Correlates of simulated hill climb cycling performance

Photobiomodulation does not improve anaerobic performance in well-trained cyclists

To determine if photobiomodulation (PBM) has ergogenic effects on the anaerobic performance of well-trained cyclists. Fifteen healthy male road or mountain bike cyclists participated in this randomized, double-blinded, placebo-controlled, crossover study. Athletes were randomly assigned to receive photobiomodulation (630 nm, 4.6 J/cm², 6 J per point, 16 points, PBM session) or placebo intervention (PLA session) in the first session. The athletes then performed a 30-s Wingate test to determine mean and peak average power, relative power, mean and peak velocity, mean and peak RPM, fatigue index, total distance, time to peak power, explosive strength, and power drop. After 48 h, athletes returned to the laboratory for the crossover intervention. The repeated-measures ANOVA test followed by Bonferroni post hoc test or Friedman test with Dunn's post hoc test (p < 0.05), and Cohen's d statistic were used for comparisons. Performance in the Wingate test was not significantly different (p > 0.05) between PBM and PLA sessions for any variable. Only a small effect size was detected for time to peak power (-0.40; 1.11 to 0.31) and explosive strength (0.38; -0.34 to 1.09). We conclude that irradiation with red light, under a low energy density, does not promote ergogenic effects on the anaerobic performance of cycling athletes.

A data-driven approach to the "Everesting" cycling challenge

The "Everesting" challenge is a cycling activity in which a cyclist repeats a hill until accumulating an elevation gain equal to the elevation of Mount Everest in a single ride. The challenge experienced a surge in interest during the COVID-19 pandemic and the cancelation of cycling races around the world that prompted cyclists to pursue alternative, individual activities. The time to complete the Everesting challenge depends on the fitness and talent of the cyclist, but also on the length and gradient of the hill, among other parameters. Hence, preparing an Everesting attempt requires understanding the relationship between the Everesting parameters and the time to complete the challenge. We use web-scraping to compile a database of publicly available Everesting attempts, and we quantify and rank the parameters that determine the time to complete the challenge. We also use unsupervised machine learning algorithms to segment cyclists into distinct groups according to their characteristics and performance. We conclude that the power per unit body mass of the cyclist and the tradeoff between the gradient of the hill and the distance are the most important considerations when attempting the Everesting challenge. As such, elite cyclists best select a hill with gradient > 12%, whereas amateur and recreational cyclists best select a hill with gradient < 10% to minimize the time to complete the Everesting challenge.

Laboratory-Based Physical and Physiological Test Results That Serve as Predictors of Male, Amateur Road Cyclists' Performance Levels

Coetzee, B, and Malan, D. Laboratory-based physical and physiological test results that serve as predictors of male, amateur road cyclists' performance levels. J Strength Cond Res 32(10): 2897-2906, 2018-The purposes of this study were first, to determine the practical significant differences of laboratory-based physical and physiological test results between a selected group of successful and less successful amateur, male road cyclists from Africa; and second, to determine the significance, adequacy, accurateness, and usefulness of laboratory-based physical and physiological test results to serve as predictors of these amateur, male road cyclists' performance levels. Male road cyclists, identified as the top amateur road cyclists of the cycling federations of 13 African countries, were subjected to a test battery for the measurement of lower-body flexibility, abdominal strength, peak and average anaerobic power output as well as maximum aerobic power. Practical significant differences between the successful and less successful road cyclists were found for almost all the Wingate related variables, some of the sub-maximum parameters, and most of the maximum physiological variables. Finally, the abdominal muscle strength test value, vertical jump distance, Wingate relative peak power, and respiratory compensation point expressed as percentage of V[Combining Dot Above]O2max and as relative power output were the physiological components that acted as adequate, accurate, and useful predictors of performance levels. Coaches and sport scientists should therefore include these components in testing protocols that are aimed at evaluating and improving cyclists' physical conditioning programs.

Does Cold Water or Ice Slurry Ingestion During Exercise Elicit a Net Body Cooling Effect in the Heat?

