Purpose: To monitor training-related changes in gross efficiency (GE) over the course of a competitive cycling season.
Methods: Fourteen trained cyclists (mean ± SD: 34 + 8 yr, 74.3 ± 7.4 kg, Wmax = 406 ± 43 W, V˙O2max = 59.5 ± 3.8 mL· kg-1·min-1) with at least 3 yr competitive experience completed five laboratory tests during a competitive cycling season. The tests measured lactate threshold (LT), onset of blood lactate accumulation (OBLA), maximal oxygen uptake (V˙O2max), maximal minute power (Wmax), and GE. The data were analyzed using repeated-measures ANOVA and Pearson's product-moment correlation coefficient.
Results: GE changed significantly over the course of the competitive cycling season (P < 0.05), increasing over the precompetition phase of the season (19.6% vs 20.6%; P < 0.05). GE was maintained during the main competitive phase of the season (20.6% vs 20.3%; P > 0.05) and then decreased during the postcompetitive phase to 19.4% (P < 0.05). The precompetition changes in GE were related to the total time spent training and the time spent above OBLA intensity (r = 0.84 and 0.80, respectively). Riders who spent the most time training between LT and OBLA intensities (r = 0.87; P < 0.05) were better able to maintain GE. A significant inverse relationship was also identified between the changes in GE and the percentage change in training below LT over the competitive phase of the season.
Conclusion: GE changes over the course of a competitive cycling season and is related to the volume and intensity of training conducted.
Medicine & Science in Sports & Exercise:Volume 41(4)April 2009pp 904-911 Velocity-Specific Fatigue: Quantifying Fatigue during Variable Velocity Cycling
GARDNER, A. SCOTT1; MARTIN, DAVID T.2; JENKINS, DAVID G.3; DYER, IAIN4; VAN EIDEN, JAN4; BARRAS, MARTIN5; MARTIN, JAMES C.6
Previous investigators have quantified fatigue during short maximal cycling trials (∼30 s) by calculating a fatigue index. Other investigators have reported a curvilinear power-pedaling rate relationship during short fatigue-free maximal cycling trials (<6 s). During maximal trials, pedaling rates may change with fatigue. Quantification of fatigue using fatigue index is therefore complicated by the power-pedaling rate relationship.
Purpose: The purpose of this study was to quantify fatigue while accounting for the effects of pedaling rate on power.
Methods: Power and pedaling rate were recorded during Union Cycliste Internationale sanctioned 200-m time trials by eight male (height = 181.5 ± 4.3 cm, mass = 87.0 ± 8.0 kg) world-class sprint cyclists with SRM power meters and fixed-gear track bicycles. Data from the initial portion of maximal acceleration were used to establish maximal power-pedaling rate relationships. Fatigue was quantified three ways: 1) traditional fatigue index, 2) fatigue index modified to account for the power-pedaling rate relationship (net fatigue index), and 3) work deficit, the difference between actual work done and work that might have been accomplished without fatigue.
Results: Fatigue index (55.4% ± 6.4%) was significantly greater than net fatigue index (41.0% ± 7.9%, P < 0.001), indicating that the power-pedaling rate relationship accounted for 14.3% ± 7% of the traditional fatigue index value. Work deficit (23.3% ± 6%) was significantly less than either measure of fatigue (P < 0.001).
Conclusion: Net fatigue index and work deficit account for the power-pedaling rate relation and therefore more precisely quantify fatigue during variable velocity cycling. These measures can be used to compare fatigue during different fatigue protocols, including world-class sprint cycling competition. Precise quantification of fatigue during elite cycling competition may improve evaluation of training status, gear ratio selection, and fatigue resistance.
