Effect of cycling cadence on subsequent 3 km running performance in well trained triathletes

OBJECTIVES: To investigate the effect of three cycling cadences on a subsequent 3000 m track running performance in well trained triathletes. METHODS: Nine triathletes completed a maximal cycling test, three cycle-run succession sessions (20 minutes of cycling + a 3000 m run) in random order, and one isolated run (3000 m). During the cycling bout of the cycle-run sessions, subjects had to maintain for 20 minutes one of the three cycling cadences corresponding to 60, 80, and 100 rpm. The metabolic intensity during these cycling bouts corresponded approximately to the cycling competition intensity of our subjects during a sprint triathlon (> 80% VO(2)max). RESULTS: A significant effect of the prior cycling exercise was found on middle distance running performance without any cadence effect (625.7 (40.1), 630.0 (44.8), 637.7 (57.9), and 583.0 (28.3) seconds for the 60 rpm run, 80 rpm run, 100 rpm run, and isolated run respectively). However, during the first 500 m of the run, stride rate and running velocity were significantly higher after cycling at 80 or 100 rpm than at 60 rpm (p<0.05). Furthermore, the choice of 60 rpm was associated with a higher fraction of VO(2)max sustained during running compared with the other conditions (p<0.05). CONCLUSIONS: The results confirm the alteration in running performance completed after the cycling event compared with the isolated run. However, no significant effect of the cadence was observed within the range usually used by triathletes.     

Relationship between strength level and pedal rate

The purpose of this study was to examine the relationship between strength capacity and preferred and optimal cadence in well trained cyclists. Eighteen cyclists participated in this study. Each subject completed three sessions. The initial session was to evaluate the maximal isokinetic voluntary contraction level of lower limb. The second session was an incremental test to exhaustion. During the third session subjects performed a constant cycling exercise (20 min) conducted at five randomly cadences (50, 70, 90, 110 rpm) and at the preferred cadence (FCC) at the power reached at ventilatory threshold. Cardiorespiratory and EMG values were recorded. A metabolic optimum (EOC) was observed at 63.5 +/- 7.8 rpm different from preferred cadence (FCC, 90.6 +/- 9.1 rpm). No difference was found between FCC and the neuromuscular optimal cadence (NOC, 93.5 +/- 4). Significant relationships were found between EOC, NOC and strength capacities (r = - 0.75 and - 0. 63), whereas FCC was only related with VO2max (r = 0.59). The main finding of this study was that during submaximal cycling energetically optimal cadence or neuromuscular optimum in trained cyclists was significantly related with strength capacity and whereas preferred cadence seems to be related with endurance training status of cyclists.     

Cadence selection affects metabolic responses during cycling and subsequent running time to fatigue

Objectives: To investigate the effect of cadence selection during the final minutes of cycling on metabolic responses, stride pattern, and subsequent running time to fatigue.

Methods: Eight triathletes performed, in a laboratory setting, two incremental tests (running and cycling) to determine peak oxygen uptake (VO₂PEAK) and the lactate threshold (LT), and three cycle-run combinations. During the cycle-run sessions, subjects completed a 30 minute cycling bout (90% of LT) at (a) the freely chosen cadence (FCC, 94 (5) rpm), (b) the FCC during the first 20 minutes and FCC–20% during the last 10 minutes (FCC–20%, 74 (3) rpm), or (c) the FCC during the first 20 minutes and FCC+20% during the last 10 minutes (FCC+20%, 109 (5) rpm). After each cycling bout, running time to fatigue (T_max) was determined at 85% of maximal velocity.

Results: A significant increase in T_max was found after FCC–20% (894 (199) seconds) compared with FCC and FCC+20% (651 (212) and 624 (214) seconds respectively). VO₂, ventilation, heart rate, and blood lactate concentrations were significantly reduced after 30 minutes of cycling at FCC–20% compared with FCC+20%. A significant increase in VO₂ was reported between the 3rd and 10th minute of all T_max sessions, without any significant differences between sessions. Stride pattern and metabolic variables were not significantly different between T_max sessions.

