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At least 847 records · Page 47Linked to original sources
PubMed1990

The effect of physical exertions on heart sensitivity to ischemia and metabolic conditioning of these changes.

With increasing duration of swimming exercise the heart becomes less sensitive to ischemia, as evaluated by the rate of development of ischemic contracture immediately after the exertion. This delay in the development of ischemic contracture was apparently due to metabolic changes directed to decrease the heart energy consumption in conditions where the capacity for glycolytic ATP production was decreased. A decrease in: 1) the amount of rapidly exchangeable Ca2+, which is bound to anionic sites on the sarcolemmal membrane and 2) the myofibrillar Ca2+ sensitivity seems to play an important role. Regular swimming exercise, which is characterized by a significant cardiac hypertrophy and enhanced heart glycogen content, increased the sensitivity of energy mobilizing processes to catecholamine action. These changes accelerated ATP depletion and the development of an irreversible injury when the heart was made ischemic after catecholamine stimulation. Obtained results together with data from literature underline the importance of regular testing of cardiac function, including echocardiography, in young sportsmen undergoing high-intensity training.

Adenosine Triphosphate↗
PubMed1999

A new rating scale of perceived exertion based on subjective estimation of exhaustion time: a preliminary study.

Perceived exertion has been investigated during incremental exercise to exhaustion with athletes, according to the 6-20 scale proposed by Borg (RPE, 1970) and a new scale based on the estimation of exhaustion time (t(lim)) (Estimated Time Limit or ETL, from 1 to 20; ETL= 21 - 2 n, with n = log2t(lim)). ETL increased linearly with the percentage of maximal aerobic power (%MAP) up to the ventilatory threshold (VT). Beyond VT, an inflection of the ETL-%MAP relationship was observed. RPE and ETL calculated at VT were equal to 15 +/- 1.7, i.e. an exercise intensity perceived as "hard", and 10 +/- 2.3, i.e. an estimated exhaustion time equal approximately to 45 minutes. Standard deviations for RPE and ETL at VT were too large for an accurate estimation of this threshold. The results of the present study suggest that RPE and ETL should be used in addition to physiological data, but not replace them in the prescription of a training program.

Adult↗
PubMed1998

The effect of training and epinephrine infusion on ratings of perceived exertion (RPE).

Seven untrained males (mean age [+/-SD] = 25.6+/-3.9 yr, mean ht = 177.0+/-5.9 cm, mean wt = 65.8+/-7.4 kg) completed a 6-week exercise program (cycle ergometer). Prior to training, and at the end of each week of training, each subject performed a 20 min constant-power exercise test (absolute power was the same each week). At the end of the six week training program (within a few days), an additional 20 min constant-power test was performed, during which epinephrine was infused at a rate of 100 ng x kg(-1) x min(-1) over the final 10 min of exercise. Training significantly (P<0.05) reduced end-exercise ratings of perceived exertion (RPE), plasma epinephrine concentration [Epi], plasma norepinephrine concentration [NE], blood lactate concentration [La-], minute ventilation (V(E)), heart rate (HR), and blood glucose concentration [Glc]. Epinephrine infusion failed to increase RPE despite significant (p < 0.05) increases in [Epi], [La-], V(E) and [Glc]. Therefore, the present data indicate that RPE during exercise is not causally related to changes in plasma [Epi]. It also appears that modest changes in plasma [NE], blood [La-], V(E) and blood [Glc] during constant-power cycle ergometry (as observed during Epi infusion) do not impact RPE.

Adrenergic Agonists↗
PubMed1999

[Injury and exertion patterns in football on artificial turf].

This controlled non-selected cross-sectional study supplies a basic survey on the topic analysing 1783 injuries in 433 of 736 athletes out of a closed collective. Aged 11 to 40 years and having played an average of 3.7 years an artificial turf the players had sustained 38% skin injuries (58% in the legs), 28% sprains (64% in the ankle joints, 21% in the knee joints) and 17% muscle injuries. 76% of all injuries were minor, i.e. leading to an interruption of under one week, only 8% were severe with a break of over 3 weeks. The average risk of injury was 6 per 1000 hours of participation, similar to that in football on natural grass. More than half of the players protocol pain in the joints, muscles or column persisting even one day after the game, which only led to medical assistance in 3% of all cases. Playing football on artificial grass displays a specific pattern of injuries and exertion syndromes without a higher rate or grade of injuries and therefore shows no medical need for restriction.

