Indicator Of Exercise Intensity Research Articles

Accuracy of wrist-worn wearable devices for determining exercise intensity.

ObjectiveAs an indicator of exercise intensity, heart rate can be measured in a timely manner using wrist-worn devices. No study has attempted to estimate a target exercise intensity using wearable devices. The objective of the study was to evaluate the validity of prescribing exercise intensity using wrist-worn devices.MethodsThirty healthy subjects completed a maximal cardiopulmonary exercise test. Their heart rates were recorded using an electrocardiogram and two devices—Apple Watch Series 6 and Garmin Forerunner 945. Exercise intensity with the target heart rate was defined as resting heart rate + (maximal heart rate − resting heart rate) *n% (n%: 40–60% for moderate-intensity exercise and 60–89% for vigorous-intensity exercise). Heart rate was analyzed at the lower and upper limits of each exercise intensity (HR40, HR60, and HR89). The mean absolute percentage error and concordance correlation coefficient were calculated, and Bland–Altman plots and scatterplots were constructed.ResultsBoth devices showed a low mean absolute error (1.16–1.48 bpm for Apple and 1.35–2.25 for Garmin) and mean absolute percentage error (<1% for Apple and 1.16–1.39% for Garmin) in all intensities. A substantial correlation with electrocardiogram-measured heart rate was observed for moderate to vigorous intensity with concordance correlation coefficient > 0.95 for both devices, except that Garmin showed moderate correlation at the upper limit of vigorous activity with concordance correlation coefficient = 0.936. Moreover, Bland–Altman plots and scatterplots demonstrated a strong correlation without systematic error when the values obtained via the two devices were compared with electrocardiogram measurements.ConclusionsOur findings indicate the high validity of exercise prescriptions based on the heart rate measured by the two devices. Additional research should explore other populations to confirm these findings.

Biomarcadores de actividad física y el deporte

Biomarkers measure the body's adaptation to physical training through variations in blood concentrations. These modifications can be benign and reversible or negative, hence the importance of studying their implications. Lactate is an indicator of exercise intensity through the variation of its blood concentration, which increases in more intense exercise. In low intensity exercise, lactate and glucose concentrations gradually decrease, because they use fatty acids as the predominant energy source before glycolysis. High lactate concentrations favor the colonization of Veillonella at intestinal level, improving running time by the metabolic conversion of lactate to propionate and its disposition as an energy source directly, without the effect of first hepatic passage. Troponin is specific for diagnosing cardiac injury. It increases asymptomatically after intense training, proportional to the time and intensity of training. The post-exercise increase is greater in less trained athletes, in athletes adapted to high-intensity intermittent exercise, it rises significantly after intermittent exercise and not after continued exercise, evidencing the a Biomarkers measure the body's adaptation to physical training through variations in blood concentrations. These modifications can be benign and reversible or negative, hence the importance of studying their implications. Lactate is an indicator of exercise intensity through the variation of its blood concentration, which increases in more intense exercise. In low intensity exercise, lactate and glucose concentrations gradually decrease, because they use fatty acids as the predominant energy source before glycolysis. High lactate concentrations favor the colonization of Veillonella at intestinal level, improving running time by the metabolic conversion of lactate to propionate and its disposition as an energy source directly, without the effect of first hepatic passage. Troponin is specific for diagnosing cardiac injury. It increases asymptomatically after intense training, proportional to the time and intensity of training. The post-exercise increase is greater in less trained athletes, in athletes adapted to high-intensity intermittent exercise, it rises significantly after intermittent exercise and not after continued exercise, evidencing the adaptation of the organism to a specific type of exercise. There are typical post-exercise biochemical alterations, characterized by an increase in total creatine kinase and its fractions. It occurs after strenuous exercise that can cause muscle overload, muscle fiber rupture and inflammation, releasing these biochemical markers into the bloodstream. Different high-intensity and high-performance sports disciplines produce increased lactate dehydrogenase indicating risk of injury due to deterioration of muscle fibers.daptation of the organism to a specific type of exercise. There are typical post-exercise biochemical alterations, characterized by an increase in total creatine kinase and its fractions. It occurs after strenuous exercise that can cause muscle overload, muscle fiber rupture and inflammation, releasing these biochemical markers into the bloodstream. Different high-intensity and high-performance sports disciplines produce increased lactate dehydrogenase indicating risk of injury due to deterioration of muscle fibers. Received for review: August 2021Accepted for publication: October 2021Correspondence: 8 de octubre 3020. C.P.11600. Montevideo, Uruguay. Tel: (+598) 24876666 ext. 1663. Contact e-mail: vortizalfonzo@gmail.com

