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Differentiated perceptions of exertion and energy cost of young women while carrying loads.

Differentiated local ratings of perceived exertion from the legs and central ratings from the chest, and oxygen consumption, were determined during load carriage in seven young women. Subjects walked for 6 min at 3.22, 4.83, 6.44, or 8.05 km X h-1 carrying (1) no load, (2) a load equal to 7.5% of body weight (mean: 4.66 kg) or (3) a load equal to 15% of body weight (mean: 9.32 kg). Thus, each subject underwent 12 separate tests. The external loads were in the form of lead pellets carried in a plastic scuba belt worn around the waist. A differentiation threshold was found at 6.44 km X h-1 for the 0% and 7.5% loads and at 4.83 km X h-1 for the 15% load. At speeds below the threshold, the perception of exertion was similar in the legs, chest and overall. At higher speeds, exertion was perceived to be more intense in the legs than overall and less intense in the chest than overall, suggesting that the local legs signal was the dominant factor in shaping the overall sensation of exertion. The oxygen uptake was greater for the 15% load than for either the 0% or 7.5% loads, but was similar for the 0% and 7.5% loads. Findings suggested a critical weight limit for external loads that could be transported without increasing the metabolic cost beyond that required to move the body weight alone. This limit fell between 7.5% and 15% of the body weight. When oxygen uptake was expressed per kg of total weight transported, there was no loss of metabolic efficiency while carrying loads up to 15% of the body weight.

Adult↗

Effects of order of presentation of exercise intensities and of sauna baths on perceived exertion during treadmill running.

Thirteen male subjects performed a running test on the treadmill consisting of four standard exercise intensities [65%, 75%, 85%, 95% maximal O2 uptake (VO2 max)] presented in ascending, descending or random order. At the end of each exercise intensity, O2 consumption, heart rate (fc), venous blood lactate concentration [( Ia]b) and perceived exertion were assessed. This last variable was determined according to the Borg nonlinear CR-20 scale. The same variables were also determined during exercise at a standard intensity (65% or 95% VO2 max) performed before and after a Finnish sauna bath. Ratings of perceived exertion showed a good test-retest reliability (r = 0.77); they were the same when the exercise intensity was expressed in relative (%VO2 max) or absolute (speed) terms, and were independent of the order of presentation of the exercise. The latter had no effect on fc either but it did, however, influence [Ia]b, which was significantly higher in the descending, as compared to the ascending or random modes of presentation. The sauna bath increased fc at a given exercise intensity, but left perceived exertion and [Ia]b unchanged. It was concluded that at least under the present experimental conditions, fc and venous [Ia]b do not play a major role as determinants of perceived exertion.

Adult↗

Relationship between perceived exertion and mean power frequency of the EMG signal from the upper trapezius muscle during isometric shoulder elevation.

The aim of the study was to investigate the relationship between a fatigue-induced increase of perceived exertion in the neck with a decrease of mean power frequency (MPF) in the surface electromyography (sEMG) signal during repeated shoulder elevation endurance tasks. About Thirty-two healthy women (age range 20-62) performed two maximum 6-min shoulder elevation endurance tasks at 30% of their maximal voluntary contraction (MVC) level, separated by a rest of 6 min. During these exercises, perceived exertion was estimated using the Borg scale (range 0-10), whereas the MPF of the sEMG signal from the upper trapezius was simultaneously detected. Linear regression analysis was applied over time for each trial and subject for both MPF and Borg scale rating values. The MPF was normalized by the intercept of the linear regression analysis. The resulting slopes of normalized mean power frequency (nMPF) and Borg scale rating were correlated with each other by linear regression for both trials. In order to investigate the individual behavior of fatigue effects between trials, Delta (trial 2-trial 1) slopes of nMPF and Borg scale ratings were calculated for each subject. These slopes of nMPF and Borg scale ratings were correlated with each other as well by linear regression. The increase of Borg scale ratings, as well as the decrease of nMPF, were significantly higher in trial 2 than trial 1 (P<0.01). The results show a linear correlation between slopes of nMPF and Borg scale ratings for both trials 1 and 2 (r=0.76, P<0.01). Trial-to-trial slopes (Delta (trial 2-trial 1)) of nMPF and Borg scale rating, were also significantly correlated (r=0.68, P<0.05). Thus, the individually sensed increase of perceived exertion in the neck during trial 2 was accompanied by a simultaneously higher detected decrease of nMPF. These findings indicate a close relationship between subjective perception of exertion in the neck and objectively assessed muscle fatigue of the upper trapezius.

