NEUROMECHANICS OF CYCLING: OPPORTUNITIES FOR OPTIMIZING PERFORMANCE

From the very simple (external power output) to the more complex variables (effective force profile, index of effectiveness, specific joint power) up to a neuro-musculo-skeletal integrative approach, we will focus on the following items: a clear definition of each concepts and variables, the tools needed for its accurate measurement and the state of scientific knowledge (and/or illustration) about its potential interest for the cycling performance. The ultimate approach using musculoskeletal models will also be mentioned just to give an idea of the potential interest to use them in a cycling performance enhancement endeavor

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\u27s 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 \u3c .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

A simple method for measuring power, force, velocity properties, and mechanical effectiveness in sprint running

International audienceThis study aimed to validate a simple field method for determining force– and power–velocity relationships and mechanical effectiveness of force application during sprint running. The proposed method, based on an inverse dynamic approach applied to the body center of mass, estimates the step-averaged ground reaction forces in runner's sagittal plane of motion during overground sprint acceleration from only anthropometric and spatio-temporal data. Force– and power–velocity relationships, the associated variables, and mechanical effectiveness were determined (a) on nine sprinters using both the proposed method and force plate measurements and (b) on six other sprinters using the proposed method during several consecutive trials to assess the inter-trial reliability. The low bias (<5%) and narrow limits of agreement between both methods for maximal horizontal force (638 ± 84 N), velocity (10.5 ± 0.74 m/s), and power output (1680 ± 280 W); for the slope of the force–velocity relationships ; and for the mechanical effectiveness of force application showed high concurrent validity of the proposed method. The low standard errors of measurements between trials (<5%) highlighted the high reliability of the method. These findings support the validity of the proposed simple method, convenient for field use, to determine power, force, velocity properties, and mechanical effectiveness in sprint running

Electromyographic analysis of pedaling: A review

Although pedaling is constrained by the circular trajectory of the pedals, it is not a simple movement. This review attempts to provide an overview of the pedaling technique using an electromyographic (EMG) approach. Literature concerning the electromyographic analysis of pedaling is reviewed in an effort to make a synthesis of the available information, and to point out its relevance for researchers, clinicians and/or cycling/triathlon trainers. The first part of the review depicts methodological aspects of the EMG signal recording and processing. We show how the pattern of muscle activation during pedaling can be analyzed in terms of muscle activity level and muscle activation timing. Muscle activity level is generally quantified with root mean square or integrated EMG values. Muscle activation timing is studied by defining EMG signal onset and offset times that identify the duration of EMG bursts and, more recently, by the determination of a lag time maximizing the cross-correlation coefficient. In the second part of the review, we describe whether the patterns of the lower limb muscles activity are influenced by numerous factors affecting pedaling such as power output, pedaling rate, body position, shoe-pedal interface, training status and fatigue. Some research perspectives linked to pedaling performance are discussed throughout the manuscript and in the conclusion

Mesure de l’activité musculaire par électromyographie

International audienc

Chapitre 14. Les techniques de refroidissement du corps : stratégies de cooling pré- et post-exercice

Introduction Si de nombreux produits rafraîchissants sont aujourd'hui proposés aux athlètes (vestes rafraîchissantes, douches froides, chambres froides, piscine d'acclimatation, ventilateur de brume glacée, tentes portables climatisées...), plusieurs questions pratiques doivent être posées. Celles-ci sont entre autres relatives aux difficultés de transport et de stockage, au coût et à l'utilisation (plus ou moins facile) de ces différents procédés. Les entraîneurs et les athlètes sont donc pa..

Analysis of elite road‐cycling sprints in relation to power‐velocity‐endurance profile: A longitudinal one‐case study

International audienceThe aims of the present study were to characterize the mechanical output of final road sprints of an elite sprinter during international competitions in relation to his power-velocity-endurance characteristics and to investigate the relationship between this sprint performance and the power produced during preceding phases of the race. The sprinter performed a set of short and long sprints (5 to 15-s) on a cycle ergometer to determine his maximal power-velocity-endurance profile. Based on eleven races, the distribution of power throughout each race, peak and mean power (Ppeak and Pmean) and associated pedaling rates (vPpeak and vPmean) during the final sprint were analyzed. The power-velocity-endurance profile of the sprinter indicated that his theoeretical mean maximal power and corresponding optimal pedaling rate ranged from 20.0 W.kg−1 (124 rpm) for a 1-s sprint to 15.0 W.kg−1 (109 rpm) for 20 s. Race data showed that final road sprints were mainly performed on the ascending limb of the power-velocity relationship (vPpeak, 104 ± 8 and vPmean, 101 ± 8 rpm). Additionally, Ppeak and Pmean were lower than the theoretical maximal power determined from the power-velocity-endurance profile (9.9 ± 7.0% and 10.6 ± 9.8%, respectively), which highlighted a significant state of fatigue induced by the race. Finally, sprint power exhibited a high variability between races and was strongly related to the level of power produced during the last minute before the sprint. These findings show the importance of considering both the power-velocity-endurance qualities and the power demand of the last lead-up phase before the sprint in order to optimize final sprint performance