The increased work of breathing associated with intense cycling has been identified as a factor that may negatively affect cycling performance. The aerodynamic position, abnormal respiratory mechanics either at rest or during exercise, and the development of a tachypnoeic breathing pattern are factors known to increase the work of breathing. Breathing pattern retraining aims to decrease the work of breathing by delaying the onset of dynamic hyperinflation and the recruitment of accessory breathing muscles. To date no studies have investigated the performance, physiological and perceptual consequences of manipulating breathing pattern in trained cyclists. Purpose: The aim of the present study was to investigate the effect of breathing pattern retraining on 20-km time trial performance and respiratory and metabolic measures in competitive cyclists. Method: Twenty-four competitive male cyclists (age 37.7 ± 8.6 years, mean ± SD; peak 4.34 ± 0.47 L·min-1) were match paired on 20-km time trial performance and assigned at random to either an intervention group (breathing pattern retraining; N = 12) or control group (N = 12). 20-km time trial performance, pulmonary function and the physiological and perceptual response during a maximal incremental cycle step test were assessed pre- and post-intervention. The intervention group underwent four weeks of specific breathing pattern retraining using exercises designed to reduce dynamic hyperinflation and optimise respiratory mechanics. The control group attended the laboratory once a week during this period and performed a 10 minute sub-maximal ride wearing a biofeedback breathing harness. The control group was led to believe the purpose for their participation was to investigate the effect that maximal exercise had on breathing pattern, and to test the reliability of the breathing harness. There was no attempt to modify the breathing pattern of the control group. Data were analysed using an MS Excel spreadsheet designed for statistical analysis. The uncertainty in the effect was expressed as 90% confidence limits and a smallest worthwhile effect of 1.0% was assumed. Results: The intervention group showed substantial improvements in 20-km time trial performance (-1.5 ± 1.1%) and incremental power (3.2 ± 3%). Additionally, breathing frequency (-13.2 ± 8.9%; -9.5 ± 8.4%), tidal volume (10.6 ± 8.5%; 9.4 ± 7.6%), inspiratory time (10.1 ± 8%; 9.4 ± 7.7%), breathing RPE (-30 ± 33.9%; -24.7 ± 28.1%) and leg RPE (-27.9 ± 38.5%; -24.7 ± 28.2%) were all positively affected at lactate threshold and lactate turn point. No positive changes were observed in the control group for 20-km time trial performance (0.0 ± 1.0%), incremental power (-1.4 ± 3.5%), breathing frequency (-1.6 ± 8.0%; -2.0 ± 7.9%), tidal volume (0.9 ± 7.2%; 2.9 ± 9.4%), breathing RPE (16.1 ± 50.2%, 24.8 ± 43%) or leg RPE (13.4 ± 39.6%; 19.9 ± 43.2%) . Conclusion: These results provide evidence of the performance enhancing effect of four weeks of breathing pattern retraining in cyclists. Furthermore, they suggest breathing pattern can be retrained to exhibit a controlled pattern, without a tachypnoeic shift, during high intensity cycling. Additionally, these results indicate breathing pattern retraining attenuates the respiratory and peripheral perceived effort during incremental exercise. Key words: Breathing pattern disorders, retraining, blood stealing, cycling, performance, power output, respiratory mechanics, perceived exertion, 20km-TT

<p>The general aim of the thesis is to answer questions on general and differential aspects of perceived exertion and on the measurement of its intensity variation. Overall perceived exertion is commonly treated as a unidemensional construct. This thesis also explores its multidimensional character. Four empirical studies are summarized (Study I-IV). Psychophysical power functions of perceived exertion obtained with the new improved Borg CR100 (centiMax) scale were found to be consistent with results obtained with absolute magnitude estimation, and with the classical Borg CR10 and RPE scales. Women gave significantly higher perceived exertion scale values than men for the same levels of workload on a bicycle ergometer. This agrees with the fact that they were physically less strong than men. With regard to the measurement of “absolute” levels of intensity, RPE- and CR-scale values were validated by physiological measurements of heart rate and blood lactate. Predicted values of maximal individual performance obtained from psychophysical functions agreed well with actual maximal performance on the bicycle ergometer. This confirms the validity of the RPE and CR scales for measuring perceptual intensity and their value for interindividual comparisons. To study the multidimensional character of perceived exertion, 18 symptoms were measured with a CR scale: in a questionnaire, and in bicycle ergometer work tests. Five factors were extracted for the questionnaire: (1) Muscles and joints; (2) Perceived exertion; (3) Annoyance/lack of motivation; (4) Head/stomach symptoms; and (5) Cardiopulmonary symptoms. Four factors were extracted for the bicycle max test: (1) Physical distress; (2) Central perceived exertion; (3) Annoyance/lack of motivation; (4) Local perceived exertion. The questionnaire is suggested for clinical use to let patients express a variety of symptoms. The thesis also resulted in improvements of the Borg CR100 scale. An extended use of the scale is recommended.</p>

