Uphill Cycling Research Articles

Comparison of Predicted and Measured Power Output During Uphill Cycling

Evaluation of competitive cycling performance is often based on either measured power output (PO) or estimates based on equations derived from the literature. In many of the major international cycling events, comparative analyses of performance are common, based solely on prediction equations PURPOSE: To determine the accuracy of published equations for predicting uphill cycling PO vs direct measurements.FigureMETHODS: Well-trained cyclists (n=8) performed 6 rides each (2 courses with different gradients × 3 relative speeds). Each ride was >5 min in duration. Climb equations based on speed, grade, cyclists + bike weight http://www.me.psu.edu/lamancusa/ProdDiss/Bicycle/bikecalc1.htm based on GPS measurements of positional change were used to predict PO. Direct PO was measured using an in-wheel power meter (PowerTap). RESULTS: Predicted PO and measured PO (within the range of 140-400W) were highly related (r=0.989), with an essentially zero value for intercept. CONCLUSIONS: Without correction for wind, altitude or the effect of additional riders, the relationship between predicted and measured PO during cycling was very strong, supporting the value of published climb equations.

Effects of low and high cadence interval training on power output in flat and uphill cycling time-trials

This study tested the effects of low-cadence (60 rev min(-1)) uphill (Int(60)) or high-cadence (100 rev min(-1)) level-ground (Int(100)) interval training on power output (PO) during 20-min uphill (TT(up)) and flat (TT(flat)) time-trials. Eighteen male cyclists ([Formula: see text]: 58.6 ± 5.4 mL min(-1) kg(-1)) were randomly assigned to Int(60), Int(100) or a control group (Con). The interval training comprised two training sessions per week over 4 weeks, which consisted of six bouts of 5 min at the PO corresponding to the respiratory compensation point (RCP). For the control group, no interval training was conducted. A two-factor ANOVA revealed significant increases on performance measures obtained from a laboratory-graded exercise test (GXT) (P (max): 2.8 ± 3.0%; p < 0.01; PO and [Formula: see text] at RCP: 3.6 ± 6.3% and 4.7 ± 8.2%, respectively; p < 0.05; and [Formula: see text] at ventilatory threshold: 4.9 ± 5.6%; p < 0.01), with no significant group effects. Significant interactions between group and uphill and flat time-trial, pre- versus post-training on PO were observed (p < 0.05). Int(60) increased PO during both TT(up) (4.4 ± 5.3%) and TT(flat) (1.5 ± 4.5%). The changes were -1.3 ± 3.6, 2.6 ± 6.0% for Int(100) and 4.0 ± 4.6%, -3.5 ± 5.4% for Con during TT(up) and TT(flat), respectively. PO was significantly higher during TT(up) than TT(flat) (4.4 ± 6.0; 6.3 ± 5.6%; pre and post-training, respectively; p < 0.001). These findings suggest that higher forces during the low-cadence intervals are potentially beneficial to improve performance. In contrast to the GXT, the time-trials are ecologically valid to detect specific performance adaptations.

Fatigue level after maximal exercise test (laboratory and road) in cyclists

Cordova A, Sainz J, Cuervas-Mons M, Tur JA, Pons A. Fatigue level after maximal exercise test (laboratory and road) in cyclists. J. Hum. Sport Exerc. Vol. 5, No. 3, pp. 358-369, 2010. Despite the importance of uphill cycling performance during cycling competitions, there is very little research investigating uphill cycling, particularly concerning field studies. The lack of research is partly due to the difficulties in obtaining data in the field. The aim of this study was analyze the fatigue after a maximal exercise test and the maximal blood lactate in elite cyclists after two maximal exercises, one on laboratory and other in field. In this study 14 semi-professional cyclists have participated. The trials consisted in a laboratory incremental test (LIT) to exhaustion, and a maximal individual uphill time trial test on road (UTT) (5.85±0.24% slope) during 12-minute. The results showed that in LIT the maximal heart rate (HRmax) (beats·min -1 ) was 188±9.8, with a maximum of blood lactate (LAmax) (mmol·L -1 ) of 13.9±2.5. Similar data were obtained in the 12 min maximal UTT (LAmax 15.2±3.1 mmol·L -1 , and HRmax 188±6.5 beats·min -1 ). A high correlation of LAmax (0.70) and HRmax (0.86) was obtained from both trials. No differences were observed with respect the fatigue data (psychological and dynamometric) between both test LIT vs UTT.We conclude that UTT test on road as a useful test to evaluate the cyclist’s physical condition. We think that is perfectly valid, reliable and reproducible, and is possible to carried by the made for the own cyclist or for the trainers. On the other hand, is important because we can obtain information about of performance as well as power feeling of cyclist. These results may be significant in physiological terms to monitor the training and for