Adolescent↗
PubMed1987

Using perceived exertion to prescribe and monitor exercise training heart rate.

We examined whether feedback of heart rate (HR) or HR combined with ratings of perceived exertion (RPE and HR) during a graded exercise test (GXT) and during early trials of field training would reduce the errors commonly seen when training heart rate range (THR) is self-monitored by participants. Asymptomatic males (n = 24) were tested on a Balke treadmill protocol in a randomized, between-groups design under control conditions or conditions where feedback about HR or HR combined with RPE were given as age-predicted THR was approximated. This was followed on alternating days by three field trials of an 800-m jog where errors between prescribed and attained THR were fed back to each subject. A priori 95% confidence intervals for the first field trial showed that signed (algebraic) error for the HR combined with RPE condition (+3 bts/min) was less than for controls (+23.5 bts/min). Feedback of HR alone was no different from the control condition. All groups showed increased accuracy (P less than .05) by the third field trial [absolute error: T1 (18 bts/min) to T3 (9.6 bts/min); signed error: T1 (+14 bts/min) to T3 (+4 bts/min)]. Our results suggest feedback of HR combined with RPE during a GXT may reduce an overshoot in THR during the first of subsequent exercise sessions. Feedback of HR alone appeared sufficient to further reduce THR errors after a third exercise session in the field. The procedures used may have practical importance for sedentary, unfit, or diseased individuals where conservative HR prescriptions are desirable but electronic monitoring is not feasible or cost effective.

Adult↗
PubMed1982

Ratings of perceived exertion and heart rates during short-term cycle exercise and their use in a new cycling strength test.

Interest in tests of short-term maximal exercise capacity has increased during recent years. The purpose of this investigation was therefore to study how heart rates and ratings of perceived exertion increase during a work test when the subjects only have to exercise at each work load for 0.5 min and to study predictability of maximal performances. A differential test is obtained by using a series of submaximal ratings to estimate the exercise intensity that can be maintained for only 30 s. The validity of the estimated intensity was checked by having the subject exercise at that load. The test time obtained was then used to correct the estimated exercise intensity according to the general function describing the relation between exercise intensity and exercise time for maximal performances. In the validation the test performances were compared to results from (a) common submaximal ergometer test, and (b) a special test measuring dynamic muscular strength.

Adult↗
PubMed1995

[Complications of an idiopathic rhabdomyolysis (Meyer-Betz syndrome) after physical exertion].

A few hours after a 15 km march a 19-year-old man developed a fever of 40 degrees C, accompanied by hemoptysis, tarry stools and pain in the thigh. On physical examination there was tenderness and swelling over the shoulders, upper arms and thighs as well as petechiae, bruises, hepatomegaly, pain on percussion over the kidney region and signs of hypovolaemia. There was leukocytosis (18,800/microliters) and increased creatinase activity (3900 U/l, rising to 66,300 U/l after 24 h). The platelet count fell from 147,000 to 11,000/microliters, the fibrinogen level to 0.25 milligrams. On the second day serum creatinine was 4.1 mg/dl, urine volume 50 ml/24 h, urinary myoglobin concentration 120,000 micrograms/l. The Quick value dropped to under 3%, while liver enzymes and bilirubin concentration rose. The rhabdomyolysis caused acute respiratory failure, despite symptomatic treatment of the acute renal failure and consumption coagulopathy, but after 8 weeks of intensive treatment the patient was discharged without symptoms. No cause other than the preceding physical exertion was found for the rhabdomyolysis. Muscle biopsy revealed unspecific changes 4 1/2 months after discharge.

Acute Disease↗
PubMed1975

Exertional dyspnea and cough as preludes to acute attacks of bronchial asthma.