Determinants of “optimal” cadence during cycling Authors: Les Ansley a; Patrick Cangley b Published in: journal European Journal of Sport Science, Volume 9, Issue 2 March 2009 , pages 61 - 85
Abstract Cadence is one of the only variables cyclists can adjust to manage their performance and fatigue during an event. Not surprisingly, cadence has received a great deal of attention from the scientific community in an effort to identify the cadence that optimizes power output while minimizing the fatigue that is incurred. The literature appears to present conflicting results with little consensus as regards the optimal pedalling cadence. This is in large part due to the inconsistent definition of the term “optimal” cadence, which has been used to describe energetic cost, muscular stress, and perception of effort. The issue is further confounded by the workload-dependent nature of the “optimal” cadence - that is, at higher power outputs, the optimized cadence is different from that at lower power outputs. Although the optimal cadence is different for energetic, muscular, and perceptual definitions, the curves that describe the effect of changes in cadence on these variables consistently exhibit a J-shaped response. This suggests that there is an underlying principle that is common to each of the definitions. Indeed, it would appear that the response of both the cardio-respiratory system (energetic cost) and the muscular system (muscular stress) is determined by the types of muscle motor units that are recruited during the exercise. Furthermore, although part of the response may be due to the inherent differences in the characteristics between the different motor units, the absolute contraction velocity relative to fibre type optimum may be of greater significance. Even when the power output is increased, the shape of the response curves to changes in cadence remains constant, although the nadir of the curve does shift to the right for increasing power outputs. We propose that the point at which the energetic vs. power and the muscular stress vs. power curves intercept is defined by the cadence at which the perceived effort is minimized (i.e. the preferred cadence). However, cadence fluctuations occur under field conditions that are unrelated to physiological factors and, therefore, the ability to identify an “optimal” cadence is limited to the laboratory environment and specific field conditions.
Medicine & Science in Sports & Exercise:Volume 41(4)April 2009pp 898-903 β-Alanine Improves Sprint Performance in Endurance Cycling
Purpose: Recent research has shown that chronic dietary β-alanine (βALA) supplementation increases muscle carnosine content, which is associated with better performance in short (1-2 min) maximal exercise. Success in endurance competitions often depends on a final sprint. However, whether βALA can be ergogenic in sprint performance at the end of an endurance competition is at present unknown. Therefore, we investigated the effect of 8-wk βALA administration in moderately to well-trained cyclists on sprint performance at the end of a simulated endurance cycling race.
Methods: A double-blind study was performed, which consisted of two experimental test sessions interspersed by an 8-wk βALA (2-4 g·d-1; n = 9) or matched placebo (PL; n = 8) supplementation period. In the pretesting and the posttesting, subjects performed a 10-min time trial and a 30-s isokinetic sprint (100 rpm) after a 110-min simulated cycling race. Capillary blood samples were collected for determination of blood lactate concentration and pH.
Results: Mean power output during the time trial was approximately 300 W and was similar between PL and βALA during either the pretesting or the posttesting. However, compared with PL, during the final sprint after the time trial, βALA on average increased peak power output by 11.4% (95% confidence interval = +7.8 to +14.9%, P = 0.0001), whereas mean power output increased by 5.0% (95% confidence interval = +2.0 to +8.1%, P = 0.005). Blood lactate and pH values were similar between groups at any time.
Conclusion: Oral βALA supplementation can significantly enhance sprint performance at the end of an exhaustive endurance exercise bout.
British Journal of Sports Medicine 2009;43:180-185 Workload demands in professional multi-stage cycling races of varying duration
J A Rodríguez-Marroyo1, J García-López1, C-É Juneau2 and J G Villa1
Objetive: To analyse and compare the workload exerted by professional cyclists in 5-day, 8-day and 21-day stage races (5-SR, 8-SR, 21-SR).
Methods: The study subjects were 30 professional cyclists competing in 10 5-SR, 5 8-SR and 5 21-SR. Heart rate (HR) was measured during the races and categorised into three intensity zones: Z1 (below the ventilatory threshold (VT)), Z2 (between VT and the respiratory compensation threshold (RCT)) and Z3 (above RCT). The training impulse (TRIMP) was calculated by multiplying the sum of the time spent in each zone by 1, 2 and 3, respectively. Monotony (average TRIMP/SD) and strain (total TRIMPxmonotony) were also calculated for each race type.
Results: The average time spent in Z3 during each stage was significantly (p<0.05) higher for 5-SR (~31 min) and 8-SR (~28 min) than for 21-SR (~14 min). Daily TRIMP values in 5-SR (~400) and 8-SR (~395) were also higher than in 21-SR (~370). Monotony was similar across races (~3) but strain was about three times higher for 21-SR than for 5-SR and 8-SR.
Conclusions: The cyclists’ effort by stage was less for 21-SR than for 5-SR and 8-SR. Competition strain and monotony accumulated during longer races influence the choice of strategies adopted by cyclists. It is likely that the intensity of each stage is modulated by total race duration, with longer races averaging the lowest daily workload.