Effect of posture change and alternation, on efficiency, blood lactate concentration and muscle activity during uphill cycling.

Effect of posture change and alternation, on efficiency, blood lactate concentration and muscle activity during uphill cycling.

Seated versus standing position for maximization of performance during intense uphill cycling

It is not known whether the seated or standing position favours performance during intensive bouts of uphill cycling. The following hypotheses were therefore tested: (1) the standing position results in better performance at a high power output, while (2) the seated position is best at a moderate power output. We also assessed the seated–standing transition intensity, above which seated cycling should be superseded by standing cycling for maximization of performance. Ten male cyclists (mean age 27 years, s = 3; height 1.82 m, s = 0.07; body mass 75.2 kg, s = 7.0; [Vdot]O2max 70.0 ml · kg−1 · min−1, s = 5.2) performed seated and standing treadmill cycling to exhaustion at 10% grade and at four power outputs ranging from 86% to 165% of their power output at maximal oxygen uptake (Wmax). Power output at maximal oxygen uptake was obtained during determination of [Vdot]O2max. There was no difference in time to exhaustion between the two cycling positions at 86% of Wmax (P = 0.29). All participants performed best at the highest power output (165% of Wmax) when standing (P = 0.002). An overall seated–standing transition intensity of 94% of Wmax was identified. Thus, in general, cyclists may choose either the standing or seated position for maximization of performance at a submaximal intensity of 86% of Wmax, while the standing position should be used at intensities above 94% of Wmax and approaching 165% of Wmax.

Allometric Scaling of Uphill Cycling Performance

Previous laboratory-based investigations have identified optimal body mass scaling exponents in the range 0.79-0.91 for uphill cycling. The purpose of this investigation was to evaluate whether or not these exponents are also valid in a field setting. A proportional allometric model was used to predict the optimal power-to-mass ratios associated with road-based uphill time-trial cycling performance. The optimal power function models predicting mean cycle speed during a 5.3 km, 5.4% road hill-climb time-trial were (VO(2max) x m(-1.24))(0.55) and (RMP(max) x m(-1.04))(0.54), explained variance being 84.6% and 70.5%, respectively. Slightly higher mass exponents were observed when the mass predictor was replaced with the combined mass of cyclist and equipment (m(C)). Uphill cycling speed was proportional to (VO(2max) x m(C)(-1.33))(0.57) and (RMP(max) x m(C)(-1.10))(0.59). The curvilinear exponents, 0.54-0.59, identified a relatively strong curvilinear relationship between cycling speed and energy cost, suggesting that air resistance remains influential when cycling up a gradient of 5.4%. These results provide some support for previously reported uphill cycling mass exponents derived in laboratories. However, the exponents reported here were a little higher than those reported previously, a finding possibly explained by a lack of geometric similarity in this sample.