The general aim of the thesis is to answer questions on general and differential aspects of perceived exertion and on the measurement of its intensity variation. Overall perceived exertion is commonly treated as a unidemensional construct. This thesis also explores its multidimensional character. Four empirical studies are summarized (Study I-IV). Psychophysical power functions of perceived exertion obtained with the new improved Borg CR100 (centiMax) scale were found to be consistent with results obtained with absolute magnitude estimation, and with the classical Borg CR10 and RPE scales. Women gave significantly higher perceived exertion scale values than men for the same levels of workload on a bicycle ergometer. This agrees with the fact that they were physically less strong than men. With regard to the measurement of “absolute” levels of intensity, RPE- and CR-scale values were validated by physiological measurements of heart rate and blood lactate. Predicted values of maximal individual performance obtained from psychophysical functions agreed well with actual maximal performance on the bicycle ergometer. This confirms the validity of the RPE and CR scales for measuring perceptual intensity and their value for interindividual comparisons. To study the multidimensional character of perceived exertion, 18 symptoms were measured with a CR scale: in a questionnaire, and in bicycle ergometer work tests. Five factors were extracted for the questionnaire: (1) Muscles and joints; (2) Perceived exertion; (3) Annoyance/lack of motivation; (4) Head/stomach symptoms; and (5) Cardiopulmonary symptoms. Four factors were extracted for the bicycle max test: (1) Physical distress; (2) Central perceived exertion; (3) Annoyance/lack of motivation; (4) Local perceived exertion. The questionnaire is suggested for clinical use to let patients express a variety of symptoms. The thesis also resulted in improvements of the Borg CR100 scale. An extended use of the scale is recommended.

The Borg Rating of Perceived Exertion (RPE) scale is a primary tool for researchers and practitioners in exercise science to describe the intensity level subjects are experiencing when participating in exercise sessions. It has recently been suggested that RPE is not simply the direct result of interpretation of physiological changes as originally postulated, but is also influenced by affect, past experience, and time to completion, a concept coined as teleoanticipation. The purpose of this study was to determine the role of teleoanticipation in a sedentary population, by examining the effect unexpected increases in exercise duration on rating of perceived exertion and affect during low intensity treadmill walking. Based on the findings of prior studies, it is expected that the unexpected duration session will elicit higher RPE values and lower affect scores as measured by the feeling scale (FS) than the expected duration session. Ten participants between the ages of 18 and 45 years participated in the study. All participants were sedentary or insufficiently active with respect to physical activity for at least six months prior to the beginning of the study. Only participants with low to moderate risk according to the American College of Sports Medicine (ACSM) guidelines were admitted. All volunteers participated in one familiarization session followed by two trials of treadmill exercise. The familiarization trial was used to determine the treadmill speed in subsequent trials. All experimental trials were 30 minutes in length in partial accordance with ACSM guidelines, but the third trial in each group was presented as being 20 minutes and was extended to 30 minutes using a deception procedure employed in related research. Participants were informed at the 20-minute mark that the session would be extended to 30 minutes. Speed remained constant during both experimental trials. RPE and heart rate were recorded every minute to preclude volunteers from noticing the difference an increased interest in RPE responses around the 20-minute mark. Affect was measured by way of the feeling scale (FS) every other minute during the experimental trials. Blood pressure was recorded every five minutes to ensure participant safety. Results indicated a significant main effect for time for RPE (p = 0.001); however, there was no significant main effect for time and no interaction for RPE (p > 0.05) and no significant main effect and no interaction for FS. The primary finding from this investigation was that unexpected exercise durations have no affect on RPE or FS at low intensities in untrained, sedentary populations. Results suggest there may be a threshold of intensity required for a teleoanticipatory effect. More research is needed to further compare these effects with those of moderately and highly trained populations in medium or high intensity situations.

