Greater effects of high- compared with moderate-intensity interval training on cardio-metabolic variables, blood leptin concentration and ratings of perceived exertion in obese adolescent females.

This study examined the effects of high- vs. moderate-intensity interval training on cardiovascular fitness, leptin levels and ratings of perceived exertion (RPE) in obese female adolescents. Forty-seven participants were randomly assigned to one of three groups receiving either a 1:1 ratio of 15 s of effort comprising moderate-intensity interval training (MIIT at 80% maximal aerobic speed: MAS) or high-intensity interval training (HIIT at 100% MAS), with matched 15 s recovery at 50% MAS, thrice weekly, or a no-training control group. The HIIT and MIIT groups showed improved (p < 0.05) body mass (BM), BMI Z-score, and percentage of body fat (%BF). Only the HIIT group showed decreased waist circumference (WC) (p = 0.017). The effect of exercise on maximal oxygen uptake (VO2max) was significant (p = 0.019, ES = 0.48 and p = 0.010, ES = 0.57, HIIT and MIIT, respectively). The decrease of rate-pressure product (RPP) (p < 0.05, ES = 0.53 and ES = 0.46, HIIT and MIIT, respectively) followed the positive changes in resting heart rate and blood pressures. Blood glucose, insulin level and the homeostasis model assessment index for insulin decreased (p < 0.05) in both training groups. Significant decreases occurred in blood leptin (p = 0.021, ES = 0.67 and p = 0.011, ES = 0.73) and in RPE (p = 0.001, ES = 0.76 and p = 0.017, ES = 0.57) in HIIT and MIIT, respectively. In the post-intervention period, blood leptin was strongly associated with %BF (p < 0.001) and VO2max (p < 0.01) in the HIIT and MIIT groups, respectively, while RPE was strongly associated with BM (p < 0.01) in the HIIT group. The results suggest that high-intensity interval training may produce more positive effects on health determinants in comparison with the same training mode at a moderate intensity.

A specific prediction equation is necessary to estimate peak oxygen uptake in obese patients with metabolic syndrome.

PURPOSE: The aims were to: (1) compare peak oxygen uptake ([Formula: see text]peak) predicted from four standard equations to actual [Formula: see text]peak measured from a cardiopulmonary exercise test (CPET) in obese patients with metabolic syndrome (MetS), and (2) develop a new equation to accurately estimate [Formula: see text]peak in obese women with MetS. METHODS: Seventy-five obese patients with MetS performed a CPET. Anthropometric data were also collected for each participant. [Formula: see text]peak was predicted from four prediction equations (from Riddle et al., Hansen et al., Wasserman et al. or Gläser et al.) and then compared with the actual [Formula: see text]peak measured during the CPET. The accuracy of the predictions was determined with the Bland-Altman method. When accuracy was low, a new prediction equation including anthropometric variables was proposed. RESULTS: [Formula: see text]peak predicted from the equation of Wasserman et al. was not significantly different from actual [Formula: see text]peak in women. Moreover, a significant correlation was found between the predicted and actual values (p < 0.001, r = 0.69). In men, no significant difference was noted between actual [Formula: see text]peak and [Formula: see text]peak predicted from the prediction equation of Gläser et al., and these two values were also correlated (p = 0.03, r = 0.44). However, the LoA95% was wide, whatever the prediction equation or gender. Regression analysis suggested a new prediction equation derived from age and height for obese women with MetS. CONCLUSIONS: The methods of Wasserman et al. and Gläser et al. are valid to predict [Formula: see text]peak in obese women and men with MetS, respectively. However, the accuracy of the predictions was low for both methods. Consequently, a new prediction equation including age and height was developed for obese women with MetS. However, new prediction equation remains to develop in obese men with MetS.

Validity and reliability of the session-RPE method for quantifying training load in karate athletes.

