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 purpose of this study was to investigate the influence of different cycling cadences on metabolic and kinematic parameters during subsequent running. Eight triathletes performed two incremental tests (running and cycling) to determine maximal oxygen uptake (VO2max) and ventilatory threshold (VT) values, a cycling test to assess the energetically optimal cadence (EOC), three cycle-run succession sessions (C-R, 30-min cycle + 15-min run), and one 45-min isolated run (IR). EOC, C-R, and IR sessions were realized at an intensity corresponding to VT + 5%. During the cycling bouts of C-R sessions, subjects had to maintain one of the three pedaling cadences corresponding to the EOC (72.5 +/- 4.6 rpm), the freely chosen cadence (FCC; 81.2 +/- 7.2 rpm), and the theoretical mechanical optimal cadence (MOC, 90 rpm; Neptune and Hull, 1999). Oxygen uptake (VO2) increased during the 30-min cycling only at MOC (+12.0%) and FCC (+10.4%). During the running periods of C-R sessions, VO2, minute ventilation, and stride-rate values were significantly higher than during the IR session (respectively, +11.7%, +15.7%, and +7.2%). Furthermore, a significant effect of cycling cadence was found on VO2 variability during the 15-min subsequent run only for MOC (+4.1%) and FCC (+3.6%). The highest cycling cadences (MOC, FCC) contribute to an increase in energy cost during cycling and the appearance of a VO2 slow component during subsequent running, whereas cycling at EOC leads to a stability in energy cost of locomotion with exercise duration. Several hypotheses are proposed to explain these results such as changes in fiber recruitment or hemodynamic modifications during prolonged exercise.Medicine & Science in Sports & Exercise 04/2002; 34(3):530-6. · 4.43 Impact Factor
Article: Effect of cadence, cycling experience, and aerobic power on delta efficiency during cycling.[show abstract] [hide abstract]
ABSTRACT: To examine the influence of cadence, cycling experience, and aerobic power on delta efficiency during cycling and to determine the significance of delta efficiency as a factor underlying the selection of preferred cadence. Delta efficiency (DE) was determined for 11 trained experienced cyclists (C), 10 trained runners (R), and 10 less-trained noncyclists (LT) at 50, 65, 80, 95, and 110 rpm. Preferred cadence (PC) was determined at 100, 150, and 200 W for C and R and at 75, 100, and 150 W for LT. Gas exchange at each power output (PO) was measured on a separate day, and the five cadences were randomly ordered on each occasion. It was hypothesized that: a) cyclists are most efficient at the higher cadences at which they are accustomed to training and racing, i.e., there will be a trend for DE to increase with increases in cadence; b) cyclists and runners will exhibit similar DE across the range of cadences tested; and c) DE of less-trained subjects will be lower than that of cyclists and runners. PCs of C and R were similar and did not change appreciably with PO (100 W:C, 95.6 +/- 10.8; R, 92.0 +/- 8.5: 150 W:C, 94.4 +/- 10.3; R, 92.9 +/- 7.8: 200 W:C, 92.2 +/- 7.2; R, 91.8 +/- 7.9 rpm). The PC of LT was significantly lower and decreased with increases in power output (75 W: 80.0 +/- 15.3; 100 W; 77.5 +/- 15.1; 150 W; 69.1 +/- 11.9 rpm). The first hypothesis was rejected because analysis of the cyclists' data alone revealed no systematic increase in DE as cadence was increased [F(4,40) = 0.272, P = 0.894]. Repeated measures ANOVA on all three groups revealed no group x cadence interaction [F(8,112) = 0.589, P = 0.785]. Again there was no systematic effect of cadence on DE [F(4,112) = 1.058, P = 0.381]. The second and third hypotheses were also rejected since there was no group main effect, i.e., DE of cyclists, runners, and less-trained subjects were not significantly different [F(2,28) = 1.397, P = 0.264]. Pedaling cadence did not have a dramatic effect on DE in any group. Muscular efficiency, as measured indirectly by delta efficiency, appears to remain relatively constant at approximately 24%, regardless of cycling experience or fitness level.Medicine & Science in Sports & Exercise 10/2000; 32(9):1630-4. · 4.43 Impact Factor
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ABSTRACT: Based on the resistance-rpm relationship for cycling, which is not unlike the force-velocity relationship of muscle, it is hypothesized that the cadence which requires the minimal muscle activation will be progressively higher as power output increases. To test this hypothesis, subjects were instrumented with surface electrodes placed over seven muscles that were considered to be important during cycling. Measurements were made while subjects cycled at 100, 200, 300, and 400 W at each cadence: 50, 60, 80, 100, and 120 rpm. These power outputs represented effort which was up to 32% of peak power output for these subjects. When all seven muscles were averaged together, there was a proportional increase in EMG amplitude each cadence as power increased. A second-order polynomial equation fit the EMG:cadence results very well (r2 = 0.87- 0.996) for each power output. Optimal cadence (cadence with lowest amplitude of EMG for a given power output) increased with increases in power output: 57 +/- 3.1, 70 +/- 3.7, 86 +/- 7.6, and 99 +/- 4.0 rpm for 100, 200, 300, and 400 W, respectively. The results confirm that the level of muscle activation varies with cadence at a given power output. The minimum EMG amplitude occurs at a progressively higher cadence as power output increases. These results have implications for the sense of effort and preferential use of higher cadences as power output is increased.Medicine & Science in Sports & Exercise 08/2000; 32(7):1281-7. · 4.43 Impact Factor