Conclusions: The increase in T_max after FCC–20% may be associated with the lower metabolic load during the final minutes of cycling compared with the other sessions. However, the lack of significant differences in metabolic responses and stride pattern between the run sessions suggests that other mechanisms, such as changes in muscular activity, probably contribute to the effects of cadence variation on T_max.

     

The acute effects of prior cycling cadence on running performance and kinematics

PURPOSE: To determine if cycling cadence affects subsequent running speed through changes in stride frequency. METHODS: Thirteen male triathletes completed three sessions of testing on separate days. During the first session (control condition), the participants completed a 30-min cycling bout of high intensity at their preferred cadence, immediately followed by a 3200-m run at race effort. During the second and third sessions (fast condition and slow condition), the participants repeated the protocol but with a cycling cadence 20% faster or 20% slower than the control condition. RESULTS: After cycling at a fast cadence, the 3200-m run time averaged nearly a min faster than after cycling at a slow cadence. Running stride frequency after cycling at a fast cadence was significantly greater than after cycling at a normal or slow cadence. Stride length did not differ between conditions. Joint kinematics at foot strike, mid-stance, toe-off, and mid-swing were not different between conditions. CONCLUSION: Increased cycling cadence immediately before running increased stride frequency and, as a result, increased speed.     

Performance level and cardiopulmonary responses during a cycle-run trial

To determine the effect of triathlete performance level on the cardiorespiratory responses elicited by the cycle-run succession, eight regionally and nationally-ranked (Competitive) and five internationally-ranked (Elite) male triathletes underwent four successive laboratory trials: 1) an incremental treadmill test, 2) an incremental cycle test, 3) 30 min of cycling followed by 20 min of running (C-R), and 4) a 20-min control run (R) at the same speed as the run in C-R. Before and 10 min after the third and fourth trials the triathletes underwent lung function testing: spirometry and diffusing capacity testing for carbon monoxide (DL(CO)). During the C-R trial blood samples were drawn to measure venous lactate concentration. During all trials ventilatory data were collected every minute using an automated breath-by-breath system. The results showed that 1) the oxygen uptake (VO2) of post-cycling running versus running alone was similar for both groups; 2) the ventilatory responses (VE, VE/VO2, VE/VC02 and f) of C-R running versus R were significantly higher (P < 0.005) for the Competitive group; and 3) a significant decrease (P< 0.05) in DL(CO) was also noted after the C-R trial in the Competitive group but not in the Elite group. We concluded that 1) the ventilatory responses during a run subsequent to cycling may be related to the triathlete performance level, and 2) the C-R trial induced specific alterations in pulmonary function that may be associated with respiratory muscle alteration and exercise-induced hypoxemia in the Competitive triathletes.     

Effect of cadence on the economy of uphill cycling.

Competitive cyclists generally climb hills at a low cadence despite the recognized advantage in level cycling of high cadences. To test whether a high cadence is more economical than a low cadence during uphill cycling, nine experienced cyclists performed steady-state bicycling exercise on a treadmill under three randomized trials. Subjects bicycled at 11.3 km.h-1 up a 10% grade while 1) pedalling at 84 rpm in a sitting position-84 Sit, 2) pedalling at 41 rpm in a standing position-41 Stand, and 3) pedalling at 41 rpm in a sitting position-41 Sit. Heart rate (HR), oxygen consumption (VO2), ventilation (VE), and respiratory exchange ratio were measured continuously during 5-min trials and averaged over the last 2 min. Additionally, rating of perceived exertion was recorded during the fifth minute of each trial, and blood lactate concentration was recorded immediately before and after each trial. Significantly lower values for HR, VO2 and VE were recorded during 84 Sit (164 +/- 3 bpm, 51.8 +/- 0.8 ml.min-1 x kg-1, 94 +/- 5 l.min-1) than for either the 41 Stand (171 +/- 2 bpm, 53.1 +/- 0.7 ml.min-1 x kg-1, 105 +/- 6 l.min-1) o 41 Sit (168 +/- 2 bpm, 53.1 +/- 0.8 ml.min-1 x kg-1, 101 +/- 6 l.min-1) trials. No other differences were noted between trials for any of the measured variables. We conclude that uphill cycling is more economical at a high versus a low cadence.     