Although wheezing is believed to be a cardinal manifestation of asthma, some patients with this disorder may not present with wheezing, but rather with either exertional dyspnea or cough. In 14 such patients with dyspnea, there was peripheral airway dysfunction with markedly elevated residual volumes, frequency dependence of dynamic compliance and depressed flow rates in the middle-vital-capacity range, whereas specific conductance and one-second forced expiratory volumes were normal. Circumstantial evidence suggests that mucosal edema or mucous secretions may have been responsible. In seven patients with cough, studies revealed a more severe obstructive pattern that appeared to be the result of increased large-airway resistance, and the patients' response to isoproterenol indicated that contraction of bronchial smooth muscle may have been principally responsible. Thus, intermittent episodes of cough or breathlessness may represent variant aspects of asthmatic attacks.

Acute Disease↗
PubMed2003

Benign exertional headache.

We describe 4 patients with benign exertional headache presenting to the emergency department. Consideration of this uncommon cause of headache might facilitate an accurate diagnosis of those patients with headache caused by strenuous exercise.

Acetaminophen↗
PubMed2001

Postural discomfort and perceived exertion in standardized box-holding postures.

To help in the design or redesign of workplaces it would be helpful to know in advance the postural stress consequences of a wide range of body postures. This experiment evaluated 168 postures chosen to represent those in the Ovako Working-posture Analysing System (OWAS) using Rated Perceived Exertion (RPE) and Body Part Discomfort (BPD) measures. The postures comprised all combinations of three arm postures, four back postures, seven leg postures and two forces (weights of held boxes). Twelve male subjects held each posture for a fixed duration (20 s) before providing RPE and BPD ratings. Analysis of the ratings gave highly significant main effects, with the major driver being the object weight. As each factor was varied, the largest effect was on the body region corresponding to that factor. A simple main-effects-only additive model explained 91% of the variance of RPE means for the postures.

Adult↗
PubMed1996

Effects of asymmetric dynamic and isometric liftings on strength/force and rating of perceived exertion.

A laboratory study was undertaken to determine the postural and physical characteristics and subjective stress during dynamic lifting of a usual load (10 kg) compared with during isometric lifting. The authors also aimed to clarify the effects of asymmetric lifting on these parameters. The subjects were thirteen male college students. They were asked to lift a box weighing 10 kg. They performed sixteen different lifting tasks from the floor to a height of 71 cm, involving a combination of three independent factors: two lifting modes (isometric lifting and dynamic lifting), four lifting angles in relation to the sagittal plane (sagittal plane, right 45 degree, right 90 degree and left 90 degree planes) and two lifting postures (squat and stoop). For each lifting task, strengths or forces and ground reaction forces were measured. At the end of each task, the authors asked the subjects to rate their perceived exertion (RPE) during lifting at ten sites of the body. Angle factor had a significant effect on isometric strengths and dynamic peak forces. Isometric strengths during the maximum 3 s were highest in lifting in the right 45 degree plane, followed by that in the sagittal plane, while those in the right 90 degree and left 90 degree planes were the lowest. However, peak forces in dynamic lifting were the highest in the lifting in the sagittal plane, followed by that in the right 45 degree plane, while those in the right 90 degree and left 90 degree planes were the lowest. Postural factor had a significant effect on height at peak force, which is higher in squat lifting than in stoop lifting. RPEs for the left arm, the backs and the right whole body in isometric lifting were significantly higher than in dynamic lifting of 10 kg. There were remarkably high RPEs for the ipsilateral thigh to the box in right 90 degree and left 90 degree planes during both isometric and dynamic liftings. Locations of the resultant force consisting of three component forces on the force plate were closer to the foot on the same side as the box in asymmetric lifting. Thus, some similarities and differences were found between isometric lifting and dynamic liftings regarding the indexes of strength used in this experiment. The authors consider that the subjects used the foot nearer to the box as a fulcrum during asymmetric lifting. Dynamic measurement using the 10 kg weight is less stressful than the conventional isometric measurement. It was possible to obtain the height data at peak force and time-based changes in the force and the box location during lifting only through dynamic lifting measurement. The results provide new knowledge about the biomechanical features of dynamic lifting tasks.

Adolescent↗
PubMed1998

Ratings of perceived exertion (RPE) during cycling exercises at constant power output.