Adult↗

Exertion dependent alternations in force fluctuation and limb acceleration during sustained fatiguing contraction.

The study was conducted to contrast exertion-dependent changes in electromyography (EMG), force fluctuation (FF), and limb acceleration (LA) during isometric contraction to attain a versatile picture of muscle fatigue. Fifteen volunteers performed sustained index abduction at 25 and 75% maximal voluntary contractions (MVC) until failure at the tasks; meanwhile, changes in temporal/spectral features of force, muscle activity of the first dorsal interosseous (FDI), and acceleration of the index and hand were monitored. The results showed a manifest increase in all recorded signals for the 25% MVC paradigm, especially for LA, which demonstrated the largest increment in amplitude. In addition to progressive enhancement of the mechanical coupling of the metacarpophalangeal (MCP) joint, the 25% MVC paradigm added to EMG-FF and EMG-LA coherences (CohEMG-FF and CohEMG-LA) at 8-12 Hz and the shift of the spectral peak of the LA to higher frequencies. In contrast, the 75% MVC paradigm did not modulate significantly the spectral peak of LA. Also, CohEMG-FF, CohEMG-LA at 8-12 Hz, and the mechanical coupling of the MCP joint, were conversely undermined consequent to the high exertion paradigm. The present study suggests that LA was most susceptible to muscle fatigue following sustained contraction at a lower exertion level, and diverging alternations among various physiological signals ascribed to exertion-dependent contributions of central and peripheral origins to muscle fatigue.

Acceleration↗

Effects of antidepressant administration on physical performance and perceived exertion in athletes: systematic review and meta-analysis.

INTRODUCTION: Antidepressants are commonly prescribed in athletes with depressive disorders, yet their potential effects on physical performance and perceived exertion remain unclear, and existing evidence is limited and inconsistent. AIM: This systematic review and meta-analysis aimed to evaluate the effects of antidepressant use on objective physical performance and perceived exertion in athletes. METHOD: A systematic literature search was conducted in PubMed, the Cochrane Library, Web of Science, and SPORTDiscus through March 2025. Eligible studies were randomised controlled trials (RCTs) published in English that enrolled elite, competitive, or recreational athletes; compared antidepressant administration with placebo or no treatment; and reported at least one objective or subjective performance-related outcome. Meta-analyses were performed using random-effects models, and pooled mean differences with 95% confidence intervals (CI) were calculated. This systematic review and meta-analysis was registered in PROSPERO (CRD420251123740). RESULTS: Ten crossover RCTs involving 99 male athletes were included. Interventions included a norepinephrine reuptake inhibitor (reboxetine), a norepinephrine-dopamine reuptake inhibitor (bupropion), and selective serotonin reuptake inhibitors (fluoxetine or paroxetine). Acute antidepressant administration was associated with a small increase in rating of perceived exertion (RPE; mean difference 0.52 points on the Borg 6-20 scale, 95% CI 0.01-1.04; p&#x2009;<&#x2009;0.05). No significant overall effects were observed for time-trial performance, mean power output, heart rate or blood lactate. However, subgroup analyses showed that reboxetine significantly impaired time-trial performance (mean difference 3.62&#xa0;min, 95% CI 0.18-7.06; p&#x2009;<&#x2009;0.05) and reduced mean power output (mean difference&#x2009;-&#x2009;19.97 W, 95% CI&#x2009;-&#x2009;36.87 to&#x2009;-&#x2009;3.06; p&#x2009;<&#x2009;0.05). CONCLUSION: Short-term antidepressant administration in athletes was associated with a small increase in perceived exertion, without consistent impairment in objective physical performance. As the current evidence derives exclusively from male athletes and acute exposure, further research should clarify its relevance to female athletes and to longer-term antidepressant treatment in athletes with depressive disorders.

Humans↗

Left ventricular exercise echocardiographic abnormalities in apparently healthy men with exertional hypotension.

