Fernando dos Santos Nogueira

Modelos para predição da carga máxima no teste clínico de esforço cardiopulmonar

OBJECTIVE This study sought to derive generalized equations for predicting maximal workload for young men and women. METHODS Direct ergospirometry (Aerosport TEEM 100, USA) was used to determine VO2máx and the maximal work load (Wmax) on the cycle ergometer test (Monark,Brazil) of thirty men (25 +/- 5 years, 75.0 +/- 10.7 kg; 48.4 +/- 8.8 mL x kg(-1) x min(-1) and 243 +/- 51 Watts) and thirty women (26 +/- 5 years, 56.7 +/- 5.9 kg, 39.8 +/- 7.6 mL x kg(-1) x min(-1) and 172 +/- 37 Watts). Age and body mass were used as independent variables. For all statistic tests, a p < 0.05 significance level was adopted. RESULTS In the multiple linear adjustment, the maximal workload was explained by age and body mass as 54% (r = 0.73) for men, and as 76% (r = 0.87) for women, with standard errors of 0.66 W x kg(-1) and 25 Watts. The proposed equations were cross-validated using another sample with similar age and VO2máx characteristics comprised of fifteen men and fifteen women. The intraclass correlation between the predicted Wmax values and those measures by ergospirometry were 0.70 and 0.69, with standard errors of 28.4 and 15.8 Watts, respectively, for men and women. CONCLUSIONS This study exhibits valid generalized equations for determining the maximal cycle ergonometer workload for men and women.

Influência do protocolo ergométrico na ocorrência de diferentes critérios de esforço máximo

INTRODUCTION AND OBJECTIVES: The aim of this study was to investigate the influence of different exercise protocols in the onset of maximal effort parameters. METHODS: Nine healthy individuals (23 ± 4 year old; 177 ± 10 cm; and 77.1 ± 16 kg) participated in three progressive exercise tests (PR1 - 15 W•min-1, PR2 - 50 W•3 min-1, and PR3 - 50 W•5 min-1) in a cycle ergometer. Oxygen consumption was measured in open circuit and was calculated at 20 s intervals. The maximal effort parameters considered here were: plateau in oxygen consumption 95% predicted by age; blood lactate concentration (8.0 mM; and RER > 1.1. RESULTS: The VO2max was not different among exercise tests (2.68 ± 1.0; 2.58 ± 1.0 and 2.99 ± 1.3 L•min-1 for PR1; PR2 and PR3, p = 0.72). The highest plateau occurrence was in PR1 (5 individuals). The heart rate criterion was observed in 3 individuals in PR3, while the lactate criterion was fulfilled in 6 subjects in the same PR3 protocol. Regarding the RER parameter, only 6 subjects in PR1 achieved values > 1.1. CONCLUSION: It was concluded that the maximal effort parameters evaluated in this study are influenced by the exercise test, even when there are no differences in the VO2max

Resposta da cinética de consumo de oxigênio e da eficiência mecânica delta de homens e mulheres em diferentes intensidades de esforço

ABSTRACT INTRODUCTION AND OBJECTIVE:Delta efficiency (DE) and oxygen uptake kinetics (K2) are influenced by muscle metabolic parameters and oxygen transport. The aim of this study was to determine the difference in DE and K2 in three effort intensities in both genders. METHODS: Fifty-six subjects (26 women) were submitted to a graded maximal exercise test (GXT) on cycle ergometer to determine the maximum oxygen uptake ( 2max ), maximal power output (Wmax), anaerobic threshold (AT) and respiratory compensation point (RCP). The AT and RCP were determined using the V-slope and E / 2 methods; the RCP using the relationship 2versus E both by two investigators. The DE and K2 have been considered as a slope between 2versus Watts and 2versus time (s), respectively, from the beginning of test until AT (S1), from AT to RCP (S2) and from RCP to 2max (S3), determined by linear regression analysis. RESULTS: Regarding DE, significant differences were observed between S1 versus S2 (p = 0.001), S1 versus S3 (p = 0.001) and S2 versus S3 (p = 0.006). There was no significant difference (p = 0.060) or interaction (p = 0.062) between men and women. For K2, significant differences were observed between S1 versus S3 (p = 0.001) and S2 versus S3 (p = 0.001) in both genders. Significant differences (p = 0.001) and interaction (p = 0.006) were observed between men and women, in the last parameter. CONCLUSIONS: DE decreases with increasing intensity of power output, but there are no differences when comparing men and women. On the other hand, women present faster K2than men