Cadence and workload effects on pedaling technique of well-trained cyclists

This study investigated the effects of changing cadence and workload on pedaling technique. Eight cyclists were evaluated during an incremental maximal cycling and two 30-minute submaximal trials at 60 % and 80 % of maximal power output (W (60 %) and W (80 %), respectively). During submaximal 30-minute trials, they cycled for 10 minutes at a freely chosen cadence (FCC), 10 minutes at a cadence 20 % above FCC (FCC + 20 %), and 10 minutes at a cadence 20 % below FCC (FCC - 20 %). Pedal forces and kinematics were evaluated. The resultant force (RF), effective force (EF), index of effectiveness (IE) and IE during propulsive and recovery phase (IEprop and IErec, respectively) were computed. For W (60 %), FCC - 20 % and FCC presented higher EFmean (69 +/- 9 N and 66 +/- 14 N, respectively) than FCC + 20 % (52 +/- 14 N). FCC presented the highest IEprop (81 +/- 4 %) among the cadences (74 +/- 4 and 78 +/- 5 % for FCC - 20 % and FCC + 20 %, respectively). For W (80 %), FCC presented higher EFmean (81 +/- 5 N) than FCC + 20 % (72 +/- 10 N). The FCC - 20 % presented the lower IEprop (71 +/- 7 %) among the cadences. The EFmin was higher for W (80 %) than W (60 %) for all cadences. The IE was higher at W (80 %) (61 +/- 5 %) than W (60 %) (54 +/- 9 %) for FCC + 20 % (all p < 0.05). Lower cadences were more effective during the recovery phase for both intensities and FCC was the best technique during the propulsive phase.     

Cardiovascular effects of cadence and workload

Increases in cadence may augment SV during submaximal cycling (> 65 % VO2max) via effects of increased muscle pump activity on preload. At lower workloads (45 - 65 % VO2max), SV tends to plateau, suggesting that effects of increases in cadence on pump activity have little influence on SV. We hypothesized that cadence-induced increases in CO at submaximal workloads, where SV tends to plateau, are due to elevations in HR and/or O2 extraction. SV, CO, HR, VO2, and delta a - vO2 were assessed at 80 and 100 rpm during workloads of 50 % (LO) or 65 % (HI) of VO2max in 11 male cyclists. No changes in SV were seen. CO was higher at 100 rpm in 10 of 11 subjects at LO (18.1 +/- 2.7 vs. 17.2 +/- 2.6 L/min). VO2 at both workloads was greater at 100 than 80 rpm as was HR (LO: 129 +/- 11 vs. 121 +/- 10 beats/min; HI: 146 +/- 13 vs. 139 +/- 14 beats/min) (p < 0.05). delta a - vO2 was greater at HI compared to LO at 80 (15.1 +/- 1.6 vs. 13.6 +/- 1.3 ml) and 100 rpm (16.0 +/- 1.7 vs. 15.1 +/- 1.6 ml) (p < 0.05). Results suggest that increases in O2 demand during low submaximal cycling (50 % VO2max) at high cadences are met by HR-induced increases in CO. At higher workloads (65 % VO2max), inability of higher cadences to increase CO and O2 delivery is offset by greater O2 extraction.     

The role of cadence on the VO2 slow component in cycling and running in triathletes.