The growing public health burden associated with insufficient physical activity has resulted in the development of numerous health initiatives and products aimed at stabilizing and reversing the negative trends reported in epidemiological literature. A relatively novel product that has only recently made its way to the market are wearable weights. These products are designed to be worn on the lower legs and arms along with regular clothing as a means to increase caloric expenditure. However, no research to date has tested the efficacy of this product. PURPOSE: Compare psychological responses within bouts of aerobic exercise that vary on intensity and the presence of wearable weights. METHODS: Seventeen (11 female, 6 male, mean age = 24 years, mean BMI = 25.0 ) healthy volunteers were tested for aerobic fitness on a treadmill to determine VO2 max (mean = 44 ml x kg-1 x min-1). Participants then completed eight 30-minute walking trials on a treadmill while three ratings of perceived exertion (RPE - overall, RPE - chest and breathing, and RPE - legs ) were monitored while walking at different speeds and with varying combination of upper and lower body wearable weights. The design included two intensities (slow walking and brisk walking) and four conditions (no weights, arm weights, leg weights, and arm and leg weights) for a total of eight experimental trials. RESULTS: Data were analyzed using ANOVA and pairwise comparisons. Analyses revealed RPE overall was significantly elevated (P < 0.05), as was RPE of the legs (p < 0.05) while wearing upper and lower weights in the brisk walk trial but not in the slow walk trial. CONCLUSIONS: Findings suggest that exercising while using wearable weights increases RPE for the legs and overall only during the faster walking trials. PRACTICAL APPLICATIONS: This finding suggests that physical activity associated with daily living could be enhanced through the wearing of weights that can be worn under clothing without increasing perceptions of effort. In contrast, findings relative to brisk walking suggest that any beneficial increase in energy expenditure is potentially offset by significantly increased effort.

Evaluation of inner/intra-systemic concatenations is becoming more popular. The application of complex systems theories for differently trained people may boost the knowledge about the intersystem concatenations and may provide more information about functional state and perceived exertion. The aim of the research: To evaluate the connection between cardiovascular system’s functional parameters and perceived exertion during rest, physical task and recovery. Objectives of the study: 1. To assess perceived exertion during bicycle ergometer test. 2. To determine cardiovascular system‘s functional parameters of differently trained subjects during different test performance stages: rest, load and recovery. 3. To find out the correlations between perceived exertion and functional parameters of cardiovascular system during rest, load and recovery. Contingent and methods: We had 57 young volunteers aged (22.75 ± 0,4 year) participating in this study. We divided participants according the trained feature in 4 groups: endurance (n=12, 23±0.35 year), endurance-celerity group (n=16, 20.5±0.55 year), strength group (n=10, 24.3±0.53 year) and non-active group (n=19, 23.21±2.22 year). Methods: Endurance group went through constant load until volitional exhaustion. Celerity-endurance, strength and non-active groups went through incremental loading where the increase was made every minute by 50 W. The perceived exertion was measured every 15 seconds with Borg (RPE6-20) scale. Ongoing... [to full text] / Populiarėjant sistemų sąveikų analizei, daugiau dėmesio skiriama sąsajų tarp skirtingų sistemų nustatymui bei vertinimui. Kompleksinių sistemų teorijos pritaikymas skirtingai adaptuotiems asmenims gali suteikti daugiau informacijos apie jų funkcinį pajėgumą bei suvokiamas pastangas. Darbo tikslas: Įvertinti suvokiamų pastangų ir širdies ir kraujagyslių sistemos funkcinių rodiklių ramybės, fizinio krūvio ir atsigavimo metu. Tyrimo uždaviniai: 1. Nustatyti suvokiamas pastangas atliekant veloergonometrinį testą. 