Cold temperature does not affect perceived exertion in males and females during submaximal cycling

Background: Perceived exertion is an acknowledged indicator of exercise intensity and homeostasis disturbance of an individual, however, there are few studies that have examined the influence of cold temperatures on perceived exertion measurements. Cognition is crucial to perception and exposure to cold temperatures can elicit decrements in cognition. Aims &amp; Objectives: The aim of this study was to determine if, and to what extent, exposure to cold environments may influence perceived exertion and cognitive ability. Study Design: Randomised controlled trial. Materials &amp; Methods: Sixteen participants (m= 8, f= 8, age: 22.3 ± 1.7 years (mean ± SD)), completed two trials in a randomised order in COLD (5°C) and CONTROL (18 °C, 55% relative humidity) conditions. During each trial, following a standardised warm up, participants performed a 6-minute cycle ergometer submaximal exercise. Cognitive ability was assessed pre and post exercise with a reaction time (RT) test. Participant’s physiological responses were measured using Rate of Perceived Exertion (RPE), Heart Rate (HR), Oxygen consumption (VO2), Minute Ventilation (VE), Tympanic (Tt) and Skin Temperature (Tsk) continuously during testing. Statistics: Two-way repeated measures Analysis of Variances (ANOVA), were between environmental conditions over time. Data are reported as mean (M) ± standard deviation (SD). Ordinal Friedman ANOVA tests were conducted on RPE data between environmental conditions and gender. Non-parametric descriptive statistics were reported as medians (Mdn) and inter-quartile ranges (IQR) (25th – 75th Percentile). Statistical significance was accepted at p &lt; 0.05. Results: There was no significant difference (p &gt; 0.05) reported in RPE, VO2 and VE between COLD and CONTROL groups, however, significant decreases in Tsk (p = 0.001) and Tt (p = 0.001) were observed in COLD compared to CONTROL groups. Additionally, no significant differences (p &gt; 0.05) in RT occurred between COLD and CONTROL. Furthermore, no significant differences in RPE were established between genders. Conclusions: Short-term exposure to cold temperatures does not significantly affect physical exertion perception or cognitive ability.

Exercise Prescription Techniques in Cardiac Rehabilitation Centers in Midwest States

ABSTRACTIntroduction: Cardiac rehabilitation (CR) is a primary prescribed treatment for a variety of cardiovascular disease states, including: coronary artery disease, percutaneous coronary intervention (PCI), coronary artery bypass graft (CABG), myocardial infarction (MI), and heart failure. For this reason, exercise prescription guidelines for cardiac patients have been established. However, it is unclear how these guidelines are being administered at cardiac rehabilitation centers. The purpose of this study is to assess current exercise prescription techniques at cardiac rehabilitation clinics across several Midwest states in the United States.Methods: Fifty-eight CR programs from Michigan, Indiana, Illinois, Minnesota, Wisconsin, and Ohio were administered a questionnaire assessing clinic characteristics, aerobic and resistance exercise prescription techniques.Results: Most reported patient types were PCI, CABG, and MI. Clinical exercise physiologists were the primary exercise prescription writers (81%). Only 32% of the clinics required a clinical certification. Baseline stress tests prior to CR were performed in 33% of programs. Rating of Perceived Exertion (RPE) was the most commonly used indicator of exercise intensity, followed by heart rate reserve (HRR), and METs. Resistance exercise was practiced in 89% of CR programs. The most common intensity indicator was trial and error, and RPE.Conclusion: Results demonstrate exercise prescription variability among CR programs. This emphasizes the complexity and expertise among clinical exercise physiologists. These results also highlight the importance that academic programs place on training students across all prescription techniques, and utilization of research-based prescription guidelines published by professional organizations.