Measurement precision of the anaerobic threshold by means of a portable calorimeter

BACKGROUND Many methods are used for determining the Anaerobic Threshold (AT) by means of sophisticated ergospirometer. OBJECTIVE To test the AT variation, detected by mathematical models and visual inspection, when low cost ergospirometer is used and intended for clinical application. METHODS Seventy nine apparently healthy subjects were volunteers in this study; from these, 57 men. The VO₂(max) and the ventilatory threshold were determined by indirect, open-circuit calorimetry. The electro-enzymatic method was used for analyzing the lactacidemia and direct determination of the Lactate Threshold (LT). The AT was determined by two mathematical methods (MM(RSS) and MM(slope)), based on the gases exchange, and by the log-log visual method, for determining the LT. Two independent investigators determined the AT through visual inspection of three graphs, considering two methods (AT₋(a)= V-slope, EqV; and AT₋(b) = V-slope, EqV and ExCO₂). The data were analyzed by means of parametric statistics for determining the differences between AT₋(a) versus ExCO₂, MM(RSS) and MM(slope); AT-b versus MM(RSS) and MM(slope); and LT versus AT₋(a), AT₋(b), MM(RSS) and MM(slope). RESULTS The MM(slope) was the only method that presented a significant difference between the AT₋(a) and AT₋(b) (p=0.001), with CV% >15. LT versus MM(slope) did not present significant difference (p=0.274), however, it was observed a high CV (24%). CONCLUSION It was concluded that with the low cost equipment, the MM(RSS) and AT₋(a) methods can be used for determining the TAn. The MM(slope) method did not present satisfactory precision to be employed with this equipment.FUNDAMENTO: Muchos metodos se emplean para que se determine el Umbral Anaerobio (UAn) por medio de ergoespirometros sofisticados. OBJETIVO: Probar la variacion en el UAn, detectado por modelos matematicos y de inspeccion visual, cuando empleado ergoespirometro de bajo costo y destinado a la aplicacion clinica. METODOS: Fueron voluntarios para este estudio 79 individuos aparentemente sanos; de ellos, 57 varones. El VO2max y el umbral ventilatorio se determinaron por calorimetria indirecta de circuito abierto. El metodo electroenzimatico se empleo para analisis de lactacidemia y determinacion directa del umbral de lactato (UL). El UAn fue determinado por dos metodos matematicos (MMSQR y MMslope), basados en los cambios gaseosos, y por el metodo de inspeccion visual del log-log, para determinacion del UL. Dos investigadores independientes determinaron el UAn a traves de la inspeccion visual de tres graficos, teniendo en cuenta dos metodos (UAn-a= V-slope, EqV; y UAn-b = V-slope, EqV y ExCO2). Los datos se analizaron por medio de la estadistica parametrica para determinacion de las diferencias entre UAn-a versus ExCO2, MMSQR y MMslope; UAn-b versus MMSQR y MMslope; y UL versus UAn-a, UAN-b, MMSQR y MMslope. RESULTADOS: El MMslope fue el unico metodo que presento diferencia significativa entre el UAn-a y UAn-b (p=0,001), con CV% >15. El UL versus MMslope no presento diferencia significativa (p=0,274), con todo, se observo un elevado CV (24%). CONCLUSION: Se concluyo que con el equipamiento de bajo costo los metodos MMSQR y UAn-a pueden utilizarse para la determinacion del UAn. El metodo MMslope no presento precision satisfactoria para ser empleado con estos equipamientos.

