Metabolic and Neuromuscular Adaptations to Endurance Training in Professional Cyclists. A Longitudinal Study.

Abstract

Professional road cycling is an extreme endurance sport. Approximately 30,000-35,000 km are cycled each year and the racing season of professional riders includes ϳ90 competition days. In addition, despite the long duration of cycling events such as 3-week stage races, the relative contribution of intense exercise is surprisingly high during the more physically taxing events (mountain passes, time trials, sprints, "breakaways" etc.) [1].Several investigators have analyzed a number of physiological variables in professional cyclists, both in laboratory [2][3][4][5][6][7] and field settings [1,[8][9][10]. However, no prospective, long-term investigation has established the specific physiological adaptations which occur in professional cyclists as a response to training and competition during a typical sports season (generally including different periods in terms of training volume and/or intensity; i.e., precompetition or training, competition, and postcompetition or "active" rest periods). In a recent study (unpublished data), we found no overall training-effect on the ventilatory response (i.e., pulmonary ventilation, tidal volume, ventilatory equivalents, "timing" of respiration, etc.) in the same 13 subjects who formed the present study population. It was therefore considered of interest to extend this investigation to determine whether meta- ]. Finally, rms-EMG tended to increase during the season, with significant differences (pϽ0.05) observed mainly between the competition and rest periods at most workloads. In contrast, precompetition MPF values increased (pϽ0.05) with respect to resting values at most submaximal workloads but fell (pϽ0.05) during the competition period. Our findings suggest that endurance conditioning induces the following general adaptations in elite athletes: (1) lower circulating lactate and increased reliance on aerobic metabolism at a given submaximal intensity, and possibly (2) an enhanced recruitment of motor units in active muscles, as suggested by rms-EMG data.

Do neuromuscular adaptations occur in endurance-trained boys and men?

“…To the best of our knowledge, this is the first study to examine Q 30 in endurance-trained boys and men. Our results concur with previous studies in adults (Lattier et al 2003;Lucía et al 2000) that suggested that endurance training increases muscle activation and enhances motor-unit recruitment. However, we feel that because our findings could not correlate performance with Q 30 differences, the relationship between Q 30 and muscle performance is unclear, at least as far as endurance training is concerned.…”

“…Comparable data on the possible effects of endurance training on muscle performance and neuromuscular adaptations are limited. Although some studies suggest increased muscle activation and possibly increased strength in adult endurance athletes compared with untrained adults (Lattier et al 2003;Lucía et al 2000), there are no comparable data in children.…”

Training-Intensity Distribution in Road Cyclists: Objective Versus Subjective Measures

“…11,12 This seems to be reflected in the type of training engaged in by both elite and recreational endurance athletes whom seem to train at an intensity distribution that consists of ~80% of the training sessions performed at zone 1 and the remaining ~20% at zone 2 and 3. 7,8,13 Lucia et al 14 quantified time spent in three heart rate (HR) zones during different training phases in professional cyclists showing a shift towards a higher proportion of moderate to high-intensity training when getting closer to the competitions. Along with monitoring HR, the availability of mobile power meters for cyclists has resulted in the widespread monitoring of power output (PO) in competitive cycling.…”

Effects of High-Intensity Training on Physiological and Hormonal Adaptions in Well-Trained Cyclists

“…In endurance sports, these include the duration and intensity of individual training sessions, the frequency of training sessions, and the organizational pattern of these stimulus variables over time. Recent descriptive studies of some of the world_s best endurance athletes have shown that successful athletes in cycling (14,25,35), running (1,2), and cross-country skiing (21,22,33) perform a high volume of low-intensity training (LIT) (defined as work eliciting a stable blood lactate concentration [la j ] of less than approximately 2 mmolIL j1 ) in addition to much smaller but substantial proportions of both moderate-intensity training (MIT) (2-4 mmolIL j1 blood lactate) and high-intensity training (HIT) (training above maximum lactate steady-state intensity [94 mmolIL j1 blood lactate]) throughout the preparation period. The majority of descriptive studies present a ''pyramidal'' training intensity distribution (TID), with high volume of LIT, substantial MIT, and less HIT, whereas a few studies suggest athletes to adopt a ''polarized'' TID (reduced volume of MIT, somewhat higher HIT), which have been proposed to give superior endurance adaptations (27,29).…”