Changes of muscle oxygenation and blood lactate concentration of swimming athletes during graded incremental exercise

The sport performance of swimming athletes in three different levels including 5 national high-level swimming athletes, 5 ordinary swimming athletes and 5 college students was investigated by near-infrared spectroscopy (NIRS). Four parameters of muscle oxygenation and blood lactate (BLa) concentration were simultaneously monitored during incremental exercise on the ergometer. It was found that inflection points of muscle oxygenation and BLa concentration were consistent with the human sport capacity. Moreover, inflection points of muscle oxygenation occurred earlier than those of BLa concentration in ordinary athletes and college students. It implies monitoring changes of muscle oxygenation is superior to BLa measurement under this condition, since BLa test has an unavoidable time lag. Significant correlation (r 2 = 0.948; P<0.05) was observed between inflection points of muscle oxygenation difference and inflection points of BLa concentration on workload. This relationship suggests changes of muscle oxygenation detected by NIRS is beneficial to the evaluation of athletes’ physiologic function and training load. Considering that muscle oxygenation could be in-vivo and non-invasively measured by NIRS, it may be a better indicator of exercise intensity than BLa measurement in the near future.

Carbohydrate and lactate utilisation during exercise with and without Yerba Maté ingestion

Nutritional ergogenic and thermogenic aids are commonly used to optimise carbohydrate utilisation and potentially enhance glycogen-sparing ability. However, less is known about the potential effects during exercise, particularly on the responses of carbohydrate oxidation (CHO) and blood lactate concentration (BLC), which are known indicators of exercise intensity and determine exercise performance. This study investigated whether the potential thermogenic effects of Yerba Mate (YM), the plant of (Illex Paraguariensis), affect carbohydrate oxidation rate (CHO) and BLC levels during low and moderate intensity exercise. Male and female participants (n= 11) ingested either 1 g of YM or placebo capsules (PLA) in a randomised crossover experimental design. Within laboratory conditions, participants rested for 1 hr before performing two incremental exercise ergometry tests in separate visits with the power output being initiated and increased by 0·5 W.kg−1 of body mass every 3 min stage until exhaustion. Cardiorespiratory measurements and indirect calorimetry technique were applied to analyse CHO and energy expenditure derived from carbohydrate (EEcho), and capillary blood samples were collected and analysed for BLC at rest and for each exercise intensity domain. Data were analysed using a repeated measures ANOVA design. CHO was reduced significantly (e.g. 0·37 ± 0·24 vs. 0·59 ± 0·19, 0·75 ± 0·24 vs. 1·00 ± 0·33 and 1·36 ± 0·48 vs. 1·64 ± 0·47 g.min−1 at 40, 50, 60 and 70% of VO2 peak respectively, P< 0·001, ANOVA main effects) in the YM compared with PLA at all sub-maximal exercise intensities up to the level of 70% of maximal oxygen uptake (VO2peak), which corresponded to reaching carbohydrate saturation level (respiratory exchange ratio = 1), (p< 0·001, ANOVA main effects). EECHO was also reduced in the YM compared with PLA (Table1). These effects were combined by a trend, though not significant towards a decrease in BLC (P= 0·07) at the same given exercise intensities in YM compared with PLA (Table 1).

Validity of Rating of Perceived Exertion Ranges in Individuals in the Subacute Stage of Stroke Recovery