Of a total of 1,435 healthy untrained asymptomatic individuals referred for a routine periodic checkup, 23 subjects with exertional hypotension on upright bicycle stress testing were identified. All were male. This study assesses by means of echocardiography the responses to exercise of left ventricular (LV) volumes, ejection fraction and segmental LV contractility in these subjects. Exertional hypotension was defined as a decrease in systolic blood pressure to below the resting value at the end of stress test. Supine systolic blood pressure after exercise was significantly greater in the control group than in the study group (179 vs 121 mm Hg, respectively; p less than 0.001); there was no significant intra- or intergroup difference in the resting values. In the study group end-systolic volume was 37 ml at rest and 35 ml after exercise; ejection fraction varied from 65% at rest to 63% after exercise. The sex- and age-matched control group with a normal systolic blood pressure response to exercise showed a shift from 35 to 23 ml and 65 to 77%, respectively (p less than 0.01 and 0.001). Ejection fraction correlated well with radionuclide angiography values. Exertional hypotension was noted after both upright and supine exercise. The pattern of regional wall motion remained unchanged or was hypokinetic in 87% of the subjects; only 13% presented the normally expected hyperkinesia after exercise. This study demonstrates that exertional hypotension is accompanied by an abnormal LV performance.

Adult↗

Regional thallium-201 washout and myocardial hypertrophy in hypertrophic cardiomyopathy and its relation to exertional chest pain.

The mechanism of exertional chest pain in hypertrophic cardiomyopathy is uncertain, but may relate to myocardial ischemia. To study the mechanism of exertional chest pain in hypertrophic cardiomyopathy, dipyridamole-stress thallium-201 single-photon emission computed tomography was performed in 82 consecutive patients, and the 3-hour washout of thallium in relation to the tomographic image, regional wall thickness on echocardiography, and other clinical findings was analyzed. There was a weak inverse correlation of regional washout and wall thickness in 298 analyzed quadrant areas (r = -0.29; p = 0.0001). Twenty-five patients (31%) had history of exertional chest pain, and showed a significantly lower total washout and greater maximal left ventricular wall thickness than did those without chest pain (32 +/- 10% vs 37 +/- 9% [p = 0.03], and 27 +/- 7 vs 23 +/- 7 mm [p = 0.03], respectively). Even in mildly and nonhypertrophied areas, patients with chest pain had a significantly lower regional washout than did those without pain (33 +/- 10% vs 38 +/- 9%; p = 0.02), despite similar left ventricular wall thickness (12 +/- 2 vs 11 +/- 3 mm; p = NS). Reduced washout was strongly associated with exertional chest pain and was observed in myocardial regions that had normal as well as increased thickness, which indicates that this abnormality of thallium kinetics is a function of the disease process and not the magnitude of left ventricular hypertrophy.

Adolescent↗

Concordance between VDU-users' ratings of comfort and perceived exertion with experts' observations of workplace layout and working postures.

The aim of the present study was to evaluate the concordance (agreement) between VDU-users' ratings of comfort and ergonomists' observations of workplace layout, and the concordance between VDU-users' ratings of perceived exertion and ergonomists' observations of working postures during VDU-work. The study population consisted of 853 symptom free subjects. Data on perceived comfort in different dimensions and data regarding perceived exertion in different body locations were collected by means of a questionnaire. Data concerning workplace layout and working postures were collected with an observation protocol, by an ergonomist. Concordance between ratings of comfort and observations of workplace layout was reasonably good for the chair and the keyboard (0.60, 0.58) and good regarding the screen and the input device (0.72, 0.61). Concordance between ratings of perceived exertion and observations of working postures indicated good agreement (0.63-0.77) for all measured body locations (neck, shoulder, wrist and trunk). In conclusion ratings of comfort and perceived exertion could be used as cost-efficient and user-friendly methods for practitioners to identify high exposure to poor workplace layout and poor working postures.

Adult↗

Maximal dynamic grip force and wrist torque: the effects of gender, exertion direction, angular velocity, and wrist angle.