2. Nustatyti širdies kraujagyslių sistemos funkcinių rodiklių kitimą ramybės, fizinio krūvio ir atsigavimo metu tarp skirtingo kryptingumo fiziškai adaptuotų vyrų. 3. Nustatyti koreliacijas tarp suvokiamų pastangų ir širdies kraujagyslių sistemos funkcinių rodiklių ramybės, fizinio krūvio ir atsigavimo metu. Tiriamųjų kontingentas: Tiriamųjų kontingentą sudarė 57 jauno amžiaus vyrai, kurių amžiaus vidurkis tyrimo pradžioje buvo 22,75 ± 0,41 metai. Tiriamieji buvo suskirstyti į keturias grupes pagal treniruojamą fizinę ypatybę: ištvermės grupė (n=12, amžius 23±0,35metai), greičio-ištvermės grupė (n=16, amžius 20,5±0,55 metai), jėgos grupė (n=10, amžius 24,3±0,53 metai) ir nesportuojančiųjų grupė (n=19, amžius 23,21±2,22 metai). Tyrime taikyti metodai: Ištvermės grupė atliko ištvermės mėginį, važiuodami pastoviu krūviu (W) iki išsekimo, greičio-ištvermės, nesportuojančiųjų bei jėgos grupės atliko pakopomis didėjančio fizinio krūvio mėginį, kur apkrova buvo keičiama kas... [toliau žr. visą tekstą]

The increased work of breathing associated with intense cycling has been identified as a factor that may negatively affect cycling performance. The aerodynamic position, abnormal respiratory mechanics either at rest or during exercise, and the development of a tachypnoeic breathing pattern are factors known to increase the work of breathing. Breathing pattern retraining aims to decrease the work of breathing by delaying the onset of dynamic hyperinflation and the recruitment of accessory breathing muscles. To date no studies have investigated the performance, physiological and perceptual consequences of manipulating breathing pattern in trained cyclists. Purpose: The aim of the present study was to investigate the effect of breathing pattern retraining on 20-km time trial performance and respiratory and metabolic measures in competitive cyclists. Method: Twenty-four competitive male cyclists (age 37.7 ± 8.6 years, mean ± SD; peak 4.34 ± 0.47 L·min-1) were match paired on 20-km time trial performance and assigned at random to either an intervention group (breathing pattern retraining; N = 12) or control group (N = 12). 20-km time trial performance, pulmonary function and the physiological and perceptual response during a maximal incremental cycle step test were assessed pre- and post-intervention. The intervention group underwent four weeks of specific breathing pattern retraining using exercises designed to reduce dynamic hyperinflation and optimise respiratory mechanics. The control group attended the laboratory once a week during this period and performed a 10 minute sub-maximal ride wearing a biofeedback breathing harness. The control group was led to believe the purpose for their participation was to investigate the effect that maximal exercise had on breathing pattern, and to test the reliability of the breathing harness. There was no attempt to modify the breathing pattern of the control group. Data were analysed using an MS Excel spreadsheet designed for statistical analysis. The uncertainty in the effect was expressed as 90% confidence limits and a smallest worthwhile effect of 1.0% was assumed. Results: The intervention group showed substantial improvements in 20-km time trial performance (-1.5 ± 1.1%) and incremental power (3.2 ± 3%). Additionally, breathing frequency (-13.2 ± 8.9%; -9.5 ± 8.4%), tidal volume (10.6 ± 8.5%; 9.4 ± 7.6%), inspiratory time (10.1 ± 8%; 9.4 ± 7.7%), breathing RPE (-30 ± 33.9%; -24.7 ± 28.1%) and leg RPE (-27.9 ± 38.5%; -24.7 ± 28.2%) were all positively affected at lactate threshold and lactate turn point. No positive changes were observed in the control group for 20-km time trial performance (0.0 ± 1.0%), incremental power (-1.4 ± 3.5%), breathing frequency (-1.6 ± 8.0%; -2.0 ± 7.9%), tidal volume (0.9 ± 7.2%; 2.9 ± 9.4%), breathing RPE (16.1 ± 50.2%, 24.8 ± 43%) or leg RPE (13.4 ± 39.6%; 19.9 ± 43.2%) . Conclusion: These results provide evidence of the performance enhancing effect of four weeks of breathing pattern retraining in cyclists. Furthermore, they suggest breathing pattern can be retrained to exhibit a controlled pattern, without a tachypnoeic shift, during high intensity cycling. Additionally, these results indicate breathing pattern retraining attenuates the respiratory and peripheral perceived effort during incremental exercise. Key words: Breathing pattern disorders, retraining, blood stealing, cycling, performance, power output, respiratory mechanics, perceived exertion, 20km-TT