The purpose of the present investigation was to study the overall rating of perceived exertion (RPEov) according to the 6-20 scale proposed by Borg (1970) and muscular RPE (RPEmu) in exercises at constant load. The relationship between RPE and heart rate for three different loads was studied during exhausting exercises in 10 participants. Whether the drift of RPE during a 20 min exercise at constant load could be an index of the endurance time during long-lasting exercises at constant load was also investigated. At 1-week intervals, the participants performed cycling exercises up to exhaustion at 60, 73, and 86% maximal aerobic power (MAP) measured during an incremental test. Heart rate, RPEov, RPEmu and exhaustion time (tlim) were measured. The upward shift of the HRmax-RPE regressions was significant between 86, 73 and 60% MAP (p < 0.001) for RPEov and RPEmu. This result suggests that the equation HR = 10 x RPE proposed by Borg (1973) for incremental exercise is not valid for long-lasting exercise at constant load until exhaustion because the heart rate corresponding to a given RPE depends on load and time. Mean RPE increased linearly with time up to exhaustion. Unexpectedly, the relationships between RPEmu or RPEov and percentage of exhaustion time were similar for exercises at 60 and 73% MAP although the exhaustion times were very different (79.40 +/- 30.64 min versus 36.19 +/- 15.99 min, respectively) (p < 0.001). Consequently, it is likely that RPE was a subjective estimation of the hardness of exercise rather than the intensity of exercise. The RPE pattern at the beginning of long-lasting exercises at constant load (60 and 73% MAP) cannot be considered as a sensitive predictor of the point of self-imposed exhaustion for individuals. Indeed, the errors in the estimation of exhaustion time from extrapolation of RPE at the beginning of exercise were very large. Moreover, at 60% MAP, a steady-state in RPE was observed during 20 min in five subjects whose tlim were not longer than tlim of the other subjects. In addition, the data of the present study indicate that RPEmu could be more useful than RPEov in cycling.

Adult↗
PubMed1998

Ratings of perceived exertion (RPE) as an index of aerobic endurance during local and general exercises.

The main purpose of this study was to assess the correlations of RPE with indicators of endurance (critical power), exhaustion time and the electromyographic activity of a relevant muscle during general and local exercises. Eight healthy subjects participated in the study. During the first session, Maximal Aerobic Power (MAP) was measured by means of an incremental cycling exercise on a Monark ergometer. At 1-week intervals the participants performed a general or local exhausting exercise, which consisted of a cycle exercise (60, 73, 86 or 100% MAP) and a knee extension exercise (lifting a load between 17.5 and 32.5 kg every 3 s), respectively. The critical powers corresponding to cycling (CPcycling) and knee extension (CPknee) were calculated from the slope of the linear relationship between exhaustion time (tlim) and work. Rate of perceived exertion, concerning the whole body (overall RPE [RPEov]), RPE concerning the exercising muscles (muscular RPE [RPEmu]) and exhaustion time were measured. During the last session, the integrated electromyogram of the right Vastus Lateralis (iEMG s-1) was measured during short (20 s) cycling and knee extension non-exhausting exercises, with the same electrode location, at the different power outputs used during the exhausting exercises. The relationships between RPEmu at the fifth minute and log tlim and between iEMG% (percentage of the iEMG s-1 corresponding to 100% MAP during cycling) and log tlim were similar for the cycling and knee extension exercises. The mean values of RPEmu at the fifth minute of exercise calculated for CPcycling and CPknee were almost equal (12.3 +/- 1.7 versus 12.2 +/- 0.9). Similarly, the mean values of iEMG% corresponding to CPcycling and CPknee were equal (78.44 versus 79.02%). These results suggest that RPEmu is related to aerobic endurance and that the possibility of sustaining a high percentage of maximal aerobic power during a general exercise is mainly related to local muscular factors.

Adult↗
PubMed1999

Relating heart rate and rate of perceived exertion in two simulated occupational tasks.