Taurine supplementation improves economy of movement in the cycle test independently of the detrimental effects of ethanol

Taurine (TA) ingestion has been touted as blunting the deleterious effects of ethanol (ET) ingestion on motor performance. This study investigated the effects of ingestion of 0.6 mL·kg-1 of ET, 6 grams of TA, and ethanol in combination with taurine (ET+TA) on economy of movement (EM) and heart rate (HR). Nine volunteers, five female (22 ± 3 years) and four male (26 ± 5 years), participated in a study that used a counterbalanced experimental design. EM and HR were measured for 6 min while the subjects were pedalling at a fixed load 10% below the anaerobic threshold. The blood alcohol concentration (BAC) was similar between ET and ET+TA treatments at 30 min after ingestion and after exercise (12.3 mmol·L-1 vs. 13.7 mmol·L-1, and 9.7 mmol • L-1 vs 10.9 mmol·L-1, respectively). EM was significantly different among treatments, with lower mL·W-1 following ingestion of TA (-7.1%, p<0.001) than placebo and ET+TA (-2.45%, p=0.001) compared to ET. HR (bpm) was significantly (p<0.05) higher for ET (137 ± 14 bpm) than the other three treatments (placebo = 129 ± 14 bpm; TA = 127 ± 11 bpm; TA+ET = 133 ± 12 and ET = 137 ± 14 bpm). Taurine improved EM when compared to placebo or ET, and reduced HR when compared to ET. The combination of ET+TA also enhanced EM compared to placebo, and reduced HR in comparison to ET alone. Therefore, these findings indicate that taurine improves EM and counteracts ethanol-induced increases in HR during submaximal exercise.

Predição da massa corporal magra de adultos brasileiros através da área muscular do braço

INTRODUCCION: El area muscular del brazo (Amb) es componente de la masa corporal magra (MCM).OBJETIVO: Proponer una ecuacion para estimativa de la MCM a traves de Amb.METODOS: Cuarenta y cinco voluntarios masculinos, aparentemente saludables, con edad promedio de 22 ± 3 anos y masa corporal 74,9 ± 8,43 kg, fueron distribuidos aleatoriamente en grupos de validacion interna (VI) y validacion externa (VE). Tales sujetos fueron sometidos a medidas antropometricas y a hidrometria. Antes de los tests, los sujetos recibieron las siguientes orientaciones: a) evitar el consumo de cafeina y alcohol en las 24 horas precedentes; b) no realizar actividad fisica extenuante (≥ 5 METs), por lo menos en las 12 horas previas al examen y, c) periodo postprandial de cuatro horas. El area muscular del brazo fue determinada a traves de la ecuacion: Ama= [C-(T .π)]²÷(4 .π).RESULTADOS: El modelo derivado para prediccion fue: MCM= 9,127 + (0,625 . MC) + (0,139 . Amb); r2= 0,91, EPE= 1,85 kg (2,5% de la masa corporal o MC). Para VE, no hubo diferencia significativa entre la MCM medida por la electrobioimpedancia y la prevista por la formula de arriba (p=0,350), r²= 0,94, CV%= 2,0%, CCI= 0,97 y EPE= 1,87 kg.CONCLUSION: La ecuacion de regresion multiple derivada permite estimar la MCM de jovenes brasilenos del sexo masculino.Introduction: Arm muscle area (Ama) is a component of lean body mass (LBM). Objective: The objective of this study was to develop an equation for estimating LBM through the Ama. Methods: Forty-five apparently healthy young males, with an average age of 22 ± 3 years and body mass of 74.9 ± 8.43 kg, were randomly divided into two groups: internal validation (IV) and external validation (EV). The total sample was submitted to anthropometric and hydrometric measurements. Before the test, the subjects received the following instructions: a) to avoid caffeine and alcohol 24 hours before the test; b) not to do any strenuous physical activity (≥5 METs) for at least 12 hours prior to exam and; c) a postprandial period of 4 hours. Ama was obtained by the equation: Ama=[C(T . π) ]2 ÷ (4 . π). Results: The prediction model obtained was: LBM= 9.127 + (0.625 . BW) + (0.139 . Ama); r2=0.91; SEE=1.85 kg (2.5% BW). For the EV, no significant difference was found between LBM measured by BIA and that provided by the formula (p=0.35); r2= 0.94; CV%= 2.0%; ICC= 0.97 and SEE= 1.87 kg. Conclusion: The multiple regression equation enables the LBM to be estimated for young Brazilian males.