Exercise intensity and load during uphill cycling in professional 3-week races

This study examined the exercise intensity and load of the mountain passes of the major 3-week races according to their difficulty (length and slope) and position within the stage, using competition heart rate (HR). Sixteen world-class cyclists performed a laboratory test to assess maximal power output (W (max)), maximal HR (HR(max)), HR reserve (HRR), onset of blood lactate accumulation (OBLA), lactate threshold (LT) and a HR-power output relationship. HR was monitored during 68 OFF, 172 FIRST, and 134 SECOND category passes. Passes were also classified as BEGINNING, MIDDLE or END if they were placed in the first, second or final thirds of a stage, respectively. The training impulse (TRIMP) was calculated from HR and climb duration. %HRR was significantly higher in OFF and FIRST (77 +/- 7% in both), than SECOND (74 +/- 7%). Competition HR relative to HR(OBLA)R and HR(LT)R were higher in OFF (86 +/- 8, 98 +/- 11%) and FIRST (87 +/- 7, 100 +/- 11%) than SECOND (83 +/- 9, 95 +/- 13%). %HRR was lower in OFF situated in BEGINNING (66 +/- 1%) than in MIDDLE (82 +/- 5%) and END (77 +/- 7%); in FIRST situated in BEGINNING (74 +/- 9%) than in MIDDLE (79 +/- 5%); and in SECOND situated in BEGINNING (69 +/- 9%) compared to END (75 +/- 8%). The amount of TRIMP in OFF, FIRST and SECOND were 115 +/- 30, 72 +/- 29 and 41 +/- 19 (P < 0.05). In conclusion, the present study showed that mountain passes are highly demanding and that their intensity is related not only to the difficulty of the ascents but also to the position within the stage. The knowledge of these demands could be useful for planning pre-competition training strategies.

Level ground and uphill cycling ability in elite female mountain bikers and road cyclists

This study compared the morphological and physiological characteristics of elite female mountain bikers with road cyclists of different specialties and competitive level. Twenty-seven professional road cyclists and 12 mountain bikers (MTB) were involved. Road cyclists were classified as flat specialists (n = 10, FL), time trialists (n = 5, TT) and climbers (n = 12, C). From these cyclists two subgroups were obtained and compared: world class road cyclists (n = 5) and MTB (n = 5). Maximum oxygen uptake, peak power output, oxygen uptake at respiratory compensation point and power output at respiratory compensation point were determined in the laboratory. Body surface area and frontal area were also estimated. TT and FL showed higher body mass, body surface and frontal area compared with C and MTB. Absolute physiological parameters were generally higher in TT than the other groups. The same parameters normalized by body mass were similar between TT, C and MTB but higher compared to FL. No differences were found between world class road cyclists compared with top level MTB. These results confirm that a cyclist's morphological characteristics are important determinants of female cycling performance. Female MTB have anthropometric characteristics similar to road climbers, whilst the physiological profile was not different between time trialists and climbers. This suggests that, as for male professional cyclists, top level time trialists have an overall performance advantage over all types of terrain.

Influence of Hydration Status on Thermoregulation and Cycling Hill Climbing

Although dehydration can impair endurance performance, a reduced body mass may benefit uphill cycling by increasing the power-to-mass ratio. This study examined the effects of a reduction in body mass attributable to unreplaced sweat losses on simulated cycling hill-climbing performance in the heat. Eight well-trained male cyclists (mean +/- SD: 28.4 +/- 5.7 yr; 71.0 +/- 5.9 kg; 176.7 +/- 4.7 cm; VO2peak: 66.2 +/- 5.8 mL x kg(-1) x min(-1)) completed a maximal graded cycling test on a stationary ergometer to determine maximal aerobic power (MAP). In a randomized crossover design, cyclists performed a 2-h ride at 53% MAP on a stationary ergometer, immediately followed by a cycling hill-climb time-to-exhaustion trial (88% MAP) on their own bicycle on an inclined treadmill (8%) at approximately 30 degrees C. During the 2-h ride, they consumed either 2.4 L of a 7% carbohydrate (CHO) drink (HIGH) or 0.4 L of water (LOW) with sport gels to match for CHO content. After the 2-h ride and before the hill climb, drinking strategies influenced body mass (LOW -2.5 +/- 0.5% vs HIGH 0.3 +/- 0.4%; P < 0.001), HR (LOW 158 +/- 15 vs HIGH 146 +/- 15 bpm; P = 0.03), and rectal temperature (T(re): LOW 38.9 +/- 0.2 vs HIGH 38.3 +/- 0.2 degrees C; P = 0.001). Despite being approximately 1.9 kg lighter, time to exhaustion was significantly reduced by 28.6 +/- 13.8% in the LOW treatment (LOW 13.9 +/- 5.5 vs HIGH 19.5 +/- 6.0 min, P = 0.002), as was the power output for a fixed speed (LOW 308 +/- 28 vs HIGH 313 +/- 28 W, P = 0.003). At exhaustion, T(re) was higher in the LOW treatment (39.5 vs HIGH 39.1 degrees C; P < 0.001), yet peak HR, blood lactate, and glucose were similar. Exercise-induced dehydration in a warm environment is detrimental to laboratory cycling hill-climbing performance despite reducing the power output required for a given speed.