An Ultra-cycling Race Leads to no Decrease in Skeletal Muscle Mass
B. Knechtle1,2, A. Wirth1, P. Knechtle1, T. Rosemann2
Ultra-endurance races lead to an enormous energy deficit, and a decrease in body mass in the form of fat mass as well as skeletal muscle mass can be found. The decrease in skeletal muscle mass has been demonstrated in ultra-runners. We investigated therefore, in an ultra-cycling race, whether ultra-cyclists also suffered a decrease in body mass and whether we could find changes in skeletal muscle mass and/or fat mass. The anthropometric method was used to determine body mass, skeletal muscle mass and fat mass in 28 male Caucasian, non-professional, ultra-cyclists before and after a 600 km ultra-cycling race. In order to quantify hydration status, we measured total body water, haematocrit, plasma sodium and urinary specific gravity. In addition, plasma urea was determined as a marker of protein catabolism. Body mass as well as fat mass decreased highly significantly (p<0.01) whereas skeletal muscle mass did not change (p>0.05). The post race minus pre race difference (Δ) in body mass was associated with Δ fat mass (p<0.05). Urea increased highly significantly (p<0.01); however Δ urea was not associated with Δ skeletal muscle mass. We concluded that ultra-cycling in contrast to ultra-running leads to no reduction in skeletal muscle mass.
Influence of Starting Strategy on Cycling Time Trial Performance in the Heat
C. R. Abbiss1,2, J. J. Peiffer1, B. A. Wall1, D. T. Martin2, P. B. Laursen1
The purpose of this study was to determine the influence of starting strategy on time trial performance in the heat. Eleven endurance trained male cyclists (30±5 years, 79.5±4.6 kg, V˙O2max 58.5±5.0 ml.kg.−1 min−1) performed four 20-km time trials in the heat (32.7±0.7°C and 55% relative humidity). The first time trial was completed at a self-selected pace (SPTT). During the following time trials, subjects performed the initial 2.5-km at power outputs 10% above (10% ATT), 10% below (10% BTT) or equal (ETT) to that of the average power during the initial 2.5-km of the self-selected trial; the remaining 17.5-km was self-paced. Throughout each time trial, power output, rectal temperature, skin temperature, heat storage, pain intensity and thermal sensation were taken. Despite significantly (P<0.05) greater power outputs for 10% BTT (273±45W) compared with the ETT (267±48W) and 10% ATT (265±41W) during the final 17.5-km, overall 20-km performance time was not significantly different amongst trials. There were no differences in any of the other measured variables between trials. These data show that varying starting power by ±10% did not affect 20 km time trial performance in the heat.
Changes in heart rate recovery after high-intensity training in well-trained cyclists Journal European Journal of Applied Physiology ISSN 1439-6319 (Print) 1439-6327 (Online) Issue Volume 105, Number 5 / March, 2009
Abstract Heart rate recovery (HRR) after submaximal exercise improves after training. However, it is unknown if this also occurs in already well-trained cyclists. Therefore, 14 well-trained cyclists (VO2max 60.3 ± 7.2 ml kg−1 min−1; relative peak power output 5.2 ± 0.6 W kg−1) participated in a high-intensity training programme (eight sessions in 4 weeks). Before and after high-intensity training, performance was assessed with a peak power output test including respiratory gas analysis (VO2max) and a 40-km time trial. HRR was measured after every high-intensity training session and 40-km time trial. After the training period peak power output, expressed as W kg−1, improved by 4.7% (P = 0.000010) and 40-km time trial improved by 2.2% (P = 0.000007), whereas there was no change in VO2max (P = 0.066571). Both HRR after the high intensity training sessions (7 ± 6 beats; P = 0.001302) and HRR after the 40-km time trials (6 ± 3 beats; P = 0.023101) improved significantly after the training period. Good relationships were found between improvements in HRR40-km and improvements in peak power output (r = 0.73; P < 0.0001) and 40-km time trial time (r = 0.96; P < 0.0001). In conclusion, HRR is a sensitive marker which tracks changes in training status in already well-trained cyclists and has the potential to have an important role in monitoring and prescribing training.