Background: Rating of perceived exertion (RPE) is used to monitor or prescribe workload of exercise, but its utility among individuals with a stroke remains in question. Objective: To examine the validity of RPE at multiple percentages of peak aerobic capacity (Vo2peak) in individuals in the subacute stage of stroke recovery. Methods: Thirty-seven patients with stroke in the subacute stage of recovery from an inpatient rehabilitation institute completed a graded maximal exercise test on a semi-recumbent cycle ergometer. Respiratory gas exchange was monitored for analysis of Vo2, while heart rate and RPE (Borg CR10 Scale) were measured at the end of each minute. RPE was compared with expected ranges when at 60%, 70%, and 80% of Vo2peak. Post hoc analyses were performed to determine whether patient characteristics differed between participants who fell within and outside the expected RPE range at 80% of Vo2peak. Results: Median (interquartile range) RPE at 60%, 70%, and 80% Vo2peak were 3.0 (3.0-3.5), 3.0 (3.0-5.0), and 4.75 (3.0-5.75), respectively; 76.2%, 69.0%, and 38.9% of participants fell into the expected RPE range at each intensity. Patient characteristics were similar between participants who fell within and outside the expected RPE range at 80% Vo2peak. Conclusion: RPE appears to be a reasonable indicator of exercise intensity after stroke at moderate (60%-70% Vo2peak) but not high-intensity exercise (80% Vo2peak). This conclusion is based on the high degree of between-subject variability in RPE at 80% Vo2peak. Future research should identify whether RPE can be adapted to accurately capture exertion during high-intensity exercise after stroke.

Acute physiological responses to recreational in-line skating in young adults

We examined the physiological responses to in-line skating exercise at self-selected paces in recreationally trained adults. Seven men and 10 women performed in-line skating exercise during which oxygen uptake ([Vdot]O2) and heart rate (HR) were recorded continuously. Ratings of perceived exertion (RPE) and blood lactate concentration were also obtained at the end of exercise. Furthermore, subjects’ peak [Vdot]O2, peak HR, RPE and gas-exchange thresholds were determined in laboratory settings. The average exercise intensity during in-line skating was 90% of peak HR, 67% of peak [Vdot]O2, 84% of HR reserve and 64% of [Vdot]O2 reserve. When expressed as RPE and as metabolic equivalents (METs), the average exercise intensity was 13.1 RPE and 9.4 METs. Overall, these indicators of exercise intensity categorise in-line skating at self-selected paces as a vigorous physical activity. Notably, at similar [Vdot]O2 values, significantly higher HR (174±16 vs. 156±6 bpm; p<0.001) and RPE (13.1±1.4 vs. 11.7±1.4; p=0.019) were observed for in-line skating compared with treadmill running. We conclude that 1. recreational in-line skating induces physiological responses that are sufficient for improving and maintaining cardiovascular fitness in healthy adults, 2. HR- and RPE-based methods for quantifying the exercise intensity during in-line skating may overestimate the actual metabolic load and 3. the derivation of exercise prescriptions for in-line skating should be preferably based on specific (i.e. in-line skating) graded exhaustive exercise test.

Heart rate response to professional road cycling: the Tour de France.

The aim of the present investigation was to evaluate the heart rate response of 8 professional cyclists (26+/-3 yr; 68.9+/-5.2 kg; V02max: 74.0+/-5.8 ml x kg(-1) x min(-1)) during the 3-week Tour de France as an indicator of exercise intensity. Subjects wore a heart rate telemeter during 22 competition stages and recorded data were analysed using computer software. Two reference heart rates (corresponding to the first and second ventilatory thresholds or VT1 and VT2) were used to establish three levels of exercise intensity defined as phases I (<VT1), II (VT1 -VT2) and III (<VT2). The average total time spent by each subject in each of the 3 phases respectively was approximately 71, 23 and 8 h. The relative contributions of each phase were 70, 23 and 7%. The percentage relative contribution of each phase was significantly different (p<0.01) in each of the competition stages (time trials, flat stages, "high-mountain" stages and "medium-mountain" stages). Exercise intensity was particularly high during the time trials and high mountain stages. It may be concluded that during an endurance event such as the Tour de France, although the overall contribution of moderate (VT1 to VT2) or high intensity exercise (>VT2) is substantially lower than that of light, aerobic exercise (<VT1), a clear distinction must be made between the different type of stages (i.e. easy, flat parcours vs mountain stages or time trials) and the role of each cyclist in the team must be also considered.