Muscular activity during uphill cycling: Effect of slope, posture, hand grip position and constrained bicycle lateral sways

Despite the wide use of surface electromyography (EMG) to study pedalling movement, there is a paucity of data concerning the muscular activity during uphill cycling, notably in standing posture. The aim of this study was to investigate the muscular activity of eight lower limb muscles and four upper limb muscles across various laboratory pedalling exercises which simulated uphill cycling conditions. Ten trained cyclists rode at 80% of their maximal aerobic power on an inclined motorised treadmill (4%, 7% and 10%) with using two pedalling postures (seated and standing). Two additional rides were made in standing at 4% slope to test the effect of the change of the hand grip position (from brake levers to the drops of the handlebar), and the influence of the lateral sways of the bicycle. For this last goal, the bicycle was fixed on a stationary ergometer to prevent the lean of the bicycle side-to-side. EMG was recorded from M. gluteus maximus (GM), M. vastus medialis (VM), M. rectus femoris (RF), M. biceps femoris (BF), M. semimembranosus (SM), M. gastrocnemius medialis (GAS), M. soleus (SOL), M. tibialis anterior (TA), M. biceps brachii (BB), M. triceps brachii (TB), M. rectus abdominis (RA) and M. erector spinae (ES). Unlike the slope, the change of pedalling posture in uphill cycling had a significant effect on the EMG activity, except for the three muscles crossing the ankle’s joint (GAS, SOL and TA). Intensity and duration of GM, VM, RF, BF, BB, TA, RA and ES activity were greater in standing while SM activity showed a slight decrease. In standing, global activity of upper limb was higher when the hand grip position was changed from brake level to the drops, but lower when the lateral sways of the bicycle were constrained. These results seem to be related to (1) the increase of the peak pedal force, (2) the change of the hip and knee joint moments, (3) the need to stabilize pelvic in reference with removing the saddle support, and (4) the shift of the mass centre forward.

Effet de la posture sur le choix de la fréquence de pédalage préférée en montée

Purpose. – The aim of this work was to study the effect of the posture on the preferred pedalling frequency during uphill cycling. Methods and results. – Ten trained cyclists performed two pedalling trials of three minutes at 80% of maximal aerobic power on a treadmill with a slope of 4%. Two postures (seated and standing pedalling) were studied in a randomized order. During the first minute of each trial, the subjects had to choose their preferred pedalling frequency with adjusting their gear and then kept this rate until the end of the trial. The preferred pedalling frequency was significantly ( P < 0.05) lower in standing (73 ± 7 rpm) than in seated pedalling (80 ± 9 rpm). Conclusion. – We suppose that cyclists choose a lower pedalling frequency during standing pedalling in order to generate greater peak pedal force and to decrease the number of lateral sways of bicycle and vertical elevations of pelvis, which increase energy cost.