The objective of this study was to examine the effects of gender, exertion direction, angular velocity and wrist angle on simultaneous grip force and wrist torque under the isokinetic condition. The study used 20 participants (10 males and 10 females) and included 6 angular velocities (15, 30, 45, 60, 75, and 90 degrees /s) and 2 wrist exertion directions (flexion and extension) over the wrist range of motion of 70 degrees flexion to 60 degrees extension in 5 degrees increments. Similar to other studies, males and flexion exertion produced larger forces than females and extension exertion, respectively. However, the largest forces were generated at near extreme flexion of the wrist and the dependent variable of angular velocity was not practically significant. These results can contribute to the evaluation of cumulative trauma syndromes, but there is a need for more research on the dynamic measures of the hand and wrist complex and for standard development for dynamic force measurement.

Adult↗

Cold effect on oxygen uptake, perceived exertion, and spasticity in patients with multiple sclerosis.

OBJECTIVE: To determine the effect of a cold bath (24 degrees C) on oxygen consumption and perceived exertion during ambulation and on spasticity in individuals with mild to moderate multiple sclerosis. DESIGN: A repeated-measures design with random assignment of experimental and control conditions. SETTING: Outpatient physical therapy department associated with an academic institution. PATIENTS: Fourteen individuals with clinically definite multiple sclerosis exhibiting spasticity and capable of ambulating at 0.7 m/sec on a motorized treadmill without handrail support. MEASUREMENT: Assessment of oxygen uptake, heart rate, and perceived exertion occurred during two 10-minute walks interspersed with a 30-minute rest on 2 separate days. Measurement of spasticity occurred three times during each session. RESULTS: Oxygen consumption and perceived exertion were unchanged. Spasticity was higher immediately (p < .05) after the cold bath. CONCLUSIONS: Increase in spasticity was statistically significant, but unlikely to be of any clinical importance. Contrary to our hypothesis, a cold bath (24 degrees C) for 20 minutes did not reduce oxygen consumption or rating of perceived exertion during ambulation.

Adult↗

Stress induces rapid changes in serotonergic activity: restraint and exertion.

Rapid activation of central serotonergic systems occurs in response to the social stress of aggression in dominant lizards. The most rapid expression of serotonergic activity occurs in nucleus accumbens, hippocampus and brainstem. To compare previously measured responses induced by social stressors with those provoked by physical stress, serotonergic activity was examined following restraint stress (handling) and forced physical exertion. After handling, some male Anolis carolinensis were placed on a race track and either run until there was no movement following 1 min of prodding, or half that time. Controls were killed without treatment. Lizards stressed by handling showed rapid (25 s) increases in serotonergic activity (5-HIAA/5-HT) in striatum, dorsal cortex, locus ceruleus, and nucleus accumbens. Other changes in serotonergic systems caused by stress occurred in raphe and hippocampus. Serotonergic changes induced by handling stress were reversed by exercise (to 50% maximal exertion time) in subiculum, striatum and nucleus accumbens. The serotonergic profile of lizards run until they would no longer respond to prodding (maximal exertion time) was significantly different from that for more acute exertion in hippocampus, subiculum, striatum, medial amygdala, locus ceruleus, area postrema, and raphe. Physical stress (handling) mimicked social stress by producing rapid serotonergic changes in hippocampus, subiculum, nucleus accumbens and locus ceruleus. In contrast, the medial amygdala, which has previously been demonstrated to respond serotonergically to social stress only after a temporal delay, did not show a rapid response to restraint stress.

Animals↗

Influence of the age on self regulation of static grip forces from perceived exertion values.

The investigation of self-regulation of grip force provides indirect cues about the developmental neurobiology of the subject. The aim of this study was to examine the ability of subjects of different ages to produce different forces based on their perceived exertion during a grip force task by using a test and a randomised re-test procedure. Eighteen young children (aged 6.5 years), 18 adolescents (13.5 years) and 18 adults (28.5 years) performed a graded hand grip strength test (GST) at four intensities. Perceived exertion (RPE-C) was recorded at the end of each load level. Then, subjects were scheduled for a randomised grip strength test performed in the same experimental conditions than GST. Statistical analysis revealed no significant effect in grip strength for test in the three groups. However, a significant main effect for intensities was obtained in the three groups (P < 0.0001). Significant correlations were observed between GST and RPE-C (r(2) = 0.62, P < 0.0001; r(2) = 0.53, P < 0.0001; r(2) = 0.51, P < 0.0001), in the children, adolescent and adult groups, respectively. However at low grip force intensities, it appears that children have some difficulties to rate their perceived exertion. The results of this study suggest that the neurodevelopmental level of 6-year-old children do not affect the ability to produce reliably moderate to intense forces from perceived exertion during a grip force task.