Blood Lactate Measurements and Analysis during Exercise: A Guide for Clinicians

Blood lactate concentration ([La(-)](b)) is one of the most often measured parameters during clinical exercise testing as well as during performance testing of athletes. While an elevated [La(-)](b) may be indicative of ischemia or hypoxemia, it may also be a "normal" physiological response to exertion. In response to "all-out" maximal exertion lasting 30-120 seconds, peak [La(-)](b) values of approximately 15-25 mM may be observed 3-8 minutes postexercise. In response to progressive, incremental exercise, [La(-)](b) increases gradually at first and then more rapidly as the exercise becomes more intense. The work rate beyond which [La(-)](b) increases exponentially [the lactate threshold (LT)] is a better predictor of performance than V O2max and is a better indicator of exercise intensity than heart rate; thus LT (and other valid methods of describing this curvilinear [La(-)](b) response with a single point) is useful in prescribing exercise intensities for most diseased and nondiseased patients alike. H(+)-monocarboxylate cotransporters provide the primary of three routes by which La(-) transport proceeds across the sarcolemma and red blood cell membrane. At rest and during most exercise conditions, whole blood [La(-)] values are on average 70% of the corresponding plasma [La(-)] values; thus when analyzing [La(-)](b'), care should be taken to both (1) validate the [La(-)](b)-measuring instrument with the criterion/reference enzymatic method and (2) interpret the results correctly based on what is being measured (plasma or whole blood). Overall, it is advantageous for clinicians to have a thorough understanding of [La(-)](b) responses, blood La(-) transport and distribution, and [La(-)](b) analysis.

Heart Rate Response to Professional Road Cycling: The Tour de France

The aim of the present investigation was to evaluate the heart rate response of 8 professional cyclists (2:6±3 yr; 68.9±5.2 kg; VO2max: 74.0±5.8 ml·kg-1 min-1) during the 3-week Tour de France as an indicator of exercise intensity. Subjects wore a heart rate telemeter during 22 competition stages and recorded data were analysed using computer software. Two reference heart rates (corresponding to the first and second ventilatory thresholds or VT1 and VT2) were used to establish three levels of exercise intensity defined as phases I (<VT1), II (VT1 -VT2) and III (<VT2). The average total time spent by each subject in each of the 3 phases respectively was approximately 71, 23 and 8 h. The relative contributions of each phase were 70, 23 and 7 %. The percentage relative contribution of each phase was significantly different (p<0.01) in each of the competition stages (time trials, flat stages, „high-mountain” stages and „medium-mountain” stages). Exercise intensity was particularly high during the time trials and high mountain stages. It may be concluded that during an endurance event such as the Tour de France, although the overall contribution of moderate (VT1 to VT2) or high intensity exercise (> VT2) is substantially lower than that of light, aerobic exercise (< VT1), a clear distinction must be made between the different type of stages (i.e. easy, flat parcours vs mountain stages or time trials) and the role of each cyclist in the team must be also considered.

Post‐exercise palpation of pulse rates: its applicability to habitual exercisers

Despite the increased popularity of heart rate (HR) monitors, endurance-trained adults as well as habitual exercisers often use pulse rate palpation to periodically monitor exercise intensity. However, due to the rapid recovery of HR following exercise bouts, post-exercise palpation of pulse rates may underestimate exercise HR. To test this hypothesis, we studied 20 young physically active adults performing two sets of exercise for 5 min at 70% and 85% of maximal HR on the treadmill; one with carotid and another with radial pulse count. Post-exercise palpation of pulse rate was lower (P < 0.01) than the actual HR during exercise, underestimating exercise HR by 20-27 bpm (beats per min). Even when ECG tracings of HR were analyzed immediately after exercise (0-15 s), a significant underestimation of exercise HR (7-9 bpm) still persisted (P < 0.05). Following exercise, pulse rate obtained by carotid palpation at both intensities and radial palpation at the lower intensity was no different from the corresponding HR measured with ECG. In the radial artery trial at the higher exercise intensity, pulse rate following exercise was lower (10 bpm; P < 0.05) than ECG-derived HR. Arterial stiffness, which is closely associated with arterial baroreflex sensitivity, was not significantly related to the changes in HR with carotid palpation. We concluded that post-exercise pulse palpations may not be appropriate as an indicator of exercise intensity in habitual exercisers.

