxygen consumption (VO2max), simulated 4000 m individual pursuit cycling performance (IP4000), and haematological markers of red blood cell (RBC) turnover were measured in 8 male cyclists before and after (A) 31 d of altitude training at 2690 m. The dependent variables were measured serially after altitude on d A3-4, A8-9 and A20-21. There was no significant change in Hb mass over the course of the study and VO2max at d A9 was significantly lower than the baseline value (79.3 +/- 0.7 versus 81.4 +/- 0.6 ml x kg(-1) x min(-1), respectively). No increase in Hb mass or VO2max was probably due to initial values being close to the natural physiological limit with little scope for further change. When the IP4000 was analysed as a function of the best score on any of the three test days after altitude training there was a 4% improvement that was not reflected in a corresponding change in VO2max or Hb mass. RBC creatine concentration was significantly reduced after altitude training, suggesting a decrease in the average age of the RBC population. However, measurement of reticulocyte number and serum concentrations of erythropoietin, haptoglobin and bilirubin before and after altitude provided no evidence of increased RBC turnover. The data suggest that for these elite cyclists any benefit of altitude training was not from changes in VO2max or Hb mass, although this does not exclude the possibility of improved anaerobic capacity.

Reproducibility and validity of physiological parameters measured in cyclists riding on racing bikes placed on a stationary magnetic brake

The purpose of this study was: 1) To evaluate the reproducibility of physiological parameters measured during cycle exercise, and 2) To validate the predictive capacity of physiological parameters related to endurance performance. Therefore, physiological variables were measured twice during cycling exercise in a group of seven cyclists. Each cycle exercise session was separated by one week and included progressive submaximal cycling followed by a 5-km time trial. Two and three weeks later, endurance performance was evaluated by calculating average work output during a 50-km time trial (W50km). To simulate cycle performance, the cyclists' private racing bikes were placed on a stationary magnetic brake. No differences were observed between paired physiological observations in the test-retest (P>0.05). The coefficient of variation (CV) was calculated from the differences between test-retest parameters. CV for the maximal oxygen uptake (VO2max), average work output during the 5-km trial (W5km), the calculated work intensity which increased the blood lactate concentration to 2 and 4 mmol/l (W2mM and W4mM) and W50km were 1.9, 2.7, 6.1, 5.9 and 6.3%, respectively, while the 95% confidence interval (CI) showing the expected range for variation in a retest was calculated to be 80 ml.min(-1), 9, 16, 18 and 18 W, respectively. Simple linear regression showed significant correlations between VO2max, W5km, W2mM, W4mM and W50km (r-values: range 0.83-0.98, P<0.01).

IN CONCLUSION

1) Physiological parameters can be reproduced during an exercise test procedure in cyclists riding on racing bikes placed on a stationary magnetic brake, and 2) The validity of VO2max, W5km, W2mM, and W4mM as predictive parameters of endurance was demonstrated.

A new method for the calculation of constant supra-VO2peak power outputs

This investigation compared the variance in times to exhaustion among four different methods of supra-VO2peak power output calculation. Ten male subjects cycled to exhaustion at power outputs equivalent to 1) 120% VO2peak, 2) 6 W.kg-1, 3) 100% VO2peak + 10% of the peak anaerobic scope (PAS), and 4) 100% VO2peak + 20% of the mean anaerobic scope (MAS). PAS was defined as the difference between the peak power output (PPO) during a 30-s all-out cycle sprint and the power output at VO2peak MAS was defined as the difference between the mean power output (MPO) during a 30-s all-out cycle sprint and the power output at VO2peak. While the mean times to exhaustion for the four methods were not significantly different, the supra-VO2peak power output calculated as 120% VO2peak resulted in significantly more variance (P = 0.0173) in the times to exhaustion than did the power output equivalent to 20% MAS + 100% VO2peak (SE 16.2 s vs 6.9 s). The variance in time to exhaustion was significantly higher with the power output of 6 W.kg-1 than for the remaining three methods, while the variance in times to exhaustion at a power output of 10% PAS + 100% VO2peak was not significantly different from either 120% VO2peak or 20% MAS + 100% VO2peak. These results indicate that a supra-VO2peak power output that accounts for both aerobic ability and anaerobic work capacity (20% MAS + 100% VO2peak) results in less variance in time to exhaustion than a method which extrapolates the submaximal power output-VO2 relationship to a supramaximal intensity (120% VO2peak).