Adolescent↗

Observational assessment of forceful exertion and the perceived force demands of daily activities.

The primary objective of this study was to assess the accuracy and precision with which analysts observe and estimate the force produced as subjects performed exertions on a work simulator. Eight analysts observed 32 subjects and estimated force as a percent of subjects' maximum voluntary contraction (% MVC). Analysts exhibited bias toward the mean, as high force exertions (> 67% MVC) were underestimated (mean: 11.6% MVC) and low force exertions (<34% MVC) were overestimated (mean: 6.7% MVC). Average error for medium force exertions (34-67% MVC) was not statistically different from zero (2.1% MVC). For all force levels, precision of the estimate was very poor (standard deviation range: 16.2-20.7% MVC). Experience of the analyst in performing ergonomic analysis did not affect accuracy. A secondary objective of the study was to conduct a survey in which subjects identified activities of daily living they perceived as equivalent to controlled force levels. A total of 59 different activities ranging from minimal force required to near maximum were listed by at least 5% of the participants. This list may be used to assist health care practitioners and patients convey the force demands required of occupational tasks as well as for evaluating the diminished strength of the patient.

Activities of Daily Living↗

Complexities in ETS-domain transcription factor function and regulation: lessons from the TCF (ternary complex factor) subfamily. The Colworth Medal Lecture.

The ETS-domain transcription factor family can be divided into a series of subfamilies. Elk-1 represents the founding member of the ternary complex factor (TCF) subfamily. By focusing on the TCF subfamily, we can demonstrate the complexities that exist in the function and regulation of ETS-domain transcription factors. This article focuses on Elk-1 in detail and summarizes the functions of other TCFs. The key themes covered include the domain structure of the TCFs, the mechanisms of complex formation with serum response factor, regulation of TCFs by mitogen-activated protein kinase cascades, and transcriptional regulatory properties of the TCFs. Finally, the emerging role of the TCFs in vivo is discussed. A picture is developing indicating that, while these proteins exhibit significant sequence and functional conservation, key differences in their structure and regulation are being identified which may relate to unique functions of these proteins in vivo.

Amino Acid Sequence↗

Chiari-associated exertional, cough, and sneeze headache responsive to medical therapy.

Benign exertional headache is coded as a separate entity within the International Headache Society's classification system, but the pathophysiological mechanisms underlying this clinical headache subtype are unknown and possibly are similar to those generating migraine. Coexistence of migraine and benign exertional headache in the same patient is not unusual, and antimigraine pharmacologic treatments are often effective in both headache types. Regardless, optimal management mandates that the clinician exclude any intracranial or systemic disease that could mimic "primary" exertional headache. The same holds for primary headaches induced by coughing or sneezing; congenital malformations or neoplasms, particularly within the posterior fossa, are not rare in these patients. The neurologic examination may not be sufficiently sensitive to detect the offending lesion. We describe a patient with migraine without aura and exertional secondary headache due to Chiari malformation type I whose headaches responded to treatment with propranolol and indomethacin.

Adrenergic beta-Antagonists↗

Influence of aerobic fitness level on measured and estimated perceived exertion during exhausting runs.

