Physiological response to professional road cycling: climbers vs. time trialists

The purpose of this study was to identify possible physiological differences between professional cyclists who show best performance in hill climbing ("climbers") and those who excel in time trials ("time trialists"). To this end, professional, top-level climbers (C; n=8; age 26 +/- 1yr; height 176.0 +/- 2.0cm; body mass 63.6 +/- 2.2 kg) and time trialists (TT; n=6; 27 +/- 1yr; height 181.6 +/- 1.7 cm; body mass 72.3 +/- 2.3 kg) were required to perform two laboratory exercise tests on a cycle ergometer: a) a maximal exercise test (ramp protocol) and b) a constant load test of 20-min duration at approximately 80% of VO2max. Capillary blood lactate concentration and several gas exchange variables were measured during the maximal tests while determinations made during the submaximal tests also included: pH and bicarbonate concentration [HCO3-] in venous blood, and electromyographic (EMG) recordings from the vastus lateralis muscle to estimate root mean square voltage (rms-EMG) and mean power frequency (MPF). Both the maximal lactate concentration in capillary blood and VO2max were greater (p<0.05) in C than in TT (6.6 +/- 0.9 mM vs. 5.0 +/- 0.4 mM, respectively, and 78.4 +/- 3.2 ml x kg(-1) x min(-1) vs. 70.5 +/- 2.4 ml x kg(-1) x min(-1), respectively). Higher mean venous blood pH and [HCO3-] (p<0.05), rms-EMG (p<0.01) and MPF (p<0.05 at 10 and 15min of exercise and p < 0.01 at 5 and 20 min) were recorded in C throughout the submaximal tests. Our findings suggest that in top-level professional cyclists, climbing performance is mainly related to physiological factors (VO2max normalized for body mass, anaerobicl buffer capacity, motor unit recruitment) whereas time trialists tend to achieve greater absolute power outputs. It would also seem that other "technical" requirements of the sport (i. e. pedaling efficiency probably related to biomechanical factors etc.) may be associated with successful time trial performance.     

Physiological differences of elite and professional road cyclists related to competition level and rider specialization

AIM: The aim of this investigation was to study the physiological response to laboratory tests in elite and professional cyclists, and to relate it to the level at which riders compete and their specialization. METHODS: A total of 71 cyclists were divided into two groups, elite and professional, and were assessed for physical measurements, a maximal graded test and a 30 s all-out test, both performed on a cycle ergometer. The sample included 24 uphill riders (UR), 32 flat terrain riders (FTR), 11 all terrain riders (ATR) and 4 sprinters (SP). RESULTS: Professional riders showed significantly higher gross mechanical efficiency (GME) than their elite counterparts (25.6+/-2.6 vs 24.4+/-2%), but otherwise no other physiological differences emerged from the comparison between these two groups. However, many differences exist as a function of rider specialization, especially between UR and FTR. Compared with FTR, UR showed a higher VO2max (78.2+/-5.5 vs 72.6+/-6.5 mL x min(-1) x kg(-1)) and a lower maximal aerobic power (438.5+/-40.8 vs 465.3+/-36.2 W). From the 30 s all-out test, SP presents the highest maximal power (P < 0.05) and maximal velocity (P < 0.05) compared with all the other groups. CONCLUSIONS: The results for GME indicate a better efficiency for professional riders and suggest the importance of technical aspects related to movement pattern in cycling. The sensitivity of the maximal graded test and the 30 s all-out test did not allowed other differentiations between elite and professional cyclists.     

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.     

Heart rate response to professional road cycling: the Tour de France.

The aim of the present investigation was to evaluate the heart rate response of 8 professional cyclists (26+/-3 yr; 68.9+/-5.2 kg; V02max: 74.0+/-5.8 ml x kg(-1) x min(-1)) during the 3-week Tour de France as an indicator of exercise intensity. Subjects wore a heart rate telemeter during 22 competition stages and recorded data were analysed using computer software. Two reference heart rates (corresponding to the first and second ventilatory thresholds or VT1 and VT2) were used to establish three levels of exercise intensity defined as phases I (VT2) is substantially lower than that of light, aerobic exercise (相似文献   

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.     

