Cadence-power-relationship during decisive mountain ascents at the Tour de France

The aim of the study was to report the relationship between cadence and power developed by professional cyclists during high mountain ascents of the Tour de France. From the 10 cyclists (30 +/- 4 years, 178 +/- 8 cm, 69 +/- 6 kg) involved in the study, 108 ascents were recorded and analyzed using a mobile power measurement device (SRM Training Systems, Jülich, Germany). Based on topographic characteristics, the ascents were categorized into 1st and Hors Category (HC) climbs. During the ascents of the 1st Category climbs, power output averaged 312 +/- 43 W (4.5 +/- 0.6 W/kg) with a mean cadence of 73 +/- 6 rpm and a mean duration of 37 : 41 +/- 16 : 16 min. Power output averaged 294 +/- 36 W (4.3 +/- 0.6 W/kg) at a mean cadence of 70 +/- 6 rpm during 57 : 40 +/- 10 : 32 min on HC climbs. The maximal mean power for long durations (1800 s) showed a mean power output of 327 W and 346 W for the 1st and HC climbs, respectively. The evaluation of the cadence-power output and the distance per pedaling cycle-power output relationship shows that high power outputs are mainly yielded by higher pedaling cadences and higher gears.     

The Tour de France: a physiological review

On 5 July 2003, the Tour de France (TDF) has celebrated 100th running. Instead of a chimney sweep competing during his free time (as in 1903), the recent winner is a highly trained, professional cyclist whose entire life-style has been dedicated to reach his pinnacle during this event. The TDF has been held successfully for 100 years, but the application of the physiologic sciences to the sport is a relatively recent phenomenon. Although some historical reports help to understand the unique physiological characteristics of this race, scientific studies were not available in Sports Science/Applied Physiology journals until the 1990s. The aim of this article is to review the history of the TDF. Special emphasis is placed on the last decade where classic physiology has been integrated into applied scientific cycling data.     

Increased average longevity among the "Tour de France" cyclists

It is widely held among the general population and even among health professionals that moderate exercise is a healthy practice but long term high intensity exercise is not. The specific amount of physical activity necessary for good health remains unclear. To date, longevity studies of elite athletes have been relatively sparse and the results are somewhat conflicting. The Tour de France is among the most gruelling sport events in the world, during which highly trained professional cyclists undertake high intensity exercise for a full 3 weeks. Consequently we set out to determine the longevity of the participants in the Tour de France, compared with that of the general population. We studied the longevity of 834 cyclists from France (n=465), Italy (n=196) and Belgium (n=173) who rode the Tour de France between the years 1930 and 1964. Dates of birth and death of the cyclists were obtained on December 31 (st) 2007. We calculated the percentage of survivors for each age and compared them with the values for the pooled general population of France, Italy and Belgium for the appropriate age cohorts. We found a very significant increase in average longevity (17%) of the cyclists when compared with the general population. The age at which 50% of the general population died was 73.5 vs. 81.5 years in Tour de France participants. Our major finding is that repeated very intense exercise prolongs life span in well trained practitioners. Our findings underpin the importance of exercising without the fear that becoming exhausted might be bad for one's health.     

Haematological analysis conducted at the departure of the Tour de France 2001

Since the introduction of blood analysis performed before major cycling events in 1997, there have been discussions concerning the quality of the results. The aim of our study therefore was to measure blood samples and compare the results obtained on the field with those obtained in the laboratory. For this it was necessary to have blood samples analysed with different instruments to determine the exactness of the results and evaluate the performances of these instruments in order to validate the haematological testing used to reveal athletes abusing recombinant erythropoietin. We report on the haematological analysis of 177 professional cyclists who took part in the Tour de France 2001. All the blood samples were withdrawn in the morning between 7 and 9 am in Dunkerque (France) and were analysed immediately with a transportable analyser. Then the samples were flown to Lausanne (Switzerland) and were reanalysed in two independent ISO 17 025 accredited laboratories with three different analysers. The results confirmed that the most effective haematological follow-up should be performed under standardized pre-analytical conditions and with identical analysers of the same manufacturer to avoid too many variations notably on the haematocrit level and the reticulocyte count. Furthermore, this study suggests that analyses performed on the site are good and could enable the federations to perform a urinary test to detect rhEPO abuse right after the blood analysis. This time saving is essential to fight efficiently recombinant erythropoietin doping, because the half life of the hormone is very short.     