The purpose of this study was to compare the effect of two different types of cyclic severe exercise (running and cycling) on the VO2 slow component. Moreover we examined the influence of cadence of exercise (freely chosen [FF] vs. low frequency [LF]) on the hypothesis that: 1) a stride frequency lower than optimal and 2) a pedalling frequency lower than FF one could induce a larger and/or lower VO2 slow component. Eight triathletes ran and cycled to exhaustion at a work-rate corresponding to the lactate threshold + 50% of the difference between the work-rate associated with VO2max and the lactate threshold (delta 50) at a freely chosen (FF) and low frequency (LF: - 10 % of FF). The time to exhaustion was not significantly different for both types of exercises and both cadences (13 min 39 s, 15 min 43 s, 13 min 32 s, 15 min 05 s for running at FF and LF and cycling at FF and LF, respectively). The amplitude of the VO2 slow component (i.e. difference between VO2 at the last and the 3rd min of the exercise) was significantly smaller during running compared with cycling, but there was no effect of cadence. Consequently, there was no relationship between the magnitude of the VO2 slow component and the time to fatigue for a severe exercise (r = 0.20, p = 0.27). However, time to fatigue was inversely correlated with the blood lactate concentration for both modes of exercise and both cadences (r = - 0.42, p = 0.01). In summary, these data demonstrate that: 1) in subjects well trained for both cycling and running, the amplitude of the VO2 slow component at fatigue was larger in cycling and that it was not significantly influenced by cadence; 2) the VO2 slow component was not correlated with the time to fatigue. If the nature of the linkage between the VO2 slow component and the fatigue process remains unclear, the type of contraction regimen depending on exercise biomechanic characteristics seems to be determinant in the VO2 slow component phenomenon for a same level of training.     

A physiological comparison of synchronous and asynchronous hand cycling

The purpose of this study was to compare submaximal physiological responses (oxygen uptake, ventilation, heart rate) and gross mechanical efficiency between synchronous and asynchronous hand cycling at different cadences. Thirteen non-disabled men (22.4 +/- 1.6 yr) performed two submaximal exercise tests on a treadmill, using synchronous and asynchronous crank settings in counter balanced order. Tests were performed using a commercially available hand cycle unit that was attached to a hand rim wheelchair. Each test consisted of five 5-min exercise bouts at 36, 47, 55, 65, and 84 rpm. ANOVA for repeated measures showed a significant effect of crank mode (p < 0.001) and cadence (p < 0.001), as well as an interaction effect between both (p < 0.01). Physiological responses were lower, and efficiency higher, in synchronous versus asynchronous hand cycling at all cadences. Post-hoc analysis of the (overall) effect of cadence showed significantly higher physiological responses and lower efficiency at the higher (84 vs. 65 rpm and 65 vs. 55 rpm) and lower (36 vs. 47 rpm) cadences. The interaction effect indicates that the effect of crank mode was dependent on cadence, showing a larger difference between synchronous and asynchronous hand cycling at 84 vs. 65 rpm and at 36 vs. 47 rpm. It is concluded that, in contrast to previous results in arm crank ergometry, synchronous hand cycling is less strenuous and more efficient than asynchronous hand cycling.     

Relation between preferred and optimal cadences during two hours of cycling in triathletes

Objectives

To determine whether the integrated electromyographic signal of two lower limb muscles indicates preferred cadence during a two hour cycling task.

Methods

Eight male triathletes performed right isometric maximum voluntary contraction (MVC) knee extension and plantar flexion before (P1) and after (P2) a two hour laboratory cycle at 65% of maximal aerobic power. Freely chosen cadence (FCC) was also determined, also at 65% of maximal aerobic power, from five randomised three minute sessions at 50, 65, 80, 95, and 110 rpm. The integrated electromyographic signal of the vastus lateralis and gastrocnemius lateralis muscles was recorded during MVC and the cycle task.

Results

The FCC decreased significantly (p<0.01) from P1 (87.4 rpm) to P2 (68.6 rpm), towards the energetically optimal cadence. The latter did not vary significantly during the cycle task. MVC of the vastus lateralis and gastrocnemius lateralis decreased significantly (p<0.01) between P1 and P2 (by 13.5% and 9.6% respectively). The results indicate that muscle activation at constant power was not minimised at specific cadences. Only the gastrocnemius lateralis muscle was affected by a two hour cycling task (especially at 95 and 110 rpm), whereas vastus lateralis remained stable.