Effects on the crank torque profile when changing pedalling cadence in level ground and uphill road cycling

Despite the importance of uphill cycling performance during cycling competitions, there is very little research investigating uphill cycling, particularly concerning field studies. The lack of research is partly due to the difficulties in obtaining data in the field. The aim of this study was to analyse the crank torque in road cycling on level and uphill using different pedalling cadences in the seated position. Seven male cyclists performed four tests in the seated position (1) on level ground at 80 and 100rpm, and (2) on uphill road cycling (9.25% grade) at 60 and 80rpm.The cyclists exercised for 1min at their maximal aerobic power. The bicycle was equipped with the SRM Training System (Schoberer, Germany) for the measurement of power output (W), torque (Nm), pedalling cadence (rpm), and cycling velocity (kmh−1). The most important finding of this study indicated that at maximal aerobic power the crank torque profile (relationship between torque and crank angle) varied substantially according to the pedalling cadence and with a minor effect according to the terrain. At the same power output and pedalling cadence (80rpm) the torque at a 45°crank angle tended (p<0.06) to be higher (+26%) during uphill cycling compared to level cycling. During uphill cycling at 60rpm the peak torque was increased by 42% compared with level ground cycling at 100rpm.When the pedalling cadence was modified, most of the variations in the crank torque profile were localised in the power output sector (45° to 135°).

Exercise intensity and load during uphill cycling in professional three-week races

Exercise intensity and load during uphill cycling in professional three-week races

Validity and Reliability of the Polar® S710 Mobile Cycling Powermeter

The purpose of this study was to determine the validity and reliability of a new mobile bike-powermeter, Polar S710, in laboratory and field conditions, against the SRM crankset. Eight trained subjects performed in a random order six uphill cycling trials of 6-min duration at three different intensities (60 %, 75 % and 90 % of peak power output [PPO]). In addition, 44 other cyclists performed in the laboratory three cycling bouts each of 5-min duration at three different pedal cadences (60, 90 and 110 rpm) at the same absolute intensity (approximately 150 W). Bias between the two devices was correlated (r = 0.79) with the mean power in field conditions; with the S710 reading higher (p < 0.001) by 7.4 +/- 5.1 % than the SRM in the range of power studied. In other words, the mean differences between the two devices increased as the exercise intensity increased. The mean power output obtained with S710 was significantly higher (p < 0.001) by 6.8 +/- 7.9 W (bias x divided-by random error = 1.042 x divided-by 1.049) than the power obtained with SRM in laboratory conditions. Ninety-five percent of the differences of power measured with the S710 ranged between 21.4 W above to 8.3 W below the SRM in laboratory conditions. Mean differences between the two devices increased as the pedalling cadence increased (0.6 +/- 3.8 %, 4.4 +/- 3.7 % and 7.8 +/- 4.4 % at cadence of 60, 90 and 110 rpm respectively). Coefficients of variation in mean power across the four field-based trials at 75 % PPO was 2.2 % and 1.9 % for S710 and SRM, respectively. In conclusion, the S710 recorded power outputs higher than the SRM system in both field and laboratory conditions. Pedalling cadence and exercise intensity influenced differences in mean power. These characteristics make S710 a useful device for recreational cyclists but not for elite cyclists or scientists who require a greater accuracy and validity. However, the limits of the present study (short-term duration testing; single tested variables as intensity, posture, pedalling cadence) require further investigation for generalizing the present results to extensive use in "real world" cycling.

Level ground and uphill cycling efficiency in seated and standing positions.

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). 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. 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). 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.

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.

Preferred pedalling cadence in professional cycling.

The aim of this investigation was to evaluate the preferred cycling cadence of professional riders during competition. We measured the cadence of seven professional cyclists (28 +/- 1 yr) during 3-wk road races (Giro d'Italia, Tour de France, and Vuelta a España) involving three main competition requirements: uphill cycling (high mountain passes of approximately 15 km, or HM); individual time trials of approximately 50 km on level ground (TT); and flat, long ( approximately 190 km) group stages (F). Heart rate (HR) data were also recorded as an indicator of exercise intensity during HM, TT, and F. Mean cadence was significantly lower (P < 0.01) during HM (71.0 +/- 1.4 rpm) than either F and TT (89.3 +/- 1.0 and 92.4 +/- 1.3 rpm, respectively). HR was similar during HM and TT (157 +/- 4 and 158 +/- 3 bpm) and in both cases higher (P < 0.01) than during F (124 +/- 2 bpm). During both F and TT, professional riders spontaneously adopt higher cadences (around 90 rpm) than those previously reported in the majority of laboratory studies as being the most economical. In contrast, during HM they seem to adopt a more economical pedalling rate (approximately 70 rpm), possibly as a result of the specific demands of this competition phase.