Cold water or ice slurry ingestion during exercise seems to be an effective and practical means to improve endurance exercise performance in the heat. However, transient reductions in sweating appear to decrease the potential for evaporative heat loss from the skin by a magnitude that at least negates the additional internal heat loss as a cold ingested fluid warms up to equilibrate with body temperature; thus explaining equivalent core temperatures during exercise at a fixed heat production irrespective of the ingested fluid temperature. Internal heat transfer with cold fluid/ice is always 100% efficient; therefore, when a decrement occurs in the efficiency that sweat evaporates from the skin surface (i.e. sweating efficiency), a net cooling effect should begin to develop. Using established relationships between activity, climate and sweating efficiency, the boundary conditions beyond which cold ingested fluids are beneficial in terms of increasing net heat loss can be calculated. These conditions are warmer and more humid for cycling relative to running by virtue of the greater skin surface airflow, which promotes evaporation, for a given metabolic heat production and thus sweat rate. Within these boundary conditions, athletes should ingest fluids at the temperature they find most palatable, which likely varies from athlete to athlete, and therefore best maintain hydration status. The cooling benefits of cold fluid/ice ingestion during exercise are likely disproportionately greater for athletes with physiological disruptions to sweating, such as those with a spinal cord injury or burn injuries, as their capacity for skin surface evaporative heat loss is much lower; however, more research examining these groups is needed.

The Lactate Minimum Test: Concept, Methodological Aspects and Insights for Future Investigations in Human and Animal Models

In 1993, Uwe Tegtbur proposed a useful physiological protocol named the lactate minimum test (LMT). This test consists of three distinct phases. Firstly, subjects must perform high intensity efforts to induce hyperlactatemia (phase 1). Subsequently, 8 min of recovery are allowed for transposition of lactate from myocytes (for instance) to the bloodstream (phase 2). Right after the recovery, subjects are submitted to an incremental test until exhaustion (phase 3). The blood lactate concentration is expected to fall during the first stages of the incremental test and as the intensity increases in subsequent stages, to rise again forming a “U” shaped blood lactate kinetic. The minimum point of this curve, named the lactate minimum intensity (LMI), provides an estimation of the intensity that represents the balance between the appearance and clearance of arterial blood lactate, known as the maximal lactate steady state intensity (iMLSS). Furthermore, in addition to the iMLSS estimation, studies have also determined anaerobic parameters (e.g., peak, mean, and minimum force/power) during phase 1 and also the maximum oxygen consumption in phase 3; therefore, the LMT is considered a robust physiological protocol. Although, encouraging reports have been published in both human and animal models, there are still some controversies regarding three main factors: (1) the influence of methodological aspects on the LMT parameters; (2) LMT effectiveness for monitoring training effects; and (3) the LMI as a valid iMLSS estimator. Therefore, the aim of this review is to provide a balanced discussion between scientific evidence of the aforementioned issues, and insights for future investigations are suggested. In summary, further analyses is necessary to determine whether these factors are worthy, since the LMT is relevant in several contexts of health sciences.

Laboratory predictors of uphill cycling performance in trained cyclists

This study aimed to assess the relationship between an uphill time-trial (TT) performance and both aerobic and anaerobic parameters obtained from laboratory tests. Fifteen cyclists performed a Wingate anaerobic test, a graded exercise test (GXT) and a field-based 20-min TT with 2.7% mean gradient. After a 5-week non-supervised training period, 10 of them performed a second TT for analysis of pacing reproducibility. Stepwise multiple regressions demonstrated that 91% of TT mean power output variation (W kg^-1) could be explained by peak oxygen uptake (ml kg^-1.min^-1) and the respiratory compensation point (W kg^-1), with standardised beta coefficients of 0.64 and 0.39, respectively. The agreement between mean power output and power at respiratory compensation point showed a bias ± random error of 16.2 ± 51.8 W or 5.7 ± 19.7%. One-way repeated-measures analysis of variance revealed a significant effect of the time interval (123.1 ± 8.7; 97.8 ± 1.2 and 94.0 ± 7.2% of mean power output, for epochs 0-2, 2-18 and 18-20 min, respectively; P < 0.001), characterising a positive pacing profile. This study indicates that an uphill, 20-min TT-type performance is correlated to aerobic physiological GXT variables and that cyclists adopt reproducible pacing strategies when they are tested 5 weeks apart (coefficients of variation of 6.3; 1 and 4%, for 0-2, 2-18 and 18-20 min, respectively).