O presente estudo teve por objetivo obter evidências da validade de identificação dos limiares de lactato e de percepção subjetiva de esforço (PSE) em teste de campo, comparando com o desempenho, em ciclistas de estrada. Esta é uma modalidade em que a aptidão aeróbia é uma importante determinante de desempenho; porém, haja vista que o VO2máx parece sofrer poucas alterações com o treinamento, são interessantes outras variáveis que permitam um efetivo e acessível planejamento e controle do treinamento. Testes de campo respeitam a especificidade do treinamento, avaliando atletas em situações próximas da realidade do esporte. Neste sentido, as concentrações de lactato sangüíneo ([La]) e a PSE parecem ferramentas eficazes através de seus limiares e correspondentes valores de FC e velocidade. Foram realizados dois testes: avaliação do desempenho (Teste de 40 km) e um teste de campo com intensidades crescentes controladas por valores fixos de FC (135±5, 145±5, 155±5, 165±5 bpm e esforço máximo), em circuito de 5 km, com registro das velocidades, [La], FC e PSE e posterior identificação dos limiares através do método Dmáx. Os LL também foram identificados a partir de concentrações fixas de 2, 3 e 4 mmol.L-1. A normalidade da amostra foi determinada por Kolmogorov-Smirnov; a comparação entre os métodos de identificação dos limiares em campo através de ANOVA de Um Fator e a comparação das relações entre os limiares obtidos nos testes CR-40 km e 5x5 km pela Correlação de Pearson, além do Teste de Friedman para comparação entre as médias dos limiares. Os resultados demonstraram a possibilidade de utilização do LL4 como preditor de desempenho, além de indicarem associações significativas entre a FC e a PSE e entre La e FC / The present study had the objective to obtain validity evidences of identificating lactate and rate of perceived exertion (RPE) metabolic thresholds in field tests, comparing them to performance, in road cyclists. Road cycling is a sport in which aerobic condition is an important performance determinant; however, considering that VO2max seems not to change with the training season, it is necessary that other condition markers can be used, leading, this way, to an effective and acessible training plan and control. Field tests respect the training principle of specificity, evaluating athletes in situations as closest as possible from the sports reality. Concerning to this, blood lactate concentrations ([La]) and RPE have shown to be efficient tools for that, throughout the identification of their thresholds and corresponding heart rate and velocity values. Cyclists developed a performance test (40 km TT) and a field test in which intensity was controled by HR fixed values (135±5, 145±5, 155±5, 165±5 bpm and maximal effort), in a 5 km extension circuit, with velocities, [La], HR, and RPE records, and posterior thresholds identification by the Dmax method. LT were also identified from fixed [La] of 2, 3, and 4 mmol.L-1. The sample degree of normality was determined by the Kolmogorov-Smirnov test; the comparision between the field thresholds identification methods were calculated by One-Factor ANOVA, and the comparision of the relationship between the thresholds obtained in the CR40 and in the field tests by Pearsons correlation, besides the use of Friedman test for comparing the thresholds mean values. Results presented the possibility of utilizing LL4 in order to predict performance in field tests, and also showed a significative association between HR and RPE and La and HR

