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PubMed2006

Case report of exertional rhabdomyolysis in a 12-year-old boy.

INTRODUCTION: Exertional rhabdomyolysis has been well characterized, and many case reports exist. No cases of exertional rhabdomyolysis in young healthy children (preteen) have been published. CASE SUMMARY: Reviewed were the medical records of a 12-yr-old boy who participated in an indoor physical education class where excessive (>250) repetitive squat jumps were performed as punishment for talking in class. The boy, who reported intense muscle soreness in the thighs and dark urine 2 d postexercise, was brought to the emergency room by his parent. His serum creatine kinase (CK) was 92,115 U.L(-1) and urinalysis indicated the presence of blood and protein. He was transferred to another hospital that evening, admitted, and treated for 7 d. His serum CK rose to 244,006 U.L(-1) at 4 d postexercise. CONCLUSION: Although exertional rhabdomyolysis is rare in young children, it can occur when excessive exercise is spurred on by an adult.

Child↗
PubMed2006

Validity of PCERT and OMNI walk/run ratings of perceived exertion.

PURPOSE: This study was conducted to test the validity of the Pictorial Children's Effort Rating Table (PCERT) and OMNI walk/run scales. METHODS: Children (26 boys age 11.2 yr +/- 1.6 and 25 girls age 11.1 yr +/- 1.4) performed a five-stage incremental exertion treadmill test. The undifferentiated perceived exertion from the PCERT and OMNI scales was assessed for construct validity using Pearson correlations with VO(2) and heart rate as criteria and concurrent validity by correlating PCERT and OMNI scores. RESULTS: Increases in PCERT and OMNI scale scores were correlated with increases in VO(2) (r = 0.90 and 0.92) and heart rate (r = 0.89 and 0.92). No difference was found in slope of the PCERT and OMNI scores when regressed against heart rate or VO(2) and the slopes were invariant across sexes. To test concurrent validity of the PCERT and OMNI scales, subject scores at each stage were converted to a percentage of the maximal scale. No effect of sex was noted on perceived exertion (P = 0.32), and the percentage of the maximal PCERT and OMNI scales was almost identical at each stage (P = 0.73). CONCLUSIONS: Validity of both the PCERT and OMNI scales was established for submaximal exercise. PCERT and OMNI scores are not interchangeable because they have different scales, but at a given exercise intensity youth assign similar percentages of the maximal scores.

Child↗
PubMed1992

Isolated reduction in single-breath diffusing capacity in the evaluation of exertional dyspnea.

UNLABELLED: STUDY SETTINGS AND INTERVENTIONS: Sixty individuals complaining of dyspnea on exertion, but with normal spirometry and lung volumes and normal chest roentgenograms were reviewed for this study. These individuals were selected from a large group of outpatients (552 individuals over a seven-year period) who were referred to our laboratory for exercise testing to determine the cause of their exertional dyspnea. They were grouped according to the single-breath diffusing capacity, with those less than 70 percent of predicted in the low DCO group (group 1) and those greater than 70 percent of predicted in the normal DCO group (group 2). Both study groups underwent an incremental exercise test. RESULTS: Twenty-three individuals had a DCO less than 70 percent of predicted. During exercise, seven of these (30 percent) had an abnormal PaO2 and five had an abnormal P(A-a)O2. Thirty-seven people had a normal DCO. Thirty-six of these (97 percent) had a normal PaO2 and P(A-a)O2 during exercise. Overall, eight individuals had an abnormal PaO2 or P(A-a)O2 during exercise; seven of these had an abnormally low DCO at rest. CONCLUSIONS: Based on this selected group of a subpopulation, we conclude that the DCO is an important determinant of the diagnostic approach to a patient with dyspnea who is otherwise normal. If all pulmonary functions, including DCO are normal, an exercise study will fail to reveal abnormal PaO2 or P(A-a)O2 in 97 percent of the cases. However, a low DCO has a poor predictive value with respect to abnormal gas exchange during exercise. Therefore, when investigating exertional dyspnea, based on this selected subpopulation, if the spirometry, lung volumes, and DCO are normal, one may forego additional invasive gas exchange evaluation. However, an abnormal DCO warrants further physiologic testing.

Blood Gas Analysis↗
PubMed1975

Exertional hemoglobinuria.