Methodological effects on the VO2-power regression and the accumulated O2 deficit

The VO2-power regression and O2 demand predicted for a supra-VO2peak intensity (i.e., 432 W) were determined in seven well-trained male cyclists (mean +/- SD: VO2peak = 5.29 +/- 0.51 l.min-1), using five incremental exercise protocols. These protocols were either continuous (CON) or discontinuous (DISCON), and comprised five to eight work bouts ranging in intensity between 40% and 85% VO2peak; the work bouts differed in duration (4-15 min), and the VO2 was measured during the 4th minute (CON4, DISCON4), from min 4 to 6 (DISCON6), 8 to 10 (DISCON10), or 13 to 15 (DISCON15) of each work bout. The y-intercepts of the VO2-power regressions were not different (P > 0.05), whereas the slope was higher (P < or = 0.01) when determined using DISCON10 (12.7 +/- 0.9 ml.min-1.W-1) and DISCON15 (12.5 +/- 0.9 ml.min-1.W-1) compared with DISCON6 (12.2 +/- 1.0 ml.min-1.W-1), DISCON4 (11.6 +/- 1.1 ml.min-1.W-1) or CON4 (11.9 +/- 0.7 ml.min-1.W-1). The O2 demand (at 432 W) was also higher (P < or = 0.01) for DISCON10 (6.05 +/- 0.29 l.min-1) and DISCON15 (6.05 +/- 0.28 l.min-1) compared with DISCON6 (5.88 +/- 0.31 l.min-1), DISCON4 (5.70 +/- 0.31 l.min-1) and CON4 (5.82 +/- 0.25 l.min-1). This demonstrates that the O2 demand predicted for high power outputs depends on the incremental protocol used.

Anaerobic ATP production and accumulated O2 deficit in cyclists

Anaerobic ATP production in skeletal muscle and the accumulated oxygen deficit (O2D) incurred during an exhaustive cycle bout (duration = 173 +/- 24 s; intensity = 112 +/- 3% VO2peak), were determined in 10 male cyclists (mean +/- SD: VO2peak = 69.8 +/- 4.2 ml.kg-1.min-1). Anaerobic ATP production (mmol.kg-1 d.w.) was determined from changes in lactate, phosphocreatine, ATP, and ADP in vastus lateralis. Muscle buffer value and the activities of glycogen phosphorylase (PHOS), phosphofructokinase and citrate synthase (CS) were also determined. The anaerobic ATP production determined from measured muscle metabolites was 202.7 +/- 46.9 mmol.kg-1 d.w. and was correlated (P < or = 0.05) with muscle buffer value (r = 0.81), PHOS (r = 0.69) and the ratio of PHOS to CS activity (r = 0.77). The O2D was 55.2 +/- 10.3 ml O2 Eq.kg-1, but was not correlated (P > 0.05) with anaerobic ATP production (r = -0.38), buffer value (r = -0.50) or PHOS (r = -0.39). These latter findings could be explained by error in measuring the O2D and/or muscle anaerobic ATP production in well-trained cyclists.

Relationship between gear ratio and 10-s sprint cycling on an air-braked ergometer

This investigation examined the relationship between gear ratio and peak and mean power outputs (PPO and MPO) and peak cadence (PC) during a 10-s all-out sprint on a multi-geared air-braked cycle ergometer. Ten physically active men [mean age 21.0 years (SEM 0.7)] performed in random order six 10-s sprints (15-min rest between each sprint) on two occasions (48 h apart) in six different gear ratios; flywheel revolutions per pedal crank revolution (FR/PCR) ranged between 5.22 and 11.61. The PPO, MPO, and PC were recorded from each sprint. Of the six gear ratios tested, a gear ratio eliciting 8.87 FR/PCR elicited the highest PPO for the initial test session; the PPO output of 1274 W was significantly greater (P < 0.01) than that produced in the other five gears. Analysis of data from the second test session revealed no statistically significant difference in PPO between gear ratios eliciting 8.00, 8.87, and 10.06 FR/PCR. The PPO from these three ratios were significantly greater (P < 0.05) than those produced using the ratios resulting in 6.32, 7.06, and 10.78 FR/PCR. The PC in the gear ratio maximising PPO was 120 rpm. Analysis of PC data revealed a significant decrease (P < 0.05) as the number of FR/PCR increased.