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   

输出功率可调的激光输出光纤耦合系统

以不同波长、不同功率密度激光照射各类细胞，选择最适宜的波长和功率密度具有实验与临床意义。为适应该项研究的需要，设计了会聚透镜与光纤耦合器的距离可以精确调节的耦合系统。它与多种激光器组合，可得到输出功率可调的多种波长的实验条件。使用方便，满足基础研究的要求     

Hormone levels of world class cyclists during the Tour of Spain stage race.

Objectives—To evaluate the hormonal response to strenuous endurance exercise performed by elite athletes. Methods—Nine professional cyclists (mean (SD) age 28 (1) years; mean (SD) VO₂MAX 75.3 (2.3) ml/kg/min) who participated in a three week tour race (Vuelta a España 1999) were selected as subjects. Morning urinary levels of 6-sulphatoxymelatonin (aMT6s) and morning serum levels of testosterone, follicle stimulating (FSH), luteinising hormone (LH), and cortisol were measured in each subject at t₀ (before the competition), t₁ (end of first week), t₂ (end of second week), and t₃ (end of third week). Urine samples of aMT6s were also evaluated in the evening at t₀, t₁, t₂, and t₃. Results—Mean urinary aMT6s levels had increased significantly (p<0.01) during the day after each stage (1091 (33) v 683 (68) ng/ml at t₁; 955 (19) v 473 (53) ng/ml at t₂; 647 (61) v 337 (47) ng/ml at t₃). Both morning and evening aMT6s levels decreased significantly during the study. A similar pattern was observed for morning serum levels of cortisol and testosterone. Conclusions—The results suggest that the basal activity of the pineal gland, adrenal glands, and testis may be decreased after consecutive days of intense, long term exercise. Key Words: melatonin; gonadotrophins; testosterone; cortisol; endurance exercise     

Relation between physical exertion and heart rate variability characteristics in professional cyclists during the Tour of Spain

Background: Continued exposure to prolonged periods of intense exercise may unfavourably alter neuroendocrine, neuromuscular, and cardiovascular function.

Objective: To examine the relation between quantifiable levels of exertion (TRIMPS) and resting heart rate (HR) and resting supine heart rate variability (HRV) in professional cyclists during a three week stage race.

Method: Eight professional male cyclists (mean (SEM) age 27 (1) years, body mass 65.5 (2.3) kg, and maximum rate of oxygen consumption (V^·O₂MAX) 75.6 (2.2) ml/kg/min) riding in the 2001 Vuelta a España were examined for resting HR and HRV on the mornings of day 0 (baseline), day 10 (first rest day), and day 17 (second rest day). The rest days followed stages 1–9 and 10–15 respectively. HR was recorded during each race stage, and total HR time was categorised into a modified, three phase TRIMPS schema. These phases were based on standardised physiological laboratory values obtained during previous V^·O₂MAX testing, where HR time in each phase (phase I = light intensity and less than ventilatory threshold (VT; ~70% V^·O₂MAX); phase II = moderate intensity between VT and respiratory compensation point (RCP; ~90% V^·O₂MAX); phase III = high intensity (>RCP)) was multiplied by exertional factors of 1, 2, and 3 respectively.

Results: Multivariate analysis of variance showed that total TRIMPS for race stages 1–9 (2466 (90)) were greater than for stages 10–15 (2055 (65)) (p<0.0002). However, TRIMPS/day were less for stages 1–9 (274 (10)) than for stages 10–15 (343 (11)) (p<0.01). Despite a trend to decline, no difference in supine resting HR was found between day 0 (53.2 (1.8) beats/min), day 10 (49.0 (2.8) beats/min), and day 17 (48.0 (2.6) beats/min) (p = 0.21). Whereas no significant group mean changes in HR or HRV indices were noted during the course of the race, significant inverse Pearson product-moment correlations were observed between all HRV indices relative to total TRIMPS and TRIMPS/day accumulated in race stages 10–15. Total TRIMPS correlated with square root of mean squared differences of successive RR intervals (r = –0.93; p<0.001), standard deviation of the RR intervals (r = –0.94; p<0.001), log normalised total power (r = –0.97; p<0.001), log normalised low frequency power (r = –0.79; p<0.02), and log normalised high frequency power (r = –0.94; p<0.001).