A 16 years old boy had a typical exertional hemoglobinuria after walking with his new leather shoes on. The attacks of hemoglobinuria were associated with the appearance of an unstable hemoglobin in red cells. A slightly decreased fragility curve by 24 hr incubated red cells, the increase of autohemolysis and the appearance of heat labile hemoglobin were observed after exertion. These findings support that exertional hemoglobinuria may be regarded as a transitory erythropathia.

Adolescent↗
PubMed1991

Effects of blood glucose concentration on ratings of perceived exertion during prolonged low-intensity physical exercise.

The purpose of this investigation was to determine the relationship between blood glucose concentration and perceived exertion during prolonged low-intensity exercise. After a 12-h overnight fast, seven young healthy males began bicycle exercise from 0800 h at 50% Vo2max. One hour after initiation of the exercise, 20% glucose was infused by means of an infusion pump, to maintain blood glucose concentration at a level of approximately 6.5 mM for 20 min. This was followed by 20 min of sham infusion (no glucose). This 40-min cycle was repeated until 220 min of exercise. During the first 120 min of exercise, the ratings of perceived exertion (RPE) increased gradually without any effects of the glucose infusion. Thereafter, RPE tended to decrease during glucose infusion, and finally showed a significant decrease from 180 (17 +/- 2) to 190 (16 +/- 2) min. This result showed that an increase in blood glucose concentration has a significant effect on perceived exertion, even if exercise time is prolonged. The different responses of RPE during the two phases of the exercise may be explained by the difference of glycogen concentration in muscle, because glucose infusion had no effect on RPE when muscle glycogen content was presumed to be at normal level, and was effective when glycogen in the exercising muscles was presumed to be depleted.

Adult↗
PubMed2005

Influence of acetaminophen consumption on perceived exertion at the lactate concentration threshold.

The purpose of this investigation was to study effects of acetaminophen consumption on ratings of perceived exertion and estimated time limit responses at the lactate threshold. 98 young regional to national level athletes performed a graded exhausting exercise on an outdoor running track to estimate their maximal aerobic velocity and the velocity associated with their lactate concentration threshold. Urine (30 mL) was collected during this test and analysed for numerous substances. During urinary screening for doping substances, 9 acetaminophen consumers (9.2%) among the 98 included athletes were detected. These acetaminophen consumers have significantly lower perceived exertion at velocity corresponding to the lactate concentration threshold than nonconsumers (11.9 +/- 2.1 vs 13.6 +/- 2.1, respectively) although they were at the same relative exercise intensity. This result shows that acetaminophen consumption may have mediated the perceived exertion response at the lactate concentration threshold. This may then suggest that the pain induced by training load could be a factor in use of self-prescribed pain relievers. Such consumption must be taken into account by medical staff, trainers, or educators who have to give information on the use and adverse effects of this substance and to propose palliative methods to their athletes.

Acetaminophen↗
PubMed2006

Factors associated with perceived exertion and estimated time limit at lactate threshold.

The purpose was to identify the most predictive parameters for perceived exertion and estimated time limit responses at the velocity corresponding to the lactate concentration threshold. The former scale concerns the subject's current status (how hard he feels the exercise currently is) whereas the latter scale deals with a subjective prediction of how long the current exercise level can be maintained. Multiple regression equations were developed among physiological, psychological, nutritional, and individual parameters (subjects' characteristics and performances) as independent variables, and perceived exertion or estimated time limit as dependent variables. Independent variables were collected before or during an incremental running field test. 94 regional to national level athletes (47 endurance-trained runners, 11 sprinters, and 36 handball players) participated. Multiple stepwise regression showed that Rating of Perceived Exertion and Estimated Time Limit at the lactate threshold were mainly mediated by factors relative to the performance expressed in percentage of the maximal aerobic velocity. Secondary factors which contribute significantly as perceptual predictors were related to various classes of factors except for psychological factors.

Adaptation, Psychological↗
PubMed1975

Differentiated ratings of perceived exertion during physical conditioning of older individuals using leg-weight loading.

Use of leg weights for physical conditioning was evaluated in 8 middle-aged male Ss; four Ss of similar age served as a control group. Pre- and post-training evaluation consisted of heart rate and oxygen uptake responses to five submaximal work loads which involved either level walking or cycling. Differentiated ratings of perceived exertion elicited for each work load were: a local muscular rating; a central or cardio-pulmonary rating; and an over-all or general rating. Submaximal heart rate decreased 6 to 9 beats/min. from pretraining values for all work load after training. The differentiated ratings for training generally reflected a reduced strain on the cardiovascular system and also improved functioning of the working muscles with training. However, when one set of sensations dominated the exertional perception the others appear to have been perceptually de-emphasized. Local muscular factors seemed to dominate the exertional perception for cycling, but central factors appeared to play a more important role for treadmill walking, at least within the range of velocities investigated.