Time Trial Exertion Traits of Cycling's Grand Tours
C. P. Earnest1, C. Foster2, J. Hoyos3, C. A. Muniesa4, A. Santalla5, A. Lucia4
We examined 26 professional riders during time trial (TT) competitions of the Grand Tours of cycling (Tour de France and Vuelta Espana; 1997-2003) for the exertional characteristics of contending vs. non-contending (i.e., support) riders. We categorized HR time during TT into training impulse (TRIMP) defined from seasonal VO2max testing [Phase I (<ventilatory threshold (VT≈64% VO2max); Phase II (VT - respiratory compensation threshold, ≈83% VO2max); Phase III >RCP]. Races were: Short TT (<15 km; 8.9±2.9 km); Individual TT (>15 km; 48.12±8.7 km); Uphill TT (20.0±8.7 km) and Team TT (44.1±20.9 km). We observed statistically significant event-by-contender interactions for all TT (all, P<0.0001) except the short TT. During uphill TT, contenders exerted fewer total TRIMP (P<0.01), more Zone 3 TRIMP (P<0.05), and fewer Zone 2 TRIMP (P<0.01) vs. non-contenders. For individual TT, contenders accumulated more Total and Zone 3 TRIMP vs. non-contenders (all, P<0.05). Interestingly, during the team TT, contenders accumulated more Zone 3, and fewer Zone 2 TRIMP (all, P<0.05), despite having the opportunity to draft behind other riders while in paceline race formation. During TT events, contending riders compete at a level of exertion corresponding to a higher metabolic demand during the uphill TT, individual TT and team TT.
P. Debraux1, W. Bertucci1, A. V. Manolova1, S. Rogier1, A. Lodini1
The purpose of this study was to test the validity and reliability of a new method to estimate the projected frontal area of the body during cycling. To illustrate the use of this method in another cycling speciality (i.e. mountain bike), the NM data were coupled with a powermeter measurement to determine the projected frontal area and the coefficient of drag in actual conditions. Nine male cyclists had their frontal area determined from digital photographic images in a laboratory while seated on their bicycles in two positions:Upright Position (UP) and Traditional Aerodynamic Position (TAP). For each position, the projected frontal area for the body of the cyclist as well as the cyclist and his bicycle were measured using a new method with computer aided-design software, the method of weighing photographs and the digitizing method. The results showed that no significant difference existed between the new method and the method of weighing photographs in the measurement of the frontal area of the body of cyclists in UP (p=0.43) and TAP (p=0.14), or between the new method and the digitizing method in measurement of the frontal area for the cyclist and his bicycle in UP (p=0.12) and TAP (p=0.31). The coefficients of variation of the new method and the method of weighing photographs were 0.1% and 1.26%, respectively. In conclusion, the new method was valid and reliable in estimating the frontal area compared with the method of weighing photographs and the digitizing method.
Muscle Efficiency Improves over Time in World-Class Cyclists.
Medicine & Science in Sports & Exercise. 41(5):1096-1101, May 2009. SANTALLA, ALFREDO 1; NARANJO, JOSE 1,4; TERRADOS, NICOLAS 2,3 Abstract: Purpose: To determine the change in muscular efficiency in world-class professional cyclists during years of training/competition.
Methods: Twelve male world-class professional road cyclists (mean +/- SD: age = 22.6 +/- 3.8 yr and V[spacing dot above]O2max = 75.5 +/- 3.3 mL[middle dot]kg-1[middle dot]min-1) performed an incremental test (starting at 100 W with workload increases of 50 W every 4-min interval until volitional exhaustion) before and after a five-season period. Delta efficiency (DE) was calculated from 100 W to that power output (PO) in which the RER was 1.
Results: DE increased (P < 0.01) from 23.61 +/- 2.78% to 26.97 +/- 3.7% from the first to the fifth year, whereas V[spacing dot above]O2max showed no significant increase. A significant inverse correlation (r = -0.620; P = 0.032) between DE and V[spacing dot above]O2max (mL[middle dot]kg-1[middle dot]min-1) was found in the fifth year, whereas no significant correlation between these variables was found in the first year. A significant inverse correlation (r = -0.63; P = 0.029) was found between the increase percentage in DE ([DELTA]DE) and V[spacing dot above]O2max (mL[middle dot]kg-1[middle dot]min-1) in the fifth year, whereas no significant correlation was found between these variables in the first year.
Conclusion: The results show an increase in DE in world-class professional cyclists during a five-season training/competition period, without significant variations in V[spacing dot above]O2max. The results also suggest that the increase in DE could be a possible way for performance compensation, especially in those subjects with lower V[spacing dot above]O2max.