Conclusion

The decrease in FCC observed at the end of the cycle task may be due to changes in the muscle fibre recruitment pattern with increasing exercise duration and cadence.     

Effect of cycling cadence on contractile and neural properties of knee extensors.

PURPOSE: This study investigated the effect of prior prolonged cycling exercise performed at different cadences on subsequent neuromuscular characteristics. METHODS: Eight well-trained triathletes sustained 80% of their maximal aerobic power during 30 min at three cadences: the freely chosen cadence (FCC), FCC-20%, and FCC+20%. Maximal isometric and concentric (120 degrees x s(-1) and 240 degrees x s(-1)) torques were recorded before and after the exercise. Central activation, neural (M-wave), and contractile (isometric muscular twitch) parameters of quadriceps muscle were also analyzed by electrical stimulation of the femoral nerve. RESULTS: Reductions in maximal isometric (P < 0.01) and concentric torques at 120 degrees x s(-1) (P < 0.05) were found after exercise. Central activation levels fell significantly (P < 0.05) by 13-16% depending on the pedaling rate. Although the M-wave did not significantly change after exercise, the ratio EMG RMS/M-wave amplitude decreased significantly (P < 0.01) on both vastus lateralis and vastus medialis muscles for FCC-20% and FCC but not for FCC+20%. Significant decreases in maximal twitch tension (P < 0.01), maximal rate of twitch development (P < 0.01), and time to half relaxation (P < 0.01) were observed postexercise with no effect of cadence. CONCLUSIONS: These findings suggest that force reduction after prolonged cycling is attributable to both central and peripheral factors but is not influenced by the pedaling rate in a range of FCC +/- 20%.     

Ventilatory responses during experimental cycle-run transition in triathletes.

PURPOSE AND METHODS: To determine the effects of cycling on a subsequent triathlon run, nine male triathletes underwent four successive laboratory trials: 1) an incremental treadmill test, 2) an incremental cycle test, 3) 30 min of cycling followed by 5 km of running (C-R), and 4) 30 min of running followed by 5 km of running (R-R). Before and 10 min after the third and fourth trials, the triathletes underwent pulmonary function testing including spirometry and diffusing capacity testing for carbon monoxide (DL(CO)). During the C-R and R-R trials, arterialized blood samples were obtained to measure arterial oxygen pressure (PaO2). During all trials, ventilatory data were collected every minute using an automated breath-by-breath system. RESULTS: The results showed that 1) the oxygen uptake (VO2) observed during subsequent running was similar for the C-R and R-R trials; 2) the ventilatory response (VE) during the first 8 min of subsequent running was significantly greater in the C-R than in R-R trial (P < 0.05); 3) only the C-R trial induced a significant increase (P < 0.05) in residual volume (RV), functional residual capacity (FRC), and the ratio of residual volume to total lung capacity (RV/TLC); and 4) although a significant decrease (P < 0.05) in DL(CO) was noted after C-R, no difference between the two exercise trials was found for the maximal drop in PaO2. CONCLUSIONS: We concluded that 1) the C-R trial induced specific alterations in pulmonary function that may be associated with respiratory muscle fatigue and/or exercise-induced hypoxemia, and 2) the greater VE observed during the first minute of running after cycling was due to the specificity of cycling. This reinforces the necessity for triathletes to practice multi-trial training to stimulate the physiological responses experienced during the swim-cycle and the cycle-run transitions.     

Drafting during swimming improves efficiency during subsequent cycling

PURPOSE: The aim of the present study was to investigate the effects of drafting (i.e., swimming directly behind a competitor) while swimming with a wet suit on physiological parameters and cadence during subsequent cycling. METHODS: Eight well-trained male triathletes underwent two submaximal sessions conducted in a counterbalanced order. One of these sessions (SAC) consisted of a 750-m swim, performed at competition pace, followed by a 15-min ride on a bicycle ergometer at 75% of maximal aerobic power and at a freely chosen cadence. During the other session (SDC) the subjects swam 750 m in a drafting position at the same pace as during SAC and then performed the 15-min cycling test at the same intensity as during SAC. RESULTS: The main result indicated that cycling efficiency was significantly improved when the cycling session was preceded by a swimming bout performed in drafting position compared with an isolated swimming bout (+4.8%, P < 0.05). CONCLUSION: These results could be partly explained by the lower relative intensity observed during swimming in the SDC trial when compared with the SAC trial. This study suggests the relative importance of swimming condition and highlights the advantage of drafting during the swimming portion of a sprint triathlon.     