Adult↗
PubMed1977

Perceived exertion and stimulus intensity modulation.

Perceptual augmentation and reduction were considered contrasting styles of Stimulus Intensity Modulation. Differences in perceived exertion between augmenters and reducers were determined for three cycle ergometer work loads. Subjects were 20 males having similar physiological characteristics. Stimulus Intensity Modulation was determined by kinesthetic figural aftereffect. Augmenters rated their perceptions of physical exertion to be more intense than reducers at 450, 750 and 1050 kpm/min. Differences in physiological responses between augmenters and reducers were not significant at the three work loads. Style of Stimulus Intensity Modulation appeared differentially to influence perceived exertion at the work levels studied.

Blood Chemical Analysis↗
PubMed1978

Perceived exertion and the field-independence--dependence dimension.

Perceived exertion responses were compared between field-independent and field-dependent perceivers at three cycle-ergometer pedalling rates. 50 male subjects were classified according to mode of field approach on the basis of their performance on an embedded-figures test. Power output was held constant at 840 kpm/min., while pedalling rate was randomly set at 40, 60, or 80 rpm. Significant differences between the field-independent and -dependent groups were not found at the three pedalling rates for any of the physiological variables or for over-all, legs and chest ratings of perceived exertion. The extent of differentiated psychological functioning did not account for individual differences in perceptual reactance during muscular exertion.

Adult↗
PubMed1991

Effects of speed and accuracy of exertion of force on the relationship between force output and fractionated reaction time.

The present study was designed to investigate the effect of speed and accuracy of force exertion on the relationship between force output and fractionated reaction time. Subjects exerted their force (10% or 40% of maximum isometric contraction) on "accurate" and "fast" tasks as rapidly as possible at the light signal. On the "fast" task, premotor time for the 40% target was lengthened in comparison with that for the 10% target, and motor time was shortened with an increase of force output. On the "accurate" task, on the other hand, premotor time was independent of magnitude of force, and no relation between motor time and force output was found. These findings show that the relationship between force output and fractionated reaction time may be affected by the effort to exert force accurately.

Adult↗
PubMed1992

Metabolic demands and perceived exertion during cardiopulmonary resuscitation.

Emergency situations often require continuous execution of one-person cardiopulmonary resuscitation (CPR) for periods of time in excess of 30 minutes. The limited research which has examined the demands of the procedure has focused on central physiological measures, despite (1) the use of a subjective end-point for termination of CPR (i.e., exhaustion) as stated in professional guidelines, and (2) significant peripheral involvement in the form of muscular exertion, a phenomenon more closely linked to Ratings of Perceived Exertion (RPE) than to central factors. To examine subjective responses to performing CPR, 8 healthy, sedentary subjects [M age = 20.8 (yr) +/- .4; weight (kg) 82.6 +/- 7.1; height (cm) 183.7 +/- 2.8] reported differentiated Ratings of Perceived Exertion (RPE) following 10 minutes of one-person CPR testing. While metabolic data observed during CPR support previous research suggesting that the energy demands of performing CPR are relatively low, both peripheral and over-all RPE were significantly higher than central (respiratory-metabolic) RPE. Over-all RPE was also significantly greater than peripheral RPE. The data suggest research investigating CPR demands based on central measures may underestimate actual as well as perceived demands of performing the procedure. In addition, the considerable interindividual variability in the relative energy cost (% VO2 max) of performing one-person CPR suggests that the fitness level of the individual may be a limiting factor in the ability to perform CPR for extended periods of time.

Adult↗
PubMed1993

Physical exertion and immediate mental performance of sixth-grade children.

The intent of this investigation was to examine the potential influence of varying durations of physical exertion at different times of the day on immediate mathematical performance by 120 sixth-grade boys and girls. Subjects were assigned to two control and two treatment groups (Solomon Four-group Design), with treated subjects administered physical exertion (paced walking at controlled moderate intensity) for durations of 20, 30, and 40 min. at three different times of the school day [8:30 a.m., 11:50 a.m. (before lunch), 2:20 p.m.] over 3 weeks. After each exertion session, subjects were immediately administered a 90-sec. mathematical computation test. Analysis indicated no significant differences in mathematical performance at any duration in the morning, but scores were significantly higher at 11:50 a.m. and 2:20 p.m. at 30- and 40-min. durations in comparison to the 20-min. duration. There were no differences by gender of subject.