O método Pilates, o qual vem se difundindo muito nas últimas décadas, é um método de condicionamento físico que apresenta uma série de exercícios sistematizados os quais podem ser realizados com aparelhos, dotados de molas, submetendo os músculos a cargas externas. Um desses exercícios é o leg work que pode ser caracterizado como uma extensão de quadril e joelhos. Dessa maneira, o conhecimento das forças envolvidas no exercício, bem como seu comportamento, ao longo da amplitude de execução permite uma melhor definição do exercício, contribuindo para uma escolha mais criteriosa e uma melhor prescrição do exercício. Assim, este estudo tem como objetivo identificar a diferença no exercício leg work executado nos aparelhos Chair e Reformer levando em consideração a carga do equipamento (força das molas), a amplitude de movimento (ADM), o ritmo de execução, a atividade eletromiográfica (EMG) de músculos específicos se a sensação subjetiva de esforço das executantes. A amostra foi composta por 18 mulheres fisicamente ativas sem histórico de lesão e praticantes de Pilates há pelo menos 6 meses. Foi empregado diagrama de corpo livre e equações de Newton-Euler para calcular a variação da força externa nos aparelhos Chair e Reformer no movimento leg work. Foi utilizada cinemetria bidimensional (2D) e dois eletromiógrafos para aquisição dos dados. Os músculos analisados foram glúteo máximo (GM), bíceps femoral (BF), vasto lateral (VL), reto femoral (RF), gastrocnêmio medial (GAS), oblíquo externo (OE) e multífido (MU). Os resultados indicam que há diferenças significativas na ativação EMG do OE, VL e RF, no índice de co-contração de BF-RF, BF-VL e OE-MU bem como no índice de esforço percebido entre aparelhos Chair e Reformer durante o movimento leg work. Isso provavelmente se deve a diferenças na ADM e nas estratégias de recrutamento, uma vez que a carga do equipamento final imposta era a mesma em ambos os aparelhos. Essas informações devem ser levadas em consideração em um programa de condicionamento e reabilitação de Pilates. Pode-se concluir que há diferenças no exercício leg work executado nos aparelhos Chair e Reformer na atividade EMG de músculos específicos, ADM e sensação subjetiva de esforço das executantes. / The Pilates method, which has been popularized over the last decades, is a physical conditioning method that presents a series of systematized exercises that may be performed by apparatus with springs, loading the muscles to external loads. One of these exercises is the leg work, that may be characterized as hip and knee extension. The knowledge of forces involved in an exercise, as well as their behavior throughout the range of execution allows a better exercise definition, contributing to a more careful choice and a better prescription of the exercise. So, the main goal of this study is to identify the difference between legwork exercise performed on Chair and Reformer apparatus, taking into account external load (spring force), range of motion (ROM), rhythm of execution, specific muscles electromyography (EMG) and subject‟s perceived exertion effort sensation. Eighteen women took part of the study, all physically active, without injury history and practitioners of Pilates for at least six months. Free body diagram and Newton-Euler equations were used in order to calculate external force variation on Chair and Reformer apparatus during the legwork movement. Two-dimensional (2D) kinematics and two electromyography were used for data acquisition. The muscles analyzed were Gluteus Maximum (GM), Biceps Femoris (BF), Vastus Lateralis (VL), Rectus Femoralis (RF), Gastrocnemius (GAS), External Obliquies (EB) and Multifidus (MU). Results indicate that there are significant differences in EMG activation of EB, VL and RF, in co-contraction index BF-RF, BF-VL and EB-MU, as well as in perceived exertion sensation between Chair and Reformer apparatus during the legwork movement. This is probably due to differences in the ROM and recruiting strategies, once the imposed final external load was the same for both apparatus. This information should be considered in conditioning and rehabilitation program in Pilates. It‟s possible to conclude that there are differences between legwork exercise performed on Chair and Reformer apparatus in relation to EMG activity of specific muscles, ROM and related Borg perceived exertion scale.