Anaerobic power in road cyclists is improved after 10 weeks of whole-body vibration training

Whole-body vibration (WBV) training has previously improved muscle power in various athletic groups requiring explosive muscle contractions. To evaluate the benefit of including WBV as a training adjunct for improving aerobic and anaerobic cycling performance, road cyclists (n = 9) performed 3 weekly, 10-minute sessions of intermittent WBV on synchronous vertical plates (30 Hz) while standing in a static posture. A control group of cyclists (n = 8) received no WBV training. Before and after the 10-week intervention period, lean body mass (LBM), cycling aerobic peak power (Wmax), 4 mM lactate concentration (OBLA), VO2peak, and Wingate anaerobic peak and mean power output were determined. The WBV group successfully completed all WBV sessions but reported a significant 30% decrease in the weekly cycling training time (pre: 9.4 ± 3.3 h·wk(-1); post: 6.7 ± 3.7 h·wk(-1); p = 0.01) that resulted in a 6% decrease in VO2peak and a 4% decrease in OBLA. The control group reported a nonsignificant 6% decrease in cycling training volume (pre: 9.5 ± 3.6 h·wk(-1); 8.6 ± 2.9 h·wk(-1); p = 0.13), and all measured variables were maintained. Despite the evidence of detraining in the WBV group, Wmax was maintained (pre: 258 ± 53 W; post: 254 ± 57 W; p = 0.43). Furthermore, Wingate peak power increased by 6% (668 ± 189 to 708 ± 220 W; p = 0.055), and Wingate mean power increased by 2% (553 ± 157 to 565 ± 157 W; p = 0.006) in the WBV group from preintervention to postintervention, respectively, without any change to LBM. The WBV training is an attractive training supplement for improving anaerobic power without increasing muscle mass in road cyclists.

Relationship between anaerobic cycling tests and mountain bike cross-country performance

Despite its apparent relevance, there is no evidence supporting the importance of anaerobic metabolism in Olympic crosscountry mountain biking (XCO). The purpose of this study was to examine the correlation between XCO race time and performance indicators of anaerobic power. Ten XCO riders (age: 28 ± 5 years; weight: 68.7 ± 7.7 kg; height: 177.9 ± 7.4 cm; estimated body fat: 5.7 ± 2.8%; estimated ·VO₂max: 68.4 ± 5.7 ml·kg⁻¹·min⁻¹) participating in the Lagos Mountain Bike Championship (Brazil) completed 2 separate testing sessions before the race. In the first session, after anthropometric assessments were performed, the cyclists completed a single 30-second Wingate (WIN) test and an intermittent tests consisting of 5 × 30-second WIN tests (50% of the single WIN load) with 30 seconds of recovery between trials. In the second session, the riders performed a maximal incremental test. A significant correlation was found between race time and maximal power on the 5× WIN test (r = -0.79, IC(95%) -0.94 to -0.32, p = 0.006) and the mean average power on the 5× WIN test normalized by body mass (r = -0.63, IC(95%) -0.90 to -0.01, p = 0.048). The finding of the study supports the use of anaerobic tests for assessing mountain bikers participating in XCO competitions and suggests that anaerobic power is an important determinant of performance.

Relationships between triathlon performance and pacing strategy during the run in an international competition

PURPOSE

The purpose of the present study was to examine relationships between athlete's pacing strategies and running performance during an international triathlon competition.

METHODS

Running split times for each of the 107 finishers of the 2009 European Triathlon Championships (42 females and 65 males) were determined with the use of a digital synchronized video analysis system. Five cameras were placed at various positions of the running circuit (4 laps of 2.42 km). Running speed and an index of running speed variability (IRSVrace) were subsequently calculated over each section or running split.

