Neuromuscular, metabolic, and kinetic adaptations for skilled pedaling performance in cyclists.
ABSTRACT The purpose of this study was to clarify the reason for the difference in the preferred cadence between cyclists and noncyclists.
Male cyclists and noncyclists were evaluated in terms of pedal force, neuromuscular activity for lower extremities, and oxygen consumption among the cadence manipulation (45, 60, 75, 90, and 105 rpm) during pedaling at 150 and 200 W. Noncyclists having the same levels of aerobic and anaerobic capacity as cyclists were chosen from athletes of different sports to avoid any confounding effect from similar kinetic properties of cyclists for lower extremities (i.e., high speed contraction and high repetitions in prolonged exercise) on both pedaling performance and preferred cadence.
The peak pedal force significantly decreased with increasing of cadence in both groups, and the value for noncyclists was significantly higher than that for cyclists at each cadence despite the same power output. The normalized iEMG for vastus lateralis and vastus medialis muscles increased in noncyclists with rising cadence; however, cyclists did not show such a significant increase of the normalized iEMG for the muscles. On the other hand, the normalized iEMG for biceps femoris muscle showed a significant increase in cyclists while there was no increase for noncyclists. Oxygen consumption for cyclists was significantly lower than that for noncyclists at 105 rpm for 150 W work and at 75, 90, and 105 rpm for 200 W work.
We conclude that cyclists have a certain pedaling skill regarding the positive utilization for knee flexors up to the higher cadences, which would contribute to a decrease in peak pedal force and which would alleviate muscle activity for the knee extensors. We speculated that pedaling skills that decrease muscle stress influence the preferred cadence selection, contributing to recruitment of ST muscle fibers with fatigue resistance and high mechanical efficiency despite increased oxygen consumption caused by increased repetitions of leg movements.
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ABSTRACT: The aim of this study was to analyze the pedaling rate (PR) adopted by professional cyclists in different mountain passes. PR, heart rate (HR), velocity and power to overcome gravity were monitored during special (HM), 1st (M1), 2nd (M2) and 3rd (M3) category mountain passes. HM and M1 within high-mountain stages were classified into mountain passes before the final mountain pass of the stage (M-BF) and mountain passes placed in the final of the stage (M-F). PR was significantly higher (P < 0.05) in M3 (82 +/- 1 rpm) than that in M2 (75 +/- 3 rpm), M1 (75 +/- 2 rpm) and HM (73 +/- 1 rpm). Velocity and power output decreased in the following order: M3, M2, M1 and HM. Also, greater values (P < 0.05) were observed in M-BF (24.1 +/- 0.8 km h(-1) and 308.5 +/- 10.4 W) and in M-F (17.6 +/- 0.9 km h(-1) and 270.1 +/- 9.9 W). In addition, PR was higher (P < 0.05) in M-BF (79 +/- 2 rpm) than that in M-F (73 +/- 1 rpm). In conclusion, PR was modified according to the characteristics and the race strategies adopted by the cyclists, thus the cyclists chose higher PR to improve their performance.Arbeitsphysiologie 07/2008; 103(5):515-22. DOI:10.1007/s00421-008-0745-3 · 2.30 Impact Factor
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ABSTRACT: Freely chosen pedalling rate during cycling represents a voluntary rhythmic movement. It is unclear to what extent this is influenced by internal (e.g. loading on the cardiopulmonary system) and external (e.g. mechanical loading) conditions. It is also unclear just how robust a voluntary motor rhythm, the freely chosen pedalling rate, actually is. The present study investigated (N = 8) whether or not the freely chosen pedalling rate during submaximal cycling was affected by separate increases in loading on the cardiopulmonary system (changed by exposure to acute simulated altitude of 3,000 m above sea level) and mechanical loading (changed by exposure to increased power output and thereby pedal force). We also investigated (N = 7) whether or not the freely chosen pedalling rate and another voluntary motor rhythm, unimanual unloaded index finger tapping rate, shared common characteristics of steadiness and individuality over a 12-week period. Results showed that the freely chosen pedalling rate was unaffected by increased loading on the cardiopulmonary system at constant mechanical loading, and vice versa. Further, the pedalling rate was steady in the longitudinal perspective (as was the tapping rate), and like tapping rate, pedalling rate was highly individual. In total this indicated that freely chosen pedalling rate primarily is a robust innate voluntary motor rhythm, likely under primary influence of central pattern generators that again are minimally affected by internal and external conditions during submaximal cycling.Experimental Brain Research 05/2008; 186(3):365-73. DOI:10.1007/s00221-007-1240-5 · 2.17 Impact Factor
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ABSTRACT: An isometric maximal voluntary contraction (iMVC) is mostly used for the purpose of EMG normalization, a procedure described in the scientific literature in order to compare muscle activity among different muscles and subjects. However, the use of iMVC has certain limitations. The aims of the present study were therefore to propose a new method for the purpose of EMG amplitude normalization in cycling and assess its reliability. Twenty-three cyclists performed 10 trials of a maximal isokinetic protocol (MIP) on a cycle ergometer, then another four sub-maximal trials, whilst the EMG activity of four lower limbs muscles was registered. During the 10 trials power output (CV=2.19) and EMG activity (CV between 4.46 and 8.70) were quite steady. Furthermore, their maximal values were reached within the 4th trial. In sub-maximal protocol EMG activity exhibited an increase as a function of exercise intensity. MIP entails a maximal dynamic contraction of the muscles involved in the pedalling action and the normalization session is performed under the same biomechanical conditions as the following test session. Thus, it is highly cycling-specific. MIP has good logical validity and within-subject reproducibility. Three trials are enough for the purpose of EMG normalization in cycling.Journal of electromyography and kinesiology: official journal of the International Society of Electrophysiological Kinesiology 02/2008; 19(3):e162-70. DOI:10.1016/j.jelekin.2007.11.013 · 1.73 Impact Factor