Optimal pedaling rate estimated from neuromuscular fatigue for cyclists.

This study was designed to examine the optimal pedaling rate for pedaling exercise at a given work intensity for cyclists. Six college-aged cyclists each performed six sessions of heavy pedaling exercise at individually selected work rates based on their aerobic capacity. The optimal pedaling rate was evaluated on the basis of minimal neuromuscular fatigue as evidenced by the integrated electromyogram (iEMG) slope defined by the changes in iEMG as a function of time. The means of the iEMG slope demonstrated a quadratic curve versus pedaling rate. The mean values at 80 rpm (0.53 (SD 0.20) microV.min-1) and 90 rpm (0.67 (SD 0.23) microV.min-1) were significantly smaller than those values at any other pedaling rate. On the other hand, the mean value of oxygen uptake (VO2) expressed as a percent of the subject's maximal VO2 (% VO2max) at each pedaling rate also showed a quadratic curve with minimal values at about 60 or 70 rpm. VO2 at 70 rpm (84.0 (SD 5.0) % VO2max) was significantly smaller than those values at 80 rpm (86.3 (SD 3.5) % VO2max), 90 rpm (87.4 (SD 3.8) % VO2max), and 100 rpm (90.1 (SD 3.8) % VO2max). These data strongly suggest that the optimal pedaling rate estimated from neuromuscular fatigue in working muscles is not coincident with the pedaling rate at which the smallest VO2 was obtained, but with the preferred pedaling rate of the subjects. Our findings also suggest that the reason that cyclists prefer a higher pedaling rate is closely related to the development of neuromuscular fatigue in the working muscles.

[1]  D. Poole.  Role of exercising muscle in slow component of VO2. , 1994, Medicine and science in sports and exercise.

[2]  P. Raven,et al.  Effect of pedal rate on cardiorespiratory responses during continuous exercise. , 1992, Medicine and science in sports and exercise.

[3]  E. Coyle,et al.  Cycling efficiency is related to the percentage of type I muscle fibers. , 1992, Medicine and science in sports and exercise.

[4]  S A Kautz,et al.  Physiological and biomechanical factors associated with elite endurance cycling performance. , 1991, Medicine and science in sports and exercise.

[5]  R. Patterson,et al.  Bicycle pedalling forces as a function of pedalling rate and power output. , 1990, Medicine and science in sports and exercise.

[6]  J. Coast,et al.  Optimal pedalling rate in prolonged bouts of cycle ergometry. , 1986, Medicine and science in sports and exercise.

[7]  N. Vøllestad,et al.  Effect of varying exercise intensity on glycogen depletion in human muscle fibres. , 1985, Acta physiologica Scandinavica.

[8]  Hannover,et al.  Relationship Between Work Load, Pedal Frequency, and Physical Fitness* , 1984, International journal of sports medicine.

[9]  H. Devries,et al.  The relation between critical power and neuromuscular fatigue as estimated from electromyographic data. , 1982, Ergonomics.

[10]  A. R. Lind,et al.  Evaluation of amplitude and frequency components of the surface EMG as an index of muscle fatigue. , 1982, Ergonomics.

[11]  T Moritani,et al.  Electromyographic manifestations of muscular fatigue. , 1982, Medicine and science in sports and exercise.

[12]  R. Armstrong,et al.  Patterns of glycogen loss in muscle fibers: response to arterial occlusion during exercise. , 1981, Journal of applied physiology: respiratory, environmental and exercise physiology.

[13]  J. Hagberg,et al.  Effect of pedaling rate on submaximal exercise responses of competitive cyclists. , 1981, Journal of applied physiology: respiratory, environmental and exercise physiology.

[14]  M Hagberg,et al.  Muscular endurance and surface electromyogram in isometric and dynamic exercise. , 1981, Journal of applied physiology: respiratory, environmental and exercise physiology.

[15]  R T Withers,et al.  Muscle respiratory capacity and fiber type as determinants of the lactate threshold. , 1980, Journal of applied physiology: respiratory, environmental and exercise physiology.

[16]  H Löllgen,et al.  Muscle metabolites, force, and perceived exertion bicycling at varying pedal rates. , 1980, Medicine and science in sports and exercise.

[17]  Melvin R. Ramey,et al.  Influence of Pedalling Rate and Power Output on Energy Expenditure During Bicycle Ergometry , 1977 .

[18]  R. Fitts,et al.  Lactate and contractile force in frog muscle during development of fatigue and recovery. , 1976, The American journal of physiology.

[19]  G. Brooks,et al.  Muscular efficiency during steady-rate exercise: effects of speed and work rate. , 1975, Journal of applied physiology.

[20]  R. Stein,et al.  The relation between the surface electromyogram and muscular force. , 1975, The Journal of physiology.

[21]  P D Gollnick,et al.  Selective glycogen depletion pattern in human muscle fibres after exercise of varying intensity and at varying pedalling rates , 1974, The Journal of physiology.

[22]  B J Whipp,et al.  Oxygen uptake kinetics for various intensities of constant-load work. , 1972, Journal of applied physiology.

[23]  B. Ekblom,et al.  The influence of physical training and other factors on the subjective rating of perceived exertion. , 1971, Acta physiologica Scandinavica.