Conclusion: HRV may be strongly affected by chronic exposure to heavy exertion. Training volume and intensity are necessary to delineate the degree of these alterations.

     

Normes de sécurité et prévention des accidents du sport en France

Objectives. – To describe legal liabilities in France manage the safety of collective sport grounds, or normative rules for safety of personal devices to individual sport activities.Recent data. – Although patterns for game’s rules, emergency rescues, and insurance policies, are generally minded by organizers in sports meetings or individual activities, safety rules are sometimes less observed, and indeed neglected. Therefore that elicits increasing number of judicial examinations or even sentences condemnations versus sport’s responsible managers or municipal authorities, after action of victims for personal or collective injury in sport activity. Now several legal liabilities in France manage the safety of collective sport grounds, or normative rules (i.e. AFNOR, and more EN for European rules, also ISO 9000 everywhere, and ISO 14000 later) for safety of personal devices to individual sport activities. This statement explains the chief points and the possible evolution of these general enactive acts, as well in France as in European Community.     

Power output measurement during treadmill cycling

The study aim was to consider the use of a motorised treadmill as a cycling ergometry system by assessing predicted and recorded power output values during treadmill cycling. Fourteen male cyclists completed repeated cycling trials on a motorised treadmill whilst riding their own bicycle fitted with a mobile ergometer. The speed, gradient and loading via an external pulley system were recorded during 20-s constant speed trials and used to estimate power output with an assumption about the contribution of rolling resistance. These values were then compared with mobile ergometer measurements. To assess the reliability of measured power output values, four repeated trials were conducted on each cyclist. During level cycling, the recorded power output was 257.2 +/- 99.3 W compared to the predicted power output of 258.2 +/- 99.9 W (p > 0.05). For graded cycling, there was no significant difference between measured and predicted power output, 268.8 +/- 109.8 W vs. 270.1 +/- 111.7 W, p > 0.05, SEE 1.2 %. The coefficient of variation for mobile ergometer power output measurements during repeated trials ranged from 1.5 % (95 % CI 1.2 - 2.0 %) to 1.8 % (95 % CI 1.5 - 2.4 %). These results indicate that treadmill cycling can be used as an ergometry system to assess power output in cyclists with acceptable accuracy.     

Giro, Tour, and Vuelta in the same season

The exercise volume and intensity are reported of a male professional cyclist (age 30; VO2max 75.0 ml/kg/min) who successfully completed the 2001 Giro d'Italia (May), Tour de France (July), and Vuelta a Espa?a (September). The total exercise time during the Giro, Tour, and Vuelta was 90 hours 44 minutes (5444 minutes), 88 hours 23 minutes (5303 minutes), and 72 hours 59 minutes (4379 minutes) respectively. Heart rate telemetry during the races allowed the exercise intensity to be classified into three phases: I, below the first ventilatory threshold (VT1); II, between VT1 and the second ventilatory threshold (VT2); III, above VT2. Compared with the Giro and Tour, the lower exercise volume of the Vuelta (about 20% less total time) was compensated for by a considerably lower and higher contribution of phases I and III respectively. As a result, the total load (volume x intensity) in the three races was comparable.     