Prediction of lean body mass in Brazilian adults through arm muscle area

INTRODUCCION: El area muscular del brazo (Amb) es componente de la masa corporal magra (MCM).OBJETIVO: Proponer una ecuacion para estimativa de la MCM a traves de Amb.METODOS: Cuarenta y cinco voluntarios masculinos, aparentemente saludables, con edad promedio de 22 ± 3 anos y masa corporal 74,9 ± 8,43 kg, fueron distribuidos aleatoriamente en grupos de validacion interna (VI) y validacion externa (VE). Tales sujetos fueron sometidos a medidas antropometricas y a hidrometria. Antes de los tests, los sujetos recibieron las siguientes orientaciones: a) evitar el consumo de cafeina y alcohol en las 24 horas precedentes; b) no realizar actividad fisica extenuante (≥ 5 METs), por lo menos en las 12 horas previas al examen y, c) periodo postprandial de cuatro horas. El area muscular del brazo fue determinada a traves de la ecuacion: Ama= [C-(T .π)]²÷(4 .π).RESULTADOS: El modelo derivado para prediccion fue: MCM= 9,127 + (0,625 . MC) + (0,139 . Amb); r2= 0,91, EPE= 1,85 kg (2,5% de la masa corporal o MC). Para VE, no hubo diferencia significativa entre la MCM medida por la electrobioimpedancia y la prevista por la formula de arriba (p=0,350), r²= 0,94, CV%= 2,0%, CCI= 0,97 y EPE= 1,87 kg.CONCLUSION: La ecuacion de regresion multiple derivada permite estimar la MCM de jovenes brasilenos del sexo masculino.Introduction: Arm muscle area (Ama) is a component of lean body mass (LBM). Objective: The objective of this study was to develop an equation for estimating LBM through the Ama. Methods: Forty-five apparently healthy young males, with an average age of 22 ± 3 years and body mass of 74.9 ± 8.43 kg, were randomly divided into two groups: internal validation (IV) and external validation (EV). The total sample was submitted to anthropometric and hydrometric measurements. Before the test, the subjects received the following instructions: a) to avoid caffeine and alcohol 24 hours before the test; b) not to do any strenuous physical activity (≥5 METs) for at least 12 hours prior to exam and; c) a postprandial period of 4 hours. Ama was obtained by the equation: Ama=[C(T . π) ]2 ÷ (4 . π). Results: The prediction model obtained was: LBM= 9.127 + (0.625 . BW) + (0.139 . Ama); r2=0.91; SEE=1.85 kg (2.5% BW). For the EV, no significant difference was found between LBM measured by BIA and that provided by the formula (p=0.35); r2= 0.94; CV%= 2.0%; ICC= 0.97 and SEE= 1.87 kg. Conclusion: The multiple regression equation enables the LBM to be estimated for young Brazilian males.

Predicción de la masa corporal magra de adultos brasileños a través del área muscular del brazo