RESULTS

Mean running speed over the first 1272 m of lap 1 was 0.76 km·h-1 (+4.4%) and 1.00 km·h-1 (+5.6%) faster than the mean running speed over the same section during the three last laps, for females and males, respectively (P < .001). A significant inverse correlation was observed between RSrace and IRSVrace for all triathletes (females r = -0.41, P = .009; males r = -0.65, P = .002; and whole population -0.76, P = .001). Females demonstrated higher IRSVrace compared with men (6.1 ± 0.5 km·h-1 and 4.0 ± 1.4 km·h-1, for females and males, respectively, P = .001) due to greater decrease in running speed over uphill sections.

CONCLUSIONS

Pacing during the run appears to play a key role in high-level triathlon performance. Elite triathletes should reduce their initial running speed during international competitions, even if high levels of motivation and direct opponents lead them to adopt an aggressive strategy.

Aspectos fisiológicos do mountain biking competitivo

A prática do ciclismo off-road (mountain biking - MTB), cresceu muito nas últimas duas décadas, sendo incluído como esporte olímpico, nos Jogos de Atlanta em 1996, na modalidade Cross Country. Na última década, houve um aumento no número de publicações científicas que verificaram a demanda fisiológica durante competições, assim como o estudo de possíveis preditores da performance nesta modalidade. O objetivo deste estudo de revisão foi descrever alguns aspectos fisiológicos específicos do MTB Cross Country (MTB CC) competitivo (intensidade de provas, perfil fisiológico de atletas de elite, uso de suspensões e determinantes da performance em subidas). Observa-se na literatura analisada que as provas de MTB CC parecem impor uma sobrecarga fisiológica maior, quando analisada através da frequência cardíaca, do que provas de ciclismo de estrada com duração semelhante. Entretanto, quando analisada pela potência de pedalada, observa-se claramente a característica intermitente da modalidade, com variações de potência durante a prova entre zero e 500W, e potência média relativamente baixa em comparação aos valores de FC encontrados. Outro fator importante levantado neste estudo são as alterações fisiológicas decorrentes do uso de suspensões nas bicicletas de MTB CC. O uso deste equipamento reduz o estresse muscular provocado pelo terreno acidentado, embora pareça não afetar o gasto energético total, tanto em percurso plano como em subidas. Entretanto, é fato que o desempenho em circuitos acidentados é melhorado com o uso das suspensões. Com base nos estudos abordados nessa revisão, conclui-se que o MTB CC enquanto modalidade competitiva apresenta uma grande variação de intensidade (avaliada através da potência), sendo esta atribuída principalmente ao tipo de terreno (irregular e com muitas aclives e declives acentuados) em que as provas de MTB CC acontecem.

Effects of sprint interval training and body weight reduction on power to weight ratio in experienced cyclists

The purpose of this study was to determine the effect of supramaximal sprint interval training (SIT), body weight reduction, and a combination of both treatments on peak and average anaerobic power to weight ratio (PPOan:Wt, APOan:Wt) by manipulating peak and average anaerobic power output (PPOan, APOan) and body weight (BW) in experienced cyclists. Participants (N = 34, age = 38.0 +/- 7.1 years) were assigned to 4 groups for a 10-week study. One group performed twice-weekly SIT sessions on a cycle ergometer while maintaining body weight (SIT). A second group did not perform SIT but intentionally reduced body weight (WR). A third group simultaneously performed SIT sessions and reduced body weight (SIT+WR). A control group cycled in their normal routine and maintained body weight (CON). The 30-second Wingate Test assessed pretest and posttest POan:Wt scores. There was a significant mean increase (p < 0.05) from pretest to posttest in PPOan:Wt and APOan:Wt (W x kg(-1)) scores in both SIT (10.82 +/- 1.71 to 11.92 +/- 1.77 and 8.05 +/- 0.64 to 8.77 +/- 0.64, respectively) and WR (10.33 +/- 2.91 to 11.29 +/- 2.80 and 7.04 +/- 1.45 to 7.62 +/- 1.24, respectively). PPOan and APOan (W) increased significantly only in SIT (753.7 +/- 121.0 to 834.3 +/- 150.1 and 561.3 +/- 62.5 to 612.7 +/- 69.0, respectively). Body weight (kg) decreased significantly in WR and SIT + WR (80.3 +/- 13.7 to 75.3 +/- 11.9 and 78.9 +/- 10.8 to 73.4 +/- 10.8, respectively). The results demonstrate that cyclists can use SIT sessions and body weight reduction as singular training interventions to effect significant increases in anaerobic power to weight ratio, which has been correlated to enhanced aerobic cycling performance. However, the treatments were not effective as combined interventions, as there was no significant change in either PPOan:Wt or APOan:Wt in SIT + WR.