大白鼠游泳输出功测定仪的研制和疲劳方程Y＝A＋B／T的建立

研制了可以直接连续测量大鼠游泳输出功率的仪器，建立了一个理想的动物模型，通过分析对功率曲线进行函数拟合，得出了代表疲劳发生、作功能力下降的双曲线方程，通过分析衰竭时间和功、功率等参数的关系提出了衰竭阈概念。     

Comparison of the Power Knee and C-Leg during step-up and sit-to-stand tasks

For U.S. military service members with transfemoral amputations there are different prosthetic knee systems available that function differently. For example the C-Leg^® (C-Leg, Otto Bock Healthcare, GmbH, Duderstadt, Germany) is a passive microprocessor knee, and the Power Knee? (PK, Ossur, Reykjavík, Iceland) provides active positive power generation at the knee joint. This study examined both step-up and sit-to-stand tasks performed by service members using C-Leg and PK systems to determine if the addition of positive power generation to a prosthetic knee can improve symmetry and reduce impact to the remaining joints. For both tasks, average peak sagittal knee powers and vertical ground reaction forces (GRFs) were greater for the intact limb versus the amputated limb across PK and C-Leg groups. For the sit-to-stand task, peak knee power of the amputated limb was greater for PK users versus C-Leg users. Vertical GRFs of the intact limb were greater for the C-Leg versus the PK. The performance of the PK relative to the C-Leg during a STS task illustrated few differences between components and no effect on the intact limb.     

Reliability and validity of the Stryd Power Meter during different walking conditions

BackgroundThe Styrd Power Meter is gaining special interest for on-field gait analyses due to its low-cost and general availability. However, the reliability and validity of the Stryd during walking on positive slopes using different backpack loads have never been investigated.Research questionIs the Stryd Power Meter reliable and valid for quantifying gait mechanics during walking on positive inclines and during level walking incorporating load carriage?MethodsSeventeen participants from a police force rescue team performed 8 submaximal walking trials for 5-min at 3.6 km·h⁻¹ during different positive slope (1%, 10% and 20%) and backpack load (0%, 10%, 20%, 30% and 40% of body mass) conditions. Two Stryd devices were utilized for reliability analyses. Validity of cadence and ground contact time (GCT) were analyzed against a gold standard device (Optojump).ResultsThe Stryd demonstrated acceptable reliability [mean bias: < 2.5%; effect size (ES): < 0.25; standard error of the mean: < 1.7%; r: > 0.76] for power, cadence, and GCT. Validity measures (mean bias: <0.8%; ES: <0.07; r: >0.96; Lin’s Concordance Coefficient: 0.96; Mean Absolute Percent Error: <1%) for cadence were also found to be acceptable. The Stryd overestimated (P < 0.001; ES: >5.1) GCT in all the walking conditions. A significant systematic positive bias (P < 0.022; r = 0.56–0.76) was found in 7 conditions.Significance: The Stryd Power Meter appears to produce reliable measurements for power output, cadence and GCT. The Stryd produced valid measurements for cadence during walking on positive slopes and during level walking with a loaded backpack. However, the Stryd is not valid for measuring GCT during these walking conditions. This study adds novel data regarding the reliability and validity of this device and might be of particular interest for scientists, practitioners, and first responders seeking reliable devices to quantify gait mechanics during walking.     

Salivary IgA response of triathletes participating in the French Iron Tour

Athletes are susceptible to upper respiratory tract infections (URTI) during intense training and after major competitions. Secretory IgA, which is the predominant antibody of the mucosal immune system, is the major effector of host-resistance to many microorganisms causing URTI. Previous studies have shown that salivary IgA-mediated immunity decreases after a single short distance triathlon, but the effect of repeated triathlon competitions on secretory IgA levels remains unknown. The purpose of this study was to examine the salivary IgA response of elite triathletes in repeated triathlon races during the 2001 French Iron Tour (FIT). Eight triathletes participated in this study. Saliva samples were collected daily after waking up (fasting basal state), before (pre-race) and after (post-race) each day's competition. Salivary IgA, total protein, and flow rate were measured. Salivary IgA concentrations were measured by an enzyme-linked immunosorbent assay. The salivary flow rate was significantly decreased after each race compared with the fasting basal state (p < 0.01). The salivary IgA concentration of the fasting basal state decreased over the FIT and was even lower than that of the post-race values (p < 0.05). The salivary IgA secretion rate of the fasting basal state decreased by 51.9% over the FIT (p < 0.05). Our data suggest that intense exercise repeated daily has a cumulative negative effect on basal levels of salivary IgA.