Post-Exercise Palpation of Pulse Rates

0066 Despite the intense marketing of heart rate (HR) monitors, endurance-trained adults as well as participants involved in group exercise settings (e.g., aerobic dancing) still rely on the palpation of pulse rates to periodically monitor exercise intensity. However, due to the rapid recovery of HR following exercise, post-exercise palpation of pulse rates may underestimate exercise HR in this population. Futhermore, because baroreceptor sensitivity is increased in endurance-trained individuals, carotid palpation may cause reflex reductions in heart rate. PURPOSE: To determine the accuracy of carotid and radial palpation in estimating exercise heart rate and the effect of carotid palpation on HR following exercise in an endurance-trained population. METHODS: Twenty young healthy endurance-trained adults (24±1 yr) performed two sets of submaximal exercises for five min at 70 and 85% of maximal HR on the treadmill; one with carotid pulse count and another with radial pulse count, in a randomized order. RESULTS: Post-exercise palpation of pulse rate was substantially lower (P<0.01) than the actual HR during exercise. On average, HR was underestimated by 20 and 27 beats per min at lower and higher intensities of exercise. Even when ECG-derived HR was analyzed immediately after exercise, a significant underestimation of exercise HR (seven to nine beats per min lower) still persisted (P<0.05). Pulse rate obtained by carotid palpation following exercise at both intensities and radial palpation at the lower intensity was no different from HR measured with ECG after exercise. In the radial artery trial at the higher exercise intensity, pulse rate following exercise was lower (P<0.05) than ECG-derived HR. Carotid palpation did not significantly affect HR following exercise at either exercise intensity. Augmentation index and pulse wave velocity, which are measures of arterial stiffness that are closely associated with arterial baroreflex sensitivity, were not significantly related to the changes in HR with carotid palpation. CONCLUSION: Post-exercise pulse counts may not be appropriate as an indicator of exercise intensity in endurance-trained adults. Supported by NIH Grant AG20966

Heart Rate Response to Volleyball Specific Training

1425 Heart rate (HR) response during exercise has been strongly used as indicator of exercise intensity as well as of the cardiopulmonary stress. Several works have reported the effects of physical training to reduce resting and exercise HR. PURPOSE: To evaluate the HR response to exercise during 3 weeks of specific physical volleyball training. METHODS: Twelve volleyball female players (15 ± 1yrs; 67.8 ± 6.4kg; 176 ± 5cm) were divided in 3 groups: Center attackers (C, n = 3), Setters (S, n = 3), and forward attackers (F, n = 6). Training concerned 15 sessions lasting 3h, and a rest period for 24h. Sessions were divided in 2 h of technical training, followed by 60min of physical training for C (reaction time, plyometry and coordination), S (speed and attack power) and F (plyometry). The HR was measured continuously at rest (at least 10 min seated) during training (Polar S610), and calculated mean (MHR) and peak HR (PHR) for each session. The HR was fitted by linear regression (least square method) and the coefficients were tested by x2 test. The MHR and PHR were compared by non-parametric analysis of variance (ANOVA), using α = 0.05. Additionally, PHR attained during training was modeled by linear regression and the angular coefficients (Ai) were tested by x2 test. RESULTS: The MHR and PHR showed a progressive reduction during training (p<0.05) attaining a mean decrease of 22 ± 5bpm (PHR) and 19 ± 6bpm (MHR) in all groups. No significant differences were achieved among positions S, F and C for MHR or PHR. Fitted functions resulted in significant (p<0.05) angular coefficients for all groups. No differences were attained among groups. CONCLUSIONS: The PHR and MHR shown a tendency to reduce after training which was evidenced by the negative angular coefficients. In summary, volleyball training showed a possible adaptation of cardiopulmonary system to stress.