Adaptation of pedaling rate of professional cyclist in mountain passes

The aim of this study was to analyze the pedaling rate (PR) adopted by professional cyclists in different mountain passes. PR, heart rate (HR), velocity and power to overcome gravity were monitored during special (HM), 1st (M1), 2nd (M2) and 3rd (M3) category mountain passes. HM and M1 within high-mountain stages were classified into mountain passes before the final mountain pass of the stage (M-BF) and mountain passes placed in the final of the stage (M-F). PR was significantly higher (P < 0.05) in M3 (82 +/- 1 rpm) than that in M2 (75 +/- 3 rpm), M1 (75 +/- 2 rpm) and HM (73 +/- 1 rpm). Velocity and power output decreased in the following order: M3, M2, M1 and HM. Also, greater values (P < 0.05) were observed in M-BF (24.1 +/- 0.8 km h(-1) and 308.5 +/- 10.4 W) and in M-F (17.6 +/- 0.9 km h(-1) and 270.1 +/- 9.9 W). In addition, PR was higher (P < 0.05) in M-BF (79 +/- 2 rpm) than that in M-F (73 +/- 1 rpm). In conclusion, PR was modified according to the characteristics and the race strategies adopted by the cyclists, thus the cyclists chose higher PR to improve their performance.

Field and laboratory correlates of performance in competitive cross-country mountain bikers

We designed a laboratory test with variable fixed intensities to simulate cross-country mountain biking and compared this to more commonly used laboratory tests and mountain bike performance. Eight competitive male mountain bikers participated in a cross-country race and subsequently did six performance tests: an individual outdoor time trial on the same course as the race and five laboratory tests. The laboratory tests were as follows: an incremental cycle test to fatigue to determine peak power output; a 26-min variable fixed-intensity protocol using an electronically braked ergometer followed immediately by a 1-km time trial using the cyclist's own bike on an electronically braked roller ergometer; two 52-min variable fixed-intensity protocols each followed by a 1-km time trial; and a 1-km time trial done on its own. Outdoor competition time and outdoor time trial time correlated significantly (r = 0.79, P < 0.05). Both outdoor tests correlated better with peak power output relative to body mass (both r = -0.83, P < 0.05) than absolute peak power output (outdoor competition: r = -0.65; outdoor time trial: r = -0.66; non-significant). Outdoor performance times did not correlate with the laboratory tests. We conclude that cross-country mountain biking is similar to uphill or hilly road cycling. Further research is required to design sport-specific tests to determine the remaining unexplained variance in performance.