AIM: To test the construct validity and reliability of the session rating of perceived exertion (sRPE) method by examining the relationship between RPE and physiological parameters (heart rate: HR and blood lactate concentration: [La --] ) and the correlations between sRPE and two HR--based methods for quantifying internal training load (Banister's method and Edwards's method) during karate training camp. METHODS: Eighteen elite karate athletes: ten men (age: 24.2 ± 2.3 y, body mass: 71.2 ± 9.0 kg, body fat: 8.2 ± 1.3% and height: 178 ± 7 cm) and eight women (age: 22.6 ± 1.2 y, body mass: 59.8 ± 8.4 kg, body fat: 20.2 ± 4.4%, height: 169 ± 4 cm) were included in the study. During training camp, subjects participated in eight karate--training sessions including three training modes (4 tactical--technical, 2 technical--development, and 2 randori training), during which RPE, HR, and [La -- ] were recorded. RESULTS: Significant correlations were found between RPE and physiological parameters (percentage of maximal HR: r = 0.75, 95% CI = 0.64--0.86; [La --] : r = 0.62, 95% CI = 0.49--0.75; P < 0.001). Moreover, individual sRPE was significantly correlated with two HR--based methods for quantifying internal training load ( r = 0.65--0.95; P < 0.001). The sRPE method showed the high reliability of the same intensity across training sessions (Cronbach's α = 0.81, 95% CI = 0.61--0.92). CONCLUSION: This study demonstrates that the sRPE method is valid for quantifying internal training load and intensity in karate.

[Blood lactate three minutes after a graded exercise test: a criterion of maximal exercise in patients with COPD]. / Lactatémie trois minutes après une EFX : un critère de maximalité chez le patient BPCO.

INTRODUCTION: The graded exercise test (GXT) is used to measure the exercise capacity of patients with chronic obstructive pulmonary disease (COPD). To do this GXT must be maximal (exhaustive). However, the value of the blood lactate at the GXT endpoint [La(-)max] or after a recovery period of three minutes [La(-)recovery], to confirm that the GXT is maximal, remains controversial. The purpose of the present study is to determine a threshold of [La(-)max] and/or [La(-)recovery], which confirms the exhaustiveness of GXT in patients with COPD. METHODS: Thirty-six patients with COPD performed a GXT until exhaustion on a cycle ergometer. During the GXT cardiorespiratory parameters, [La(-)max] and [La(-)recovery] were measured. When at least three out of five of the most frequently used criteria to confirm exhaustion were met, GXT was considered as maximal. Conversely, GXT was considered as sub-maximal when less three criteria were observed. The receiver operating characteristic (ROC) curves were analyzed. RESULTS: For [La(-)max] the areas under the ROC curve and the areas under the diagonal were not significantly different (P=0.16). For [La(-)recovery] the ROC curve inflected itself at 5.8mmol/L (sensitivity=0.92 and specificity=0.56). CONCLUSIONS: It was not possible to use [La(-)max] to confirm exhaustion in our population. However, [La(-)recovery]<5.8mmol/L may help to confirm non-exhaustion during GXT in patients with COPD. Below this blood lactate threshold 93% patients performed a sub-maximal GXT.

Relevance of the measure of perceived exertion for the rehabilitation of obese patients.

The most common tool used for measuring effort perception is the rating scale of perceived exertion (RPE) developed by Borg. This scale is also used for various outcomes in the general population. The validity and reliability of this scale have already been reported in obese patients. However, the relevance of measuring perceived exertion in obese patients is still poorly known. This review of the literature presents the Borg RPE scale (i.e., validity, reliability and recommendations) and its main advantages during graded exercise tests (e.g., comparison of physical capacity, predicting physiological variables, verifying exhaustion and exercise safety) and rehabilitation programs (e.g., individualized exercise intensity, evaluation of the impact of a rehabilitation program and even determining the perceptual preference) in obese patients. This review of the literature underlines the relevance and usefulness of the Borg RPE scale, which is still underused in obese patients. However, additional studies are still necessary before using this scale routinely in all obese patients (regardless of the severity of their obesity or associated complications).

Knowledge of the endpoint: effect on perceptual values.

The main purpose of this study was to examine the influence of knowledge of running length (i.e., duration or distance), or the lack of it (unknown endpoint) on the ratings of perceived exertion and estimated time to exhaustion. Fourteen men were recruited for this study. Participants performed 3 tests of a similar intensity (90 % maximal aerobic velocity) and length (100 % Tlim/Dlim). However, the exercise length was differently expressed. This was either unknown or defined in terms of duration or distance. The tests with a known length were performed in a counterbalanced order. During the tests, ratings of perceived exertion, estimated time to exhaustion, and heart rate were measured then compared by using 2-way analysis of variance for repeated measures. The results show that the ratings of perceived exertion, estimated time to exhaustion, and heart rate increased significantly with exercise duration (p < .001). Moreover, the ratings of perceived exertion were significantly different between the test with an unknown running endpoint and that with a known running distance at 40, 60 and 80 % Tlim (p < .05). Therefore, athletes perceived the run as being easier during the test with an unknown running endpoint compared to the test with a known running distance. Consequently, knowledge of running length influenced the ratings of perceived exertion probably due to teleoanticipation.