INTRODUCCION: El area muscular del brazo (Amb) es componente de la masa corporal magra (MCM).OBJETIVO: Proponer una ecuacion para estimativa de la MCM a traves de Amb.METODOS: Cuarenta y cinco voluntarios masculinos, aparentemente saludables, con edad promedio de 22 ± 3 anos y masa corporal 74,9 ± 8,43 kg, fueron distribuidos aleatoriamente en grupos de validacion interna (VI) y validacion externa (VE). Tales sujetos fueron sometidos a medidas antropometricas y a hidrometria. Antes de los tests, los sujetos recibieron las siguientes orientaciones: a) evitar el consumo de cafeina y alcohol en las 24 horas precedentes; b) no realizar actividad fisica extenuante (≥ 5 METs), por lo menos en las 12 horas previas al examen y, c) periodo postprandial de cuatro horas. El area muscular del brazo fue determinada a traves de la ecuacion: Ama= [C-(T .π)]²÷(4 .π).RESULTADOS: El modelo derivado para prediccion fue: MCM= 9,127 + (0,625 . MC) + (0,139 . Amb); r2= 0,91, EPE= 1,85 kg (2,5% de la masa corporal o MC). Para VE, no hubo diferencia significativa entre la MCM medida por la electrobioimpedancia y la prevista por la formula de arriba (p=0,350), r²= 0,94, CV%= 2,0%, CCI= 0,97 y EPE= 1,87 kg.CONCLUSION: La ecuacion de regresion multiple derivada permite estimar la MCM de jovenes brasilenos del sexo masculino.Introduction: Arm muscle area (Ama) is a component of lean body mass (LBM). Objective: The objective of this study was to develop an equation for estimating LBM through the Ama. Methods: Forty-five apparently healthy young males, with an average age of 22 ± 3 years and body mass of 74.9 ± 8.43 kg, were randomly divided into two groups: internal validation (IV) and external validation (EV). The total sample was submitted to anthropometric and hydrometric measurements. Before the test, the subjects received the following instructions: a) to avoid caffeine and alcohol 24 hours before the test; b) not to do any strenuous physical activity (≥5 METs) for at least 12 hours prior to exam and; c) a postprandial period of 4 hours. Ama was obtained by the equation: Ama=[C(T . π) ]2 ÷ (4 . π). Results: The prediction model obtained was: LBM= 9.127 + (0.625 . BW) + (0.139 . Ama); r2=0.91; SEE=1.85 kg (2.5% BW). For the EV, no significant difference was found between LBM measured by BIA and that provided by the formula (p=0.35); r2= 0.94; CV%= 2.0%; ICC= 0.97 and SEE= 1.87 kg. Conclusion: The multiple regression equation enables the LBM to be estimated for young Brazilian males.

Precisão da medida do limiar anaeróbio por meio do calorímetro portátil

BACKGROUND Many methods are used for determining the Anaerobic Threshold (AT) by means of sophisticated ergospirometer. OBJECTIVE To test the AT variation, detected by mathematical models and visual inspection, when low cost ergospirometer is used and intended for clinical application. METHODS Seventy nine apparently healthy subjects were volunteers in this study; from these, 57 men. The VO₂(max) and the ventilatory threshold were determined by indirect, open-circuit calorimetry. The electro-enzymatic method was used for analyzing the lactacidemia and direct determination of the Lactate Threshold (LT). The AT was determined by two mathematical methods (MM(RSS) and MM(slope)), based on the gases exchange, and by the log-log visual method, for determining the LT. Two independent investigators determined the AT through visual inspection of three graphs, considering two methods (AT₋(a)= V-slope, EqV; and AT₋(b) = V-slope, EqV and ExCO₂). The data were analyzed by means of parametric statistics for determining the differences between AT₋(a) versus ExCO₂, MM(RSS) and MM(slope); AT-b versus MM(RSS) and MM(slope); and LT versus AT₋(a), AT₋(b), MM(RSS) and MM(slope). RESULTS The MM(slope) was the only method that presented a significant difference between the AT₋(a) and AT₋(b) (p=0.001), with CV% >15. LT versus MM(slope) did not present significant difference (p=0.274), however, it was observed a high CV (24%). CONCLUSION It was concluded that with the low cost equipment, the MM(RSS) and AT₋(a) methods can be used for determining the TAn. The MM(slope) method did not present satisfactory precision to be employed with this equipment.FUNDAMENTO: Muchos metodos se emplean para que se determine el Umbral Anaerobio (UAn) por medio de ergoespirometros sofisticados. OBJETIVO: Probar la variacion en el UAn, detectado por modelos matematicos y de inspeccion visual, cuando empleado ergoespirometro de bajo costo y destinado a la aplicacion clinica. METODOS: Fueron voluntarios para este estudio 79 individuos aparentemente sanos; de ellos, 57 varones. El VO2max y el umbral ventilatorio se determinaron por calorimetria indirecta de circuito abierto. El metodo electroenzimatico se empleo para analisis de lactacidemia y determinacion directa del umbral de lactato (UL). El UAn fue determinado por dos metodos matematicos (MMSQR y MMslope), basados en los cambios gaseosos, y por el metodo de inspeccion visual del log-log, para determinacion del UL. Dos investigadores independientes determinaron el UAn a traves de la inspeccion visual de tres graficos, teniendo en cuenta dos metodos (UAn-a= V-slope, EqV; y UAn-b = V-slope, EqV y ExCO2). Los datos se analizaron por medio de la estadistica parametrica para determinacion de las diferencias entre UAn-a versus ExCO2, MMSQR y MMslope; UAn-b versus MMSQR y MMslope; y UL versus UAn-a, UAN-b, MMSQR y MMslope. RESULTADOS: El MMslope fue el unico metodo que presento diferencia significativa entre el UAn-a y UAn-b (p=0,001), con CV% >15. El UL versus MMslope no presento diferencia significativa (p=0,274), con todo, se observo un elevado CV (24%). CONCLUSION: Se concluyo que con el equipamiento de bajo costo los metodos MMSQR y UAn-a pueden utilizarse para la determinacion del UAn. El metodo MMslope no presento precision satisfactoria para ser empleado con estos equipamientos.