Pacing during an elite Olympic distance triathlon: comparison between male and female competitors

This study investigated whether pacing differed between 68 male and 35 female triathletes competing over the same ITU World Cup course. Swimming, cycling and running velocities (m s(-1) and km h(-1)) were measured using a global positioning system (Garmin, UK), video analysis (Panasonic NV-MX300EG), and timing system (Datasport, Switzerland). The relationship between performance in each discipline and finishing position was determined. Speed over the first 222 m of the swim was associated with position (r=-0.88 in males, r=-0.97 in females, both p<0.01) and offset from the leader, at the swim finish (r=-0.42 in males, r=-0.49 in females, both p<0.01). The latter affected which pack number was attained in bike lap 1 (r=0.81 in males, r=0.93 in females, both p<0.01), bike finishing position (both r=0.41, p<0.01) and overall finishing position (r=0.39 in males, r=0.47 in females, both p<0.01). Average biking speed, and both speed and pack attained in bike laps 1 and 2, influenced finishing position less in the males (r=-0.42, -0.2 and -0.42, respectively, versus r=-0.74, -0.75, and -0.72, respectively, in the females, all p<0.01). Average run speed correlated better with finishing position in males (r=-0.94, p<0.01) than females (r=-0.71, p<0.001). Both sexes ran faster over the first 993 m than most other run sections but no clear benefit of this strategy was apparent. The extent to which the results reflect sex differences in field size and relative ability in each discipline remains unclear.

Optimal power-to-mass ratios when predicting flat and hill-climbing time-trial cycling

The purpose of this article was to establish whether previously reported oxygen-to-mass ratios, used to predict flat and hill-climbing cycling performance, extend to similar power-to-mass ratios incorporating other, often quick and convenient measures of power output recorded in the laboratory [maximum aerobic power (W(MAP)), power output at ventilatory threshold (W(VT)) and average power output (W(AVG)) maintained during a 1 h performance test]. A proportional allometric model was used to predict the optimal power-to-mass ratios associated with cycling speeds during flat and hill-climbing cycling. The optimal models predicting flat time-trial cycling speeds were found to be (W(MAP)m(-0.48))(0.54), (W(VT)m(-0.48))(0.46) and (W(AVG)m(-0.34))(0.58) that explained 69.3, 59.1 and 96.3% of the variance in cycling speeds, respectively. Cross-validation results suggest that, in conjunction with body mass, W(MAP) can provide an accurate and independent prediction of time-trial cycling, explaining 94.6% of the variance in cycling speeds with the standard deviation about the regression line, s=0.686 km h(-1). Based on these models, there is evidence to support that previously reported VO2-to-mass ratios associated with flat cycling speed extend to other laboratory-recorded measures of power output (i.e. Wm(-0.32)). However, the power-function exponents (0.54, 0.46 and 0.58) would appear to conflict with the assumption that the cyclists' speeds should be proportional to the cube root (0.33) of power demand/expended, a finding that could be explained by other confounding variables such as bicycle geometry, tractional resistance and/or the presence of a tailwind. The models predicting 6 and 12% hill-climbing cycling speeds were found to be proportional to (W(MAP)m(-0.91))(0.66), revealing a mass exponent, 0.91, that also supports previous research.

Caffeine lowers perceptual response and increases power output during high-intensity cycling

The aim of this study was to determine the effects of caffeine ingestion on a 'preloaded' protocol that involved cycling for 2 min at a constant rate of 100% maximal power output immediately followed by a 1-min 'all-out' effort. Eleven male cyclists completed a ramp test to measure maximal power output. On two other occasions, the participants ingested caffeine (5 mg. kg(-1)) or placebo in a randomized, double-blind procedure. All tests were conducted on the participants' own bicycles using a Kingcycle test rig. Ratings of perceived exertion (RPE; 6-20 Borg scale) were lower in the caffeine trial by approximately 1 RPE point at 30, 60 and 120 s during the constant rate phase of the preloaded test (P <0.05). The mean power output during the all-out effort was increased following caffeine ingestion compared with placebo (794+/-164 vs 750+/-163 W; P=0.05). Blood lactate concentration 4, 5 and 6 min after exercise was also significantly higher by approximately 1 mmol. l(-1) in the caffeine trial (P <0.05). These results suggest that high-intensity cycling performance can be increased following moderate caffeine ingestion and that this improvement may be related to a reduction in RPE and an elevation in blood lactate concentration.