Energy expenditure of submaximal running does not increase after cycle-run transition

AIM: This study was performed to determine the relationship between increased fat oxidation and decreased running efficiency following intense cycling exercise. METHODS: Twenty-two middle-level triathletes were studied during submaximal running before and after submaximal cycling exercise. All subjects completed a 13-min run on a track at a velocity corresponding to 75% of their maximal aerobic speed (MAS) before (T1) and after (T2) submaximal cycling exercise at 75 % of maximal aerobic power (MAP). The energy cost of running (Cr) was quantified using the O(2) uptake (.VO(2)) and energy expenditure (EE) using the respiratory exchange ratio (RER). Gas exchange was measured over 30 s during the 3(rd) min and last 30 s of each run. RESULTS: The results show that after cardiorespiratory equilibration (12 min 30 s), Cr (calculated in mL(O(2))*kg(-1)*m(-1)) during T2 was higher than during T1 (+ 8.2+/-4.3%; P = 0.03). Similar observations were made for .VO(2) (+ 8.2+/-4.3%; P = 0.03) and pulmonary ventilation (+ 7.0+/-12.3%; P = 0.04). RER decreased between T1 and T2 (- 8.6+/-9.2 %; p = 0.01). EE and Cr expressed in kJ.kg(-1).m(-1) did not vary significantly between T1 and T2. CONCLUSION: We suggest that the decrease in RER drop may be a result of greater lipid oxidation as metabolic substrate after cycling exercise.     

In professional road cyclists, low pedaling cadences are less efficient

PURPOSE: To determine the effects of changes in pedaling frequency on the gross efficiency (GE) and other physiological variables (oxygen uptake (VO2), HR, lactate, pH, ventilation, motor unit recruitment estimated by EMG) of professional cyclists while generating high power outputs (PO). METHODS: Following a counterbalanced, cross-over design, eight professional cyclists (age (mean +/- SD): 26 +/- 2 yr, VO2max: 74.0 +/- 5.7 mL x kg x min) performed three 6-min bouts at a fixed PO (mean of 366 +/- 37 W) and at a cadence of 60, 80, and 100 rpm. RESULTS: Values of GE averaged 22.4 +/- 1.7, 23.6 +/- 1.8 and 24.2 +/- 2.0% at 60, 80, and 100 rpm, respectively. Mean GE at 100 rpm was significantly higher than at 60 rpm (P < 0.05). Similarly, mean values of VO2, HR, rates of perceived exertion (RPE), lactate and normalized root-mean square EMG (rms-EMG) in both vastus lateralis and gluteus maximum muscles decreased at increasing cadences. CONCLUSIONS: In professional road cyclists riding at high PO, GE/economy improves at increasing pedaling cadences.     