Barriers to achieving commercial success for diagnostic and therapeutic radiopharmaceuticals

The concluding session of this workshop focused on barriers that might be impeding the successful transition of radiopharmaceuticals from research tools to diagnostics and therapeutics that reach commercial success. Some lessons can be learned by reviewing the technology adoption life cycle as described by Geoffrey A. Moore (Moore, GA. Crossing the chasm. New York: HarperCollins, 2002). Additionally, a review of highly successful radiopharmaceuticals suggests that achieving commercial success may require advocacy by other interested groups.     

Exercise intensity and load during mass-start stage races in professional road cycling

PURPOSE: To evaluate exercise intensity and load during mass-start stages in professional road cycling, using competition heart rate (HR) recordings. METHODS: Seventeen world-class cyclists performed an incremental laboratory test during which maximal power output (Wmax), maximal HR (HRmax), onset of blood lactate accumulation (OBLA), lactate threshold (LT), and a HR-power output relationship were assessed. An OBLAZONE (HROBLA +/- 3 beats.min-1) and an LTZONE (HRLT +/- 3 beats.min-1) were described. HR was monitored during 125 flat (< 13 km uphill, < 800-m altitude change; FLAT), 99 semi-mountainous (13-35 km uphill, 800- to 2000-m altitude change; SEMO), and 86 high-mountain (> 35 km uphill, > 2000-m altitude change; HIMO) stages. Each cyclist's competition power output was estimated from competition HR and individual HR-power output relationships. Competition training impulse (TRIMP) values and time spent at "easy," "moderate," and "hard" zones were estimated from HR and race duration. RESULTS: Average %HRmax were 61 +/- 5%, 58 +/- 6%, and 51 +/- 7% in HIMO, SEMO, and FLAT stages, respectively, and estimated average power outputs were 246 +/- 44, 234 +/- 43, and 192 +/- 45 W. Competition HR values relative to HROBLA and HRLT were, respectively, 69 +/- 6, 79 +/- 9% in HIMO; 65 +/- 7, 74 +/- 11% in SEMO; and 57 +/- 8, 65 +/- 10% in FLAT stages. The amount of TRIMP in HIMO, SEMO, and FLAT stages were, respectively, 215 +/- 38, 172 +/- 31, and 156 +/- 31. Percentage time spent in the "moderate" and "hard" zones was highest in HIMO (22 +/- 14, 5 +/- 6%) followed by SEMO (15 +/- 13, 5 +/- 5%) and FLAT (9 +/- 7, 2 +/- 2%) stages. CONCLUSIONS: %HRmax, time distribution around HROBLA and HRLT, TRIMP, and load zones reflected the physiological demands of different mass-start cycling stage categories. The knowledge of these demands could be useful for planning precompetition training strategies.     

The registration and scheduling processes

The entry of patient information via a computer registration system eliminates the manual and repetitive handling of patient information in many different operations. Present scheduling systems range to the very sophisticated that not only smooth peaks and valleys but also eliminate examination conflicts and unnecessary, similar, and duplicate examinations to increase departmental productivity using the existing radiographic rooms and technologic staff.     