Science and cycling: current knowledge and future directions for research

In this holistic review of cycling science, the objectives are: (1) to identify the various human and environmental factors that influence cycling power output and velocity; (2) to discuss, with the aid of a schematic model, the often complex interrelationships between these factors; and (3) to suggest future directions for research to help clarify how cycling performance can be optimized, given different race disciplines, environments and riders. Most successful cyclists, irrespective of the race discipline, have a high maximal aerobic power output measured from an incremental test, and an ability to work at relatively high power outputs for long periods. The relationship between these characteristics and inherent physiological factors such as muscle capilliarization and muscle fibre type is complicated by inter-individual differences in selecting cadence for different race conditions. More research is needed on high-class professional riders, since they probably represent the pinnacle of natural selection for, and physiological adaptation to, endurance exercise. Recent advances in mathematical modelling and bicycle-mounted strain gauges, which can measure power directly in races, are starting to help unravel the interrelationships between the various resistive forces on the bicycle (e.g. air and rolling resistance, gravity). Interventions on rider position to optimize aerodynamics should also consider the impact on power output of the rider. All-terrain bicycle (ATB) racing is a neglected discipline in terms of the characterization of power outputs in race conditions and the modelling of the effects of the different design of bicycle frame and components on the magnitude of resistive forces. A direct application of mathematical models of cycling velocity has been in identifying optimal pacing strategies for different race conditions. Such data should, nevertheless, be considered alongside physiological optimization of power output in a race. An even distribution of power output is both physiologically and biophysically optimal for longer ( > 4 km) time-trials held in conditions of unvarying wind and gradient. For shorter races (e.g. a 1 km time-trial), an 'all out' effort from the start is advised to 'save' time during the initial phase that contributes most to total race time and to optimize the contribution of kinetic energy to race velocity. From a biophysical standpoint, the optimum pacing strategy for road time-trials may involve increasing power in headwinds and uphill sections and decreasing power in tailwinds and when travelling downhill. More research, using models and direct power measurement, is needed to elucidate fully how much such a pacing strategy might save time in a real race and how much a variable power output can be tolerated by a rider. The cyclist's diet is a multifactorial issue in itself and many researchers have tried to examine aspects of cycling nutrition (e.g. timing, amount, composition) in isolation. Only recently have researchers attempted to analyse interrelationships between dietary factors (e.g. the link between pre-race and in-race dietary effects on performance). The thermal environment is a mediating factor in choice of diet, since there may be competing interests of replacing lost fluid and depleted glycogen during and after a race. Given the prevalence of stage racing in professional cycling, more research into the influence of nutrition on repeated bouts of exercise performance and training is required.

Level ground and uphill cycling efficiency in seated and standing positions

PURPOSE

This study was designed to examine the effects of cycling position (seated or standing) during level-ground and uphill cycling on gross external efficiency (GE) and economy (EC).

METHODS

Eight well-trained cyclists performed in a randomized order five trials of 6-min duration at 75% of peak power output either on a velodrome or during the ascent of a hill in seated or standing position. GE and EC were calculated by using the mechanical power output that was measured by crankset (SRM) and energy consumption by a portable gas analyzer (Cosmed K4b(2)). In addition, each subject performed three 30-s maximal sprints on a laboratory-based cycle ergometer or in the field either in seated or standing position.

RESULTS

GE and EC were, respectively, 22.4 +/- 1.5% (CV = 5.6%) and 4.69 +/- 0.33 kJ x L(-1) (CV = 5.7%) and were not different between level seated, uphill seated, or uphill standing conditions. Heart rate was significantly ( < 0.05) higher in standing position. In the uphill cycling trials, minute ventilation was higher ( < 0.05) in standing than in seated position. The average 30-s power output was higher ( < 0.01) in standing (803 +/- 103 W) than in seated position (635 +/- 123 W) or on the stationary ergometer (603 +/- 81 W).

CONCLUSION

Gradient or body position appears to have a negligible effect on external efficiency in field-based high-intensity cycling exercise. Greater short-term power can be produced in standing position, presumably due to a greater force developed per revolution. However, the technical features of the standing position may be one of the most determining factors affecting the metabolic responses.