Performance at high pedaling cadences in well-trained cyclists

PURPOSE: This study was conducted to determine the effect of high pedaling cadences on maximal cycling power output (W(max)). METHODS: Nine well-trained cyclists performed a continuous, incremental cycle-ergometer test to exhaustion (25 W increases every 3 min) either at 80, 100, or 120 rpm on three different occasions. RESULTS: W(max) was approximately 9% lower during 120 rpm in comparison with 80 and 100 rpm (335 +/- 9, 363 +/- 7, and 370 +/- 12 W, respectively; P < 0.05). During 120 rpm, ventilation rate (V(E)) increased above the increases in expired CO(2), which reduced the power output (PO) at the ventilatory anaerobic threshold (VT(2)) by 11% (P < 0.05). Gross efficiency (GE) did not differ among trials. At 120 rpm, capillary blood lactate concentration ([Lac]) increased above the 80-rpm trial (5.3 +/- 1.2 vs 3.0 +/- 0.7 mM at 300 W; P < 0.05), although pH was not reduced. At 120 rpm, expired CO(2) increased and reduced blood bicarbonate concentration ([HCO(3)(-)]) was reduced, maintaining blood pH similar to the other trials. CONCLUSION: A high pedaling cadence (i.e., 120 rpm) reduces performance (i.e., W(max)) and anaerobic threshold during an incremental test in well-trained cyclists. The data suggest that ventilatory anaerobic threshold (VT(2)) is a sensitive predictor of optimal pedaling cadence for performance, whereas blood pH or efficiency is not.     

Load and velocity of contraction influence gross and delta mechanical efficiency.

The effects of three different cadences and five different work rates on Gross (GE) and Delta Efficiency (DE) during cycle ergometry were studied. Fifteen well-trained cyclists exercised for 30 minutes at 60, 80, or 100 RPM on three different occasions. On each occasion, the load was increased every five minutes and corresponded to approximately 50, 60, 70, 80 and 90% of VO2max. During the last three minutes of each stage, steady-state energy expenditure was calculated while work rate was recorded. In addition, the oxygen cost of unloaded cycling (CUC) was also measured. GE was calculated as the ratio of work rate to the rate of energy expenditure, whereas DE was calculated as the reciprocal of the slope of this relationship at work rates between 50 and 90% of VO2max. The CUC corresponded to 0.66 +/- 0.03 l/min, 0.77 +/- 0.04 l/min and 1.04 +/- 0.04 l/min at 60 RPM, 80 RPM and 100 RPM, respectively (p less than 0.01 for all comparisons). GE was similar at all cadences when cycling at 80 and 90% VO2max. DE increased with increasing rpm and corresponded to 20.6 +/- 0.4%, 21.8 +/- 0.6%, and 23.8 +/- 0.4% at 60 RPM, 80 RPM and 100 RPM, respectively (p less than 0.01 for all comparisons). Therefore, when trained cyclists exercise intensely (80-90% VO2max), GE is similar at cadences of 60, 80 and 100 RPM, despite the significant increase in the CUC. Thus, it is possible that delta efficiency increases with increasing cadence.     

Effect of cycling experience and pedal cadence on the near-infrared spectroscopy parameters

PURPOSE: Previously we demonstrated that the method to reorder near-infrared spectroscopy (NIRS) parameters against crank angle could serve as a useful measure in providing circulatory dynamics and metabolic changes in a working muscle during pedaling exercise. To examine further applicability of this method, we investigated the effects of cycling experience and pedal cadence on the NIRS parameters. METHODS: Noncyclists (NON), triathletes (TRI), and cyclists (CYC) performed pedaling exercises at a work intensity of 75% VO2max while changing pedal cadence (50, 75, 85, and 95 rpm). Physiological and biomechanical responses and NIRS parameters were measured. RESULTS: NIRS measurements determined with the reordered NIRS change demonstrated significant differences depending on the factors. The bottom peak of reordered NIRS changes in muscle blood volume and oxygenation level shifted upward with an increase in pedal cadence in NON but remained unchanged in CYC. The reordered NIRS change demonstrated a temporary increase at the crank angle corresponding to the relaxation phase of the working muscle. This temporary increase was observed even in the highest pedal cadence in CYC. The difference in levels between the peak of the temporary increase and the bottom peak of reordered NIRS change (LPB-diff) for CYC at 85 rpm was significantly larger than that for NON. The results with NIRS parameters corresponded to changes in pedal force and myoelectric activity during pedal thrust. CONCLUSIONS: The bottom peak level of the reordered NIRS changes and LPB-diff determined for blood volume are available to detect noninvasively the differences in circulatory dynamics and metabolic change during pedaling exercises performed at different pedal cadences and also to estimate the difference of physiological and technical developments for endurance cycling in athletes.