Physiological and performance characteristics of male professional road cyclists.

Male professional road cycling competitions last between 1 hour (e.g. the time trial in the World Championships) and 100 hours (e.g. the Tour de France). Although the final overall standings of a race are individual, it is undoubtedly a team sport. Professional road cyclists present with variable anthropometric values, but display impressive aerobic capacities [maximal power output 370 to 570 W, maximal oxygen uptake 4.4 to 6.4 L/min and power output at the onset of blood lactate accumulation (OBLA) 300 to 500 W]. Because of the variable anthropometric characteristics, 'specialists' have evolved within teams whose job is to perform in different terrain and racing conditions. In this respect, power outputs relative to mass exponents of 0.32 and 1 seem to be the best predictors of level ground and uphill cycling ability, respectively. However, time trial specialists have been shown to meet requirements to be top competitors in all terrain (level and uphill) and cycling conditions (individually and in a group). Based on competition heart rate measurements, time trials are raced under steady-state conditions, the shorter time trials being raced at average intensities close to OBLA (approximately 400 to 420 W), with the longer ones close to the individual lactate threshold (LT, approximately 370 to 390 W). Mass-start stages, on the other hand, are raced at low mean intensities (approximately 210 W for the flat stages, approximately 270 W for the high mountain stages), but are characterised by their intermittent nature, with cyclists spending on average 30 to 100 minutes at, and above LT, and 5 to 20 minutes at, and above OBLA.

Effects of front and dual suspension mountain bike systems on uphill cycling performance

The purpose of this study was to evaluate the effects of front suspension (FS) and dual suspension (DS) mountain bike designs on time-trial performance and physiological responses during uphill cycling on a paved- and off-road course. Six trained male cyclists (35.6 +/- 9 yr, 76.9 +/- 8.8 kg, VO2 peak 58.4 +/- 5.6 mL x kg(-1) x min-1)) were timed using both suspension systems on an uphill paved course (1.62 km, 183-m elevation gain) and an uphill off-road course (1.38 km, 123-m elevation gain). During the field trials, VO2 was monitored continuously with a KB1-C portable gas analyzer, and power output with an SRM training system. On the paved course, total ride time on FS (10.4 +/- 0.7 min) and DS (10.4 +/- 0.8 min) was not different (P > 0.05). Similarly, total ride time on the off-road course was not significantly different on the FS bike (8.3 +/- 0.7 min) versus the DS bike (8.4 +/- 1.1 min). For each of the course conditions, there was no significant difference between FS and DS in average minute-by-minute VO2, whether expressed in absolute (ABS; L x min(-1)) or relative (REL; mL x [kg body wt +/- kg bike wt(-1)] x min(-1) values. Average power output (W) was significantly lower for ABS FS versus DS (266.1 +/- 61.6 W vs 341.9 +/- 61.1 W, P < 0.001) and REL FS versus DS (2.90 +/- 0.55 W x kg(-1) vs 3.65 +/- 0.53 W x kg(-1), P < 0.001) during the off-road trials. Power output on the paved course was also significantly different for ABS FS versus DS (266.6 +/- 52 W vs 345.4 +/- 53.4 W, P < 0.001) and REL FS versus DS (2.99 +/- 0.55 W x kg(-1) vs 3.84 +/- 0.54 W x kg(-1), P < 0.001). We conclude that despite significant differences in power output between FS and DS mountain bike systems during uphill cycling, these differences do not translate into significant differences in oxygen cost or time to complete either a paved- or off-road course.

Level ground and uphill cycling ability in professional road cycling.

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