Decoupled automated rotational and translational registration for functional MRI time series data: The dart registration algorithm

A rapid, in-plane image registration algorithm that accurately estimates and corrects for rotational and translational motion is described. This automated, one-pass method achieves its computational efficiency by decoupling the estimation of rotation and translation, allowing the application of rapid cross-correlation and cross-spectrum techniques for the determination of displacement parameters. k-space regridding and modulation techniques are used for image correction as alternatives to linear interpolation. The performance of this method was analyzed with simulations and echo-planar image data from both phantoms and human subjects. The processing time for image registration on a Hewlett-Packard 735/125 is 7.5 s for a 128 × 128 pixel image and 1.7 s for a 64 × 64 pixel image. Imaging phantom data demonstrate the accuracy of the method (mean rotational error, ?0.09°; standard deviation = 0.17°; range, ?0.44° to + 0.31°; mean translational error = ?0.035 pixels; standard deviation = 0.054 pixels; range, ?0.16 to + 0.06 pixels). Registered human functional imaging data demonstrate a significant reduction in motion artifacts such as linear trends in pixel time series and activation artifacts due to stimulus-correlated motion. The advantages of this technique are its noniterative one-pass nature, the reduction in image degradation as compared to previous methods, and the speed of computation.     

The team effect on doping in professional male road cycling (2005‐2016)

This article questions organizations’ (clubs, teams, etc) responsibility in doping use from the case of anti‐doping rules violations (ADRVs) sanctioned by the Union Cycliste Internationale in professional cycling. We built a database with 271 caught riders among 10 551 professional riders employed from 2005 to 2016 in the three first world divisions. We developed a time‐discrete event history model with a multilevel perspective to consider if the ADRV is related to the characteristic of a rider's career path (level 1) and/or the team by which the rider is employed (level 2). Our results confirm two hypotheses: Beginning a career before 2005 or after the age of 22 increased the risk of being caught. Each additional year in the pack increased the risk, despite the fact that a sanctioned rider's career duration average is 7.8 years (3.9 for the others). These caught riders have experienced a more tumultuous career with team changes and an interrupted path. A 2.45 Median Odds Ratio led us to assert a team effect on ADRV. By a team residual effect calculation, we identify 17 teams with a significant effect within the 129 that experienced an ADRV. Our results allow us to emphasize that to understand doping we must take into account work and employment condition, as well as team's organization. This approach completes the dominant “methodological individualism” perspective that considers athletes as analytical units and provides guidelines to the anti‐doping bodies that focus their action on individuals.     

The principal axes transformation--a method for image registration

We have developed a computational technique suitable for registration of sets of image data covering the whole brain volume which are translated and rotated with respect to one another. The same computational method may be used to register pairs of tomographic brain images which are rotated and translated in the transverse section plane. The technique is based on the classical theory of rigid bodies, employing as its basis the principal axes transformation. The performance of the method was studied by simulation and with image data from PET, XCT, and MRI. It was found that random errors in determining the brain contour are well tolerated. Progressively coarser axial sampling of data sets led to some degradation, but acceptable performance was obtained with axial sampling distances up to 10 mm. Given adequate digital sampling of the object volume, we conclude that registration by the principal axes transformation can be accomplished with typical errors in the range of approximately 1 mm. The advantages of the technique are simplicity and speed of computation.     

Lactic acidosis, potassium, and the heart rate deflection point in professional road cyclists

OBJECTIVE: To determine the influence of lactic acidosis, the Bohr effect, and exercise induced hyperkalaemia on the occurrence of the heart rate deflection point (HRDP) in elite (professional) cyclists. METHODS: Sixteen professional male road cyclists (mean (SD) age 26 (1) years) performed a ramp test on a cycle ergometer (workload increases of 5 W/12 s, averaging 25 W/min). Heart rate (HR), gas exchange parameters, and blood variables (lactate, pH, P(50) of the oxyhaemoglobin dissociation curve, and K(+)) were measured during the tests. RESULTS: A HRDP was shown in 56% of subjects at about 88% of their maximal HR (HRDP group; n = 9) but was linear in the rest (No-HRDP group; n = 7). In the HRDP group, the slope of the HR-workload regression line above the HRDP correlated inversely with levels of K(+) at the maximal power output (r = -0.67; p<0.05). CONCLUSIONS: The HRDP phenomenon is associated, at least partly, with exercise induced hyperkalaemia.