Post-Exercise Palpation of Pulse Rates

0066 Despite the intense marketing of heart rate (HR) monitors, endurance-trained adults as well as participants involved in group exercise settings (e.g., aerobic dancing) still rely on the palpation of pulse rates to periodically monitor exercise intensity. However, due to the rapid recovery of HR following exercise, post-exercise palpation of pulse rates may underestimate exercise HR in this population. Futhermore, because baroreceptor sensitivity is increased in endurance-trained individuals, carotid palpation may cause reflex reductions in heart rate. PURPOSE: To determine the accuracy of carotid and radial palpation in estimating exercise heart rate and the effect of carotid palpation on HR following exercise in an endurance-trained population. METHODS: Twenty young healthy endurance-trained adults (24±1 yr) performed two sets of submaximal exercises for five min at 70 and 85% of maximal HR on the treadmill; one with carotid pulse count and another with radial pulse count, in a randomized order. RESULTS: Post-exercise palpation of pulse rate was substantially lower (P<0.01) than the actual HR during exercise. On average, HR was underestimated by 20 and 27 beats per min at lower and higher intensities of exercise. Even when ECG-derived HR was analyzed immediately after exercise, a significant underestimation of exercise HR (seven to nine beats per min lower) still persisted (P<0.05). Pulse rate obtained by carotid palpation following exercise at both intensities and radial palpation at the lower intensity was no different from HR measured with ECG after exercise. In the radial artery trial at the higher exercise intensity, pulse rate following exercise was lower (P<0.05) than ECG-derived HR. Carotid palpation did not significantly affect HR following exercise at either exercise intensity. Augmentation index and pulse wave velocity, which are measures of arterial stiffness that are closely associated with arterial baroreflex sensitivity, were not significantly related to the changes in HR with carotid palpation. CONCLUSION: Post-exercise pulse counts may not be appropriate as an indicator of exercise intensity in endurance-trained adults. Supported by NIH Grant AG20966

Preferred pedalling cadence in professional cycling.

The aim of this investigation was to evaluate the preferred cycling cadence of professional riders during competition. We measured the cadence of seven professional cyclists (28 +/- 1 yr) during 3-wk road races (Giro d'Italia, Tour de France, and Vuelta a España) involving three main competition requirements: uphill cycling (high mountain passes of approximately 15 km, or HM); individual time trials of approximately 50 km on level ground (TT); and flat, long ( approximately 190 km) group stages (F). Heart rate (HR) data were also recorded as an indicator of exercise intensity during HM, TT, and F. Mean cadence was significantly lower (P < 0.01) during HM (71.0 +/- 1.4 rpm) than either F and TT (89.3 +/- 1.0 and 92.4 +/- 1.3 rpm, respectively). HR was similar during HM and TT (157 +/- 4 and 158 +/- 3 bpm) and in both cases higher (P < 0.01) than during F (124 +/- 2 bpm). During both F and TT, professional riders spontaneously adopt higher cadences (around 90 rpm) than those previously reported in the majority of laboratory studies as being the most economical. In contrast, during HM they seem to adopt a more economical pedalling rate (approximately 70 rpm), possibly as a result of the specific demands of this competition phase.

Differentiated ratings of perceived exertion and physiological responses during aerobic dance steps by impact/type of arm movement.

Overall ratings of perceived exertion, i.e., undifferentiated RPE, are often used as indicators of exercise intensity during walking, jogging, and cycling; however, conflicting results concerning RPE during aerobic dance exercise have been reported, and the use of differentiated RPE, i.e., local RPE and central RPE, has not been investigated. The purposes of this study were to assess local, central, and over-all RPE, and physiological responses [heart rate (HR); % HRmax; absolute and relative VO2;% VO2 max, ventilation (VE), ventilatory equivalent (VE.VO2(-1); and oxygen pulse] during aerobic dance exercise varied by Arm Movement (Static Arm vs Dynamic Arm) and Impact (High vs Low). Trained women (N = 25; max VO2 = 50.4 +/- 7.5 ml.kg-1.min.-1) completed four aerobic dance steps. No RPE were significantly correlated with heart rate or VO2; however, for all steps all RPE were significantly (r = .40-.62) correlated with VE.VO2(-1) or VE. No interactions were present for RPE or physiological variables, and main effects were noted for Impact and Arm Movement. All RPE were greater for High Impact and for Static Arm Movement. Because VE and VE.VO2(-1) were correlated with Overall RPE for all steps, this may suggest that participants "attended to" perceived changes in respiratory phenomena during aerobic dance exercise. It appears that during combined arm-and-leg aerobic dance exercise the use of Overall RPE is sufficient to assess perceptual sensations associated with the intensity of the exercise. Changes in Overall RPE were proportionate to objective measures of exercise intensity, i.e., HR and VO2; however, it is recommended that both HR and Overall RPE be used to assess fully a participant's objective and subjective responses during aerobic dance exercise.