The purpose of the present investigation was 1) to study the effects of fitness level on perceived exertion (RPE) and estimated time limit (ETL) scales during exhausting runs, and 2) to predict time to exhaustion from RPE or ETL values collected during a constant run exercise. Eight high-fitness level and twelve moderate-fitness level endurance trained males performed two exhausting exercises on a 400-m running track. The first test was a graded exercise using a portable metabolic system to determine maximal oxygen uptake (V.O (2)max), the velocity associated with V.O (2)max (vV.O (2)max), the velocity at the lactate threshold (vLT) and the velocity at delta 50 (vDelta50 : the velocity halfway between vV.O (2)max and vLT). The second test was a constant run exercise at vDelta50 to determine the time to exhaustion at this intensity (tlimvDelta50). Moderate-fitness level athletes perceived exercise to be relatively more strenuous and felt that they could continue for less time than high-fitness level athletes at similar relative velocities. There was no effect of fitness level on perceived exertion for a given relative exercise duration. RPE corresponding to vLT was not statistically significantly different between the two levels groups. For the two groups, measured and predicted exhaustion time values, which were calculated from linear extrapolation of RPE and ETL values collected during the first 4 minutes of a submaximal constant run exercise, were not statistically significantly correlated. These results indicate that the aerobic fitness level seems to influence perceived exertion only during graded exercise. Consequently, if RPE is used to prescribe an exercise intensity, the prescription must be individualised regarding the aerobic fitness level of the athlete except for exercise intensities corresponding to vLT. Moreover, the perceived exertion pattern at the beginning of a submaximal constant run exercise could not be considered as a sensitive predictor of the point of self-imposed exhaustion whatever the fitness level of the athletes.

Adult↗

Prolonged exercise at a constant load on a bicycle ergometer: ratings of perceived exertion and leg aches and pain as well as measurements of blood lactate accumulation and heart rate.

To study changes over time during prolonged exercise on a bicycle ergometer at a constant load, 22 healthy males rated perceived exertion as well as aches and pain in the legs, and measurements were taken on blood lactate accumulation and heart rate (HR). The prolonged exercise was carried out at WOBLA (the power level eliciting a blood lactate concentration of 4 mmol X l-1). All four measured variables, ratings of perceived exertion, ratings of aches and pain in the legs, blood lactate accumulation, and HR, grew systematically according to negatively accelerating functions. HR showed more of a steady state, whereas all the other three variables grew continuously over time. Three subgroups were identified related to the blood lactate response after 15 min at WOBLA: elevated (greater than 5 mmol X l-1), intermediate (3.5-4.9 mmol X l-1), and low (less than 3.4 mmol X l-1). It was suggested that a major contribution to the discrepancies in blood lactate between the subgroups after 15 min was partly due to insufficient warming up, which was 5 min at 20 W as compared with the final power level (WOBLA), which differed between 140 and 260 W. After 15 min both rated perceived exertion and rated aches and pain in the legs were related to the corresponding blood lactates. It was suggested that rated perceived exertion and rated aches and pain in the legs partly reflected the degree of "anaerobic" metabolism measured as blood lactate.

Adult↗

Physical exertion as a trigger of acute myocardial infarction. Triggers and Mechanisms of Myocardial Infarction Study Group.

BACKGROUND: It is controversial whether the onset of myocardial infarction occurs randomly or is precipitated by identifiable stimuli. Previous studies have suggested a higher risk of cardiac events in association with exertion. METHODS: Consecutive patients with acute myocardial infarction were identified by recording all admissions to our hospital in Berlin and by monitoring a general population of 330,000 residents in Augsburg, Germany. Information on the circumstances of each infarction was obtained by means of standardized interviews. The data analysis included a comparison of patients with matched controls and a case-crossover comparison (one in which each patient serves as his or her own control) of the patient's usual frequency of exertion with the last episode of exertion before the onset of myocardial infarction. RESULTS: From January 1989 through December 1991, 1194 patients (74 percent of whom were men; mean age [+/- SD], 61 +/- 9 years) completed the interview 13 +/- 6 days after infarction. We found that 7.1 percent of the case patients had engaged in physical exertion (> or = 6 metabolic equivalents) at the onset of infarction, as compared with 3.9 percent of the controls at the onset of the control event. For the patients as compared with the matched controls, the adjusted relative risk of having engaged in strenuous physical activity at the onset of infarction or the control event was 2.1 (95 percent confidence interval, 1.1 to 3.6). The case-crossover comparison yielded a similar relative risk of 2.1 (95 percent confidence interval, 1.6 to 3.1) for having engaged in strenuous physical activity within one hour before myocardial infarction. Patients whose frequency of regular exercise was less than four and four or more times per week had relative risks of 6.9 and 1.3, respectively (P < 0.01). CONCLUSIONS: A period of strenuous physical activity is associated with a temporary increase in the risk of having a myocardial infarction, particularly among patients who exercise infrequently. These findings should aid in the identification of the triggering mechanisms for myocardial infarction and improve prevention of this common and serious disorder.

Aged↗