The purpose of this study was to examine the relationship between ratings of perceived exertion (RPE) and activity intensity, as determined by heart rate. Fifteen participants completed a standardized treadmill protocol in order to establish a heart rate--RPE calibration profile. These participants then completed two simulated occupational tasks--box carrying and sweeping. During the simulated tasks, heart rates and RPE values were recorded every minute from the third to tenth minute and then averaged over that period. There was a moderate, but statistically significant, correlation between monitored heart rate and heart rate predicted from RPE scores for both the box carrying (r = 0.70) and sweeping (r = 0.73) simulations. Direct prediction of task heart rate from RPE reported during the task was not as strongly correlated for the box carry (r = 0.11), as it was for the sweeping activity (r = 0.68). Results from this study suggested that heart rate monitoring alone does not account for enough of the variability resulting from both local and central mediation of RPE.

Activities of Daily Living↗
PubMed1988

Use of submaximal measures of perceived exertion during bicycle ergometer exercise as predictors of maximal work capacity.

Submaximal measures of perceived exertion, aches and pain in the legs, heart rate and blood lactate were made in a bicycle ergometer test. Their predictability of maximal work capacity, measured as Wmax, was studied. Twenty-eight males in good physical condition served as subjects and cycled in a graded exercise test up to a voluntary maximum. The reliability coefficients for both the psychophysical variables--measured on Borg's CR-10 scale--and heart rate were high. Provided that a proposed preliminary division of the subjects into subgroups with regard to their physical fitness was undertaken, the regression analyses showed that the psychophysical variables were the best predictors of Wmax. Linear and curvilinear predictions, graphic or calculated, had lower explained variance but also showed that the psychophysical variables are good predictors of maximal work capacity.

Adult↗
PubMed1989

Effect of time of day on perceived exertion at work rates above and below the ventilatory threshold.

The effect of time of day on ratings of perceived exertion (RPE) at various intensities of cycling exercise, both below and above the ventilatory threshold, was studied in 32 subjects, 18 to 35 years of age. The ventilatory threshold occurred at the same (p greater than .05) mean (+/- SD) work rate in the morning (110.6 +/- 27.0 watts) and in the afternoon (111.9 +/- 23.9 watts) and was perceived as equally strenuous (p greater than .05) in the morning (RPE = 13.8 +/- 2.4) and in the afternoon (RPE = 13.6 +/- 2.8). At intensities below the ventilatory threshold, RPE was the same (p greater than .05) in the morning and in the afternoon; above the ventilatory threshold, RPE was lower (p less than .05) in the morning. We conclude that, during incremental submaximal cycling exercise above the ventilatory threshold, a particular work rate is perceived as less strenuous in the morning than in the afternoon. About 20% of this difference in RPE is explained by lower ventilatory demands in the morning.

Adolescent↗
PubMed2005

Reliability of heart rate responses at given ratings of perceived exertion in cycling and walking.

Eleven healthy men (M age = 27 years, SD = 4) completed three cycling and three walking trials in an alternating order. During each trial, participants were allowed, within 3 min, to adjust the work rate to correspond to given rating of perceived exertion (RPE) values according to the following order: RPE 11, 13, and 15. For cycling as well as walking, at each RPE there were no significant differences between mean heart rate responses across the three trials (p > .05). Mode-specific estimates for heart rate intraclass correlation coefficient and coefficient of variation ranged between .80 and .91, and 5.6% and 8.3%, respectively. This study provides absolute reliability estimates for heart rate responses when using RPE in a production format and suggests there may be RPE- (and mode) specific practice requirements for achieving a reliable heart rate response at a given RPE.

Adult↗
PubMed2000

Visual analogue scale for the perceived influence of exertion and movements/positions on low back problems in surveys of adolescents.

UNLABELLED: The test-retest reproducibility of visual analogue scales for the perceived influence of exertion and movements/positions on low back problems in adolescents was investigated. The study was performed on 61 adolescents with low back problems. Item completion, median score, interquartile range and weighted kappa were calculated. Results showed that visual analogue scales produce repeatable information for all items tested (weighted kappa: 0.59-0.83), except for the influence of pulling materials on back problems (0.45). CONCLUSION: The results of this study suggest that adolescents, aged 16-18 y, can reproduce their visual analogue scores.

Adolescent↗