[Effects of intermittent walk program on the body mass and composition in obese women]. / Effets d'un programme de marche intermittente sur la masse et la composition corporelles de femmes obèses.

UNLABELLED: The obese patients adhere weakly to rehabilitation programs; therefore the expected gains are often disappointing. This is possibly linked to the monotony of constant velocity exercises frequently proposed. Consequently, other less monotonous exercises such as the intermittent walk may be more appropriated. OBJECTIVES: The main objectives of this study were to determine if the obese women prefer a constant velocity walk or an intermittent walk, and to analyze the effects of a rehabilitation program based on the intermittent walk. MATERIALS AND METHODS: Twenty obese women were recruited. To determine the preferred walk modality, 10 obese women performed a constant velocity walk and an intermittent walk (with a similar duration and velocity) on a treadmill. The preferred walk modality was determined by lower ratings of perceived exertion. Then, these same 10 women participated in a rehabilitation program of 10 weeks (three days per week) consisting of intermittent walks. The 10 other women did not participate in a training program. RESULTS: The ratings of perceived exertion were not significantly different between the two walk modalities. However, the women who participated in a training program increased their maximal distance during a 6 min walking test and they have stabilized theirs anthropometric data. Meanwhile, the untrained women have increased their body mass, body mass index and percentage of body fat. CONCLUSION: The obese patients preferred similarly the constant velocity walk and the intermittent walk, and a rehabilitation program based on an intermittent walk is effective in avoiding the obesity aggravation.

Influence of instructions on perceptually-based ratings.

The purpose of this study was to examine the influence of the expected running duration or distance on ratings of perceived exertion (RPE) and estimated time limit (ETL) values. Thirty-nine males performed an incremental test to measure their maximal aerobic velocity (MAV). Then, the subjects realised a constant velocity test (90 % MAV) to determine their time limit (Tlim) and distance limit (Dlim). Three homogenous groups were made up. Subsequently, all the groups performed 2 similar tests: a test at 90 % MAV for 80 % Tlim and a test at 90 % MAV for 80 % Dlim, each group with different instructions: group 1 (G1) was expected to maintain the velocity for 60 % Tlim (and Dlim), while group 2 (G2) and group 3 (G3) received instructions to maintain this velocity for 80 and 100 % Tlim (and Dlim), respectively. During these tests, RPE and ETL values were collected and compared by using a three-way repeated measures ANOVA. The statistical analysis revealed no significant group or test effect on RPE and ETL (p > .05). As a consequence, in this present study, it seems that the exercise instructions have not influenced significantly the hardness of effort (i.e., RPE) and the subjective estimation of endurance (i.e., ETL).

Validity and reliability of perceptually-based scales during exhausting runs in trained male runners.

The purposes of this study were to test the validity of a recent scale based on the estimation of a time of exhaustion (entitled Estimated Time Limit scale) to predict a time limit (Tlim) and to regulate exercise intensity and to investigate the reliability of the Estimated Time Limit scale and the Ratings of Perceived Exertion (RPE) scale. 14 male runners performed one incremental test, one constant velocity test at 85% of Maximal Aerobic Velocity (MAV), one constant duration test and one retest of 15 min. on an outdoor track. The difference between Estimated Time Limit values obtained during the incremental test at 85% MAV and measured Tlim values during the constant velocity test were examined, the velocities at ETL = 13 (i.e., 15 min.) obtained during the incremental test were compared with measured velocities during the constant duration test or the retest (only the best performance was used), and RPE and Estimated Time Limit values during the constant duration test were compared with those measured during retest. The results have shown a nonsignificant correlation between Estimated Time Limit values at 85% MAV and measured Tlim values during constant velocity test. There was a significant correlation (p < .02, r = .64) between velocities at ETL= 13 and measured velocities. However, the slope and y intercept value of this regression were significantly different from those of the identity line. There was no significant difference between constant duration test and retest for the values of RPE and Estimated Time Limit with high correlations (between r = .77 and .99 for RPE scale, and r = .74 and .99 for Estimated Time Limit scale). Moreover, the regression lines were close to the identity line. The RPE and Estimated Time Limit scales are reliable, but the lack of validity for the Estimated Time Limit scale suggests that more studies must be performed before using this scale to predict Tlim and regulate exercise intensity in male runners.