Arousal↗
PubMed1996

Effect of carbohydrate substrate availability on ratings of perceived exertion during prolonged exercise of moderate intensity.

This investigation examined the effect of carbohydrate substrate availability on ratings of perceived exertion (RPE) during cycling at moderate intensity to exhaustion and the relation between submaximal endurance performance and RPE obtained following 2 hr. of cycling at moderate intensity. Seven male cyclists performed two exercise trials at power output corresponding to 70% of their peak oxygen uptake until exhaustion. Subjects ingested either a 6% glucose/sucrose solution at the rate of 0.6 g.kg-1 (Body Weight).hr.-1 or an equal volume of artificially flavored placebo every 20 min. throughout the exercise trials. RPE for the legs, chest, and over-all body, and oxygen consumption, expired ventilation, carbohydrate oxidation rate, and blood concentrations of glucose, glycerol, and lactate were measured every 20 min. throughout exercise and at exercise termination. Statistical analysis of these dependent variables indicates that (1) an exercise-induced decrease in blood-borne carbohydrate substrate intensifies leg and over-all perceptions of exertion during the later stages of prolonged cycling at 70% VO2peak. (2) Factors other than availability of blood-borne carbohydrate substrate may influence perceptual intensity at exhaustion. (3) Ratings of perceived exertion for the legs and over-all body obtained after 2 hr. of cycling at moderate intensity may be useful in predicting submaximal endurance performance.

Attitude to Health↗
PubMed1996

Effect of viewing the RPE scale on the ability to make ratings of perceived exertion.

7 subjects exercised while viewing and not viewing the Rating of Perceived Exertion scale during exercise to assess whether ratings of perceived exertion are influenced by viewing the scale itself. Analysis suggested that monitoring moderate to high intensity exercise without viewing the RPE scale may result in an underestimation of exertion.

Adult↗
PubMed1998

Effects of an external nasal dilator strip on differentiated ratings of perceived exertion.

17 college-age subjects performed two 20-min. runs at 65% of maximal oxygen consumption. Randomized trials were conducted with an external nasal dilator strip or without. Subjects were polled every 5 min. for over-all rating of perceived exertion, central rating of perceived exertion, and local rating of perceived exertion. The use of an external nasal dilator strip did not significantly lower any of the three

Analysis of Variance↗
PubMed2004

Validity and reliability of a Cantonese-translated rating of perceived exertion scale among Hong Kong adults.

This study assessed the validity and reliability of the Cantonese-translated version of the Borg 6-20 Rating of Perceived Exertion (RPE) scale during continuous incremental cycle ergometry by Hong Kong adults. A total of 54 participants (25 males and 29 females), ages 22.2 +/- 4.7 yr., volunteered to participate. They performed two trials of identical continuous incremental cycling exercise 1 wk. apart for the reliability test. The objective measures of exercise intensity (heart rate, power output, and oxygen consumption) and the subjective measure of effort (RPE) were obtained during the incremental exercise. Significant (p < .01) Pearson correlations were found when RPE values were correlated with heart rate (rs > or = .73), power output (rs > or = .69), and oxygen consumption (rs > or = .68). The overall test-retest intraclass correlation (R = .92) indicated that the scale was reliable. In conclusion, this Cantonese scale for rating of perceived exertion appears to be a valid and reliable psychophysiological tool to measure perceptions of exertion during controlled cycle ergometer exercise by Hong Kong adults.

Adult↗
PubMed2004

Relationships among coordinated exertion of force and performance on pegboard and pursuit rotor tests using upper limbs and fingers.

This study assessed the relationships between coordinated exertion of force and performance on pegboard and pursuit-rotor tests. University students (30 men and 30 women; M=20.4 yr., SD=1.1) matched their submaximal grip strength to changing demand values displayed as either a bar chart or a waveform appearing on the display of a personal computer and performed pursuit-rotor and pegboard tests. Sex differences were not significant. Correlations with maximal grip strength were minimal. Performance on coordinated exertion of force test was moderately correlated (men: r=-.42, women: r=-.70) with performance on the pursuit-rotor test for both sexes, but not with scores on the pegboard test. Scores on the coordinated exertion of force test and these two tests using upper limbs and fingers have little relation to maximal grip strength, and the correlations among them are similar for both sexes.

Adult↗