Precisión de la medición del umbral anaerobio por medio del calorímetro portátil

BACKGROUND Many methods are used for determining the Anaerobic Threshold (AT) by means of sophisticated ergospirometer. OBJECTIVE To test the AT variation, detected by mathematical models and visual inspection, when low cost ergospirometer is used and intended for clinical application. METHODS Seventy nine apparently healthy subjects were volunteers in this study; from these, 57 men. The VO₂(max) and the ventilatory threshold were determined by indirect, open-circuit calorimetry. The electro-enzymatic method was used for analyzing the lactacidemia and direct determination of the Lactate Threshold (LT). The AT was determined by two mathematical methods (MM(RSS) and MM(slope)), based on the gases exchange, and by the log-log visual method, for determining the LT. Two independent investigators determined the AT through visual inspection of three graphs, considering two methods (AT₋(a)= V-slope, EqV; and AT₋(b) = V-slope, EqV and ExCO₂). The data were analyzed by means of parametric statistics for determining the differences between AT₋(a) versus ExCO₂, MM(RSS) and MM(slope); AT-b versus MM(RSS) and MM(slope); and LT versus AT₋(a), AT₋(b), MM(RSS) and MM(slope). RESULTS The MM(slope) was the only method that presented a significant difference between the AT₋(a) and AT₋(b) (p=0.001), with CV% >15. LT versus MM(slope) did not present significant difference (p=0.274), however, it was observed a high CV (24%). CONCLUSION It was concluded that with the low cost equipment, the MM(RSS) and AT₋(a) methods can be used for determining the TAn. The MM(slope) method did not present satisfactory precision to be employed with this equipment.FUNDAMENTO: Muchos metodos se emplean para que se determine el Umbral Anaerobio (UAn) por medio de ergoespirometros sofisticados. OBJETIVO: Probar la variacion en el UAn, detectado por modelos matematicos y de inspeccion visual, cuando empleado ergoespirometro de bajo costo y destinado a la aplicacion clinica. METODOS: Fueron voluntarios para este estudio 79 individuos aparentemente sanos; de ellos, 57 varones. El VO2max y el umbral ventilatorio se determinaron por calorimetria indirecta de circuito abierto. El metodo electroenzimatico se empleo para analisis de lactacidemia y determinacion directa del umbral de lactato (UL). El UAn fue determinado por dos metodos matematicos (MMSQR y MMslope), basados en los cambios gaseosos, y por el metodo de inspeccion visual del log-log, para determinacion del UL. Dos investigadores independientes determinaron el UAn a traves de la inspeccion visual de tres graficos, teniendo en cuenta dos metodos (UAn-a= V-slope, EqV; y UAn-b = V-slope, EqV y ExCO2). Los datos se analizaron por medio de la estadistica parametrica para determinacion de las diferencias entre UAn-a versus ExCO2, MMSQR y MMslope; UAn-b versus MMSQR y MMslope; y UL versus UAn-a, UAN-b, MMSQR y MMslope. RESULTADOS: El MMslope fue el unico metodo que presento diferencia significativa entre el UAn-a y UAn-b (p=0,001), con CV% >15. El UL versus MMslope no presento diferencia significativa (p=0,274), con todo, se observo un elevado CV (24%). CONCLUSION: Se concluyo que con el equipamiento de bajo costo los metodos MMSQR y UAn-a pueden utilizarse para la determinacion del UAn. El metodo MMslope no presento precision satisfactoria para ser empleado con estos equipamientos.