DIFFERENTIATED RATINGS OF PERCEIVED EXERTION AND PHYSIOLOGICAL RESPONSES DURING AEROBIC DANCE STEPS BY IMPACT/TYPE OF ARM MOVEMENT

Overall ratings of perceived exertion, i.e., undifferentiated RPE, are often used as indicators of exercise intensity during walking, jogging, and cycling; however, conflicting results concerning RPE during aerobic dance exercise have been reported, and the use of differentiated RPE, i.e., local RPE and central RPE, has not been investigated. The purposes of this study were to assess local, central, and over-all RPE, and physiological responses [heart rate (HR); % HRmax; absolute and relative VO2; % VO2 max, ventilation (VE), ventilatory equivalent (VE · VO2−1); and oxygen pulse] during aerobic dance exercise varied by Arm Movement (Static Arm vs Dynamic Arm) and Impact (High vs Low). Trained women (N = 25; max VO2 = 50.4± 7.5 ml · kg−1 · min.−1) completed four aerobic dance steps. No RPE were significantly correlated with heart rate or VO2; however, for all steps all RPE were significantly (r = .40–,62) correlated with VE · VO2−1or VE. No interactions were present for RPE or physiological variables, and main effects were noted for Impact and Arm Movement. All RPE were greater for High Impact and for Static Arm Movement. Because VE and VE · VO2−1 were correlated with Overall RPE for all steps, this may suggest that participants “attended to” perceived changes in respiratory phenomena during aerobic dance exercise. It appears that during combined arm-and-leg aerobic dance exercise the use of Overall RPE is sufficient to assess perceptual sensations associated with the intensity of the exercise. Changes in Overall RPE were proportionate to objective measures of exercise intensity, i.e., HR and VO2; however, it is recommended that both HR and Overall RPE be used to assess fully a participant's objective and subjective responses during aerobic dance exercise.

PERCEIVED EXERTION AND METABOLIC RESPONSES OF WOMEN DURING AEROBIC DANCE EXERCISE

The relationship between ratings of perceived exertion (RPE) and metabolic responses was examined during aerobic dance exercise with combined arm and leg movements. 16 women with previous aerobic dance instructional experience performed three consecutive trials of 8 min. each of aerobic dance exercise at a cadence of 124 and 138 beats.min.-1. Estimates of RPE reported at the end of each trial were significantly different across the trials while heart rate and % maximum heart rate were significantly different between Trials 1 and 3. Correlations and partial correlations between RPE and all metabolic variables were not significant across trials and with trials combined except for ventilation. Results indicated that RPE should not be used singularly as an indicator of exercise intensity during aerobic dance exercise.

Perceived Exertion and Metabolic Responses of Women during Aerobic Dance Exercise

The relationship between ratings of perceived exertion (RPE) and metabolic responses was examined during aerobic dance exercise with combined arm and leg movements. 16 women with previous aerobic dance instructional experience performed three consecutive trials of 8 min. each of aerobic dance exercise at a cadence of 124 and 138 beats • min.-1 Estimates of RPE reported at the end of each trial were significantly different across the trials while heart rate and % maximum heart rate were significantly different between Trials 1 and 3. Correlations and partial correlations between RPE and all metabolic variables were not significant across trials and with trials combined except for ventilation. Results indicated that RPE should not be used singularly as an indicator of exercise intensity during aerobic dance exercise.