O objetivo do presente estudo foi verificar as relações entre a percepção de esforço (PE) e diferentes cargas em exercícios de força (EF), em sujeitos adultos sedentários, ativos e treinados. Trinta homens com idade entre 18 e 34 anos, foram divididos em três grupos experimentais (GE) de 10 sujeitos cada, sendo os mesmos classificados pelo seu histórico recente (12 meses) de prática de exercícios físicos: grupo de sedentários (GSE), grupo de treinados em força (GTF) e o grupo de fisicamente ativos (GAT). A avaliação da força máxima foi estabelecida através do teste de uma repetição máxima (1RM) nos EF supino (SUP) e pressão de pernas (PP). Através da realização de séries de 12 repetições, diferentes cargas foram aplicadas até que os 4 índices de esforço percebido (IEP – 11, 13, 15 e 17 da Escala RPE de Borg) fossem determinados. O ritmo foi controlado (3 segundos para cada repetição), as cargas foram ocultas, os intervalos controlados (3 a 5 minutos), a ordem dos IEP randomizados, a PE localizada e determinada após a realização da série. Após identificada a carga correspondente à cada IEP, a mesma foi relativizada em percentuais pelo teste de 1RM correspondente (%1RM). A análise estatísitica foi realizada através da análise de variância com bloqueamento e pela correlação de Spearman, sendo o nível de significância de p < 0,05, com os dados processados no software SPSS v. 13. Os resultados indicaram altas (r = 0,826 a 0,922) e significativas (p < 0,05) correlações entre os IEP e o %1RM, conforme GE e EF. Um comportamento similar foi encontrado entre os EF. Maiores cargas estão relacionadas com maiores IEP, sendo diferenciado entre os GE. O GTF utiliza um maior %1RM em relação ao GSE, enquanto que o GAT, apresentou um comportamento intermediário em relação aos demais grupos. Menor variabilidade das respostas do %1RM é verificada nos IEP maiores. Desta forma, acreditamos que a utilização da percepção de esforço pode ser um instrumento confiável na mensuração da intensidade do treinamento de força. / The aim of this study was to verify the relationship between the perceived exertion (PE) and different intensity in strength exercise (SE), in sedentary, active and trained adults subjects. Thirty males with 18 and 34 years old, were matched in 3 experimental groups (EG) with 10 subjects in each group, classified for their recent description (12 months) of physical exercises activities: sedentary group (GSE), strength training group (GST) and the physically active group (GPA). The maximum strength was measured through the 1 repetition maximum test (1RM) on the bench press and leg press exercise. With the accomplishment of sets of 12 repetitions, different loads were applied until the 4 ratings of perceived exertion (Borg’s RPE Scale - 11, 13, 15 and 17 ratings) were determined. The rhythm was controlled (3 seconds for each repetition), the loads were blinded to subjects, the intervals were controlled (3 - 5 minutes), the order of the RPE and exercise were randomized, and the active muscular PE were assessed following each set. After determination of corresponding load to each RPE, it was related by percentages for the corresponding 1RM (%1RM). Statistical analysis was carried by analysis of variance with lock-in and for the correlation of Spearman, with significant level p < 0,05, processing wit SPSS v. 13 software. The results indicated high (r = 0,826 a 0,922) and significant (p < 0,05) correlation between RPE and %1RM, as EG and SE. Similar results were found between the SE. Higher loads are related with higher RPE, with different behavior between EG. The GST uses higher %1RM in relation to the GSE, while the GAT, presented an intermediate behavior related to the other groups. Lower variability of responses of %1RM is observed in higher RPE. Thus, we believe that utilization of perception exertion can be a trustworthy instrument in the measurements of intensity in strength training.