The validity of Keiser-M3 stationary bicycle with standard ergometer for physiological measurements associated with maximum effort

Abstract Aim: This study aims to investigate the concordance between two cycle ergometers for variables measured in the test of maximum incremental effort. Methods: This correlation study enrolled 15 inactive women (19,2 ± 4,0 years old). At random, the participants performed two maximal effort incremental tests (MEIT), using cycle ergometers (Keiser-M3 and Ergo-167) on different days with a minimum interval of 72 hours. The test had stages of two minutes, and two-step increments were carried out at the end of each stage. Lactate concentration ([LAC]), and rated perceived exertion (RPE) were collected, in addition to monitoring oxygen uptake (VO2) and heart rate (HR). The Paired t-test was carried out to compare physiologic variables, Lin's test was used for correlation, and Bland Altman was used to measuring concordances among variables. Results: The correlations between physiologic parameters were considered strong for HR on the anaerobic threshold (Keiser M3 = 146 ± 14 bpm; Ergo-167 = 149 ± 9 bpm; r = 0.762), greater blood lactate value (Keiser M3 = 9,97 ± 2,51 mmol/L; Ergo-167 = 9.71 ± 2.56 mmol/L; r = 0.820), VO2max (Keiser M3 = 38,37 ± 6,97 mL/kg/min; Ergo-167 = 36.06 ± 8.4 mL/kg/min; r = 0,806) and HRmax (Keiser M3 = 186 ± 53 bpm; Ergo-167 = 188 ± 11 bpm; r = 0.716). Conclusion: The results show the feasibility of using the cycle ergometer Keiser, model M3, to perform the maximal effort incremental test, whereas there was high concordance in the physiologic responses in both ergometers for inactive women.

Agreement analysis between critical power and intensity corresponding to 50% ∆ in cycling exercise / Análise de concordância entre a potência crítica e a intensidade correspondente ao 50% ∆ no exercício de ciclismo

Abstract The purpose of this study was to determine the level of agreement between critical power (CP) and intensity corresponding to 50% of the difference (50% ∆) between oxygen uptake (VO2) at lactate threshold (LT) and maximal oxygen uptake (VO2max) in untrained subjects during cycling exercise. Fifteen healthy male subjects (age: 26.0 ± 3.5 years; body weight: 76.6 ± 10.4 kg; height: 178.2 ± 7.6 cm) volunteered to participate in the study. Each subject performed a series of tests to determine LT, VO2LT, CP, VO2CP, 50% ∆, VO250% ∆, and VO2max. The values LT, CP, VO2CP, 50% ∆, VO250% ∆ and VO2max were 109 ± 15 W, 1.84 ± 0.23 L.min-1, 207 ± 17 W, 2.78 ± 0.27 L.min-1, 206 ± 19 W, 2.77 ± 0.29 L.min-1, and 3.71 ± 0.49 L.min-1, respectively. No signficant difference was found between CP and 50% ∆ (t = 0.16; p = 0.87) or between VO2CP and VO250% ∆ (t = 0.12; p = 0.90). However, the bias ± 95% limits of agreement for comparison between CP and 50% ∆ and between VO2CP and VO250% ∆ were 1 ± 27 W (0.3 ± 14.1%) and 0.01 ± 0.24 L.min-1 (0.2 ± 8.9%), respectively. In summary, the mean CP and 50% ∆ values were not significantly different. However, considering the limits of agreement between the two intensities, CP estimated based on 50% ∆ might result in a remarkable error when the absolute variability of individual differences is taken into account.

Resumo A proposta deste estudo foi determinar o nível de concordância entre a potência crítica (PC) e a intensidade correspondente a 50% da diferença (50% ∆) entre o consumo de oxigênio (VO2) no limiar de lactato (LL) e o consumo máximo de oxigênio (VO2max) em sujeitos não treinados durante o exercício de ciclismo. Quinze sujeitos saudáveis do sexo masculino (idade: 26,0 ± 3,5 anos; massa corporal: 76,6 ± 10,4 kg; estatura: 178,2 ± 7,6 cm) participaram deste estudo. Cada sujeito realizou uma série de testes para determinar o LL, VO2.LL, PC, VO2.PC, 50% ∆, VO250% ∆ e VO2max. Os valores de LL, VO2LL, PC, VO2PC, 50% ∆, VO250% ∆ e VO2max foram 109 ± 15 W, 1,84 ± 0,23 L.min-1, 207 ± 17 W, 2,78 ± 0,27 L.min-1, 206 ± 19 W, 2,77 ± 0,29 L.min-1 e 3,71 ± 0,49 L.min-1, respectivamente. Nenhuma diferença significavita foi encontrada entre a PC e o 50% ∆ (t = 0.16; p = 0.87) e entre o VO2PC e o VO250% ∆ (t = 0.12; p = 0.90). Entretanto, o bias ± 95% dos limites de concordância para as comparações entre a PC e o 50% ∆ e entre o VO2PC e o VO250% ∆ foram 1 ± 27 W (0,3 ± 14,1%) e 0,01 ± 0,24 L.min-1 (0,2 ± 8,9%), respectivamente. Em resumo, os valores médios de PC e 50% ∆ não foram significativamente diferentes. No entanto, a PC estimada pelo 50% ∆ pode resultas em um erro significativo quando a cariabilidade individual absoluta é considerada.

Limiar anaeróbico de 4 mM é capaz de estimar a máxima fase estável de lactato de jogadores de futebol em testes de campo / Anaerobic threshold of 4.0mM is able to estimate the maximal lactate steady state of soccer players on the field tests

Diante à importância da capacidade aeróbia para o desempenho de jogadores de futebol, o Limiar Anaeróbio tem sido um parâmetro comumente utilizado para a avaliação desses atletas. Todavia, faltam informações a respeito da validade dos protocolos de campo adotados no meio futebolístico. Portanto, o objetivo do presente estudo foi comparar os valores de velocidade de corrida (VC) e frequência cardíaca (FC) associados à máxima fase estável de lactato (MFEL) e limiar anaeróbico de 4,0mM (OBLA), e verificar se uma concentração fixa de lactato de 4 mM pode ser utilizada para estimar a MFEL em jogadores de futebol em testes de campo. Para tanto 22 jogadores de futebol da categoria sub 20 anos (18,1 ± 0,2 anos) foram avaliados. O OBLA foi considerado como a VC correspondente a lactatemia de 4,0mM e a MFEL foi determinada por meio de exercícios submáximos de intensidade constante com duração de 30 minutos. Os resultados não demonstraram diferenças significativas entre VC e FC identificadas pela MFEL e OBLA e apresentaram correlação significativa entre VC identificada pela MFEL e OBLA (r=0,56; p<0,01). Conclui-se que a concentração fixa de lactato 4mM (OBLA) pode ser utilizada para estimar a VC associada à MFEL em jogadores de futebol em testes de campo. A FC deve ver utilizada com cautela quanto aplicada isoladamente para controle de intensidade.(AU)

Given the importance of aerobic capacity for the performance of soccer players, the Anaerobic Threshold has been a commonly parameter used to assess these athletes. However, there is missing information about the validity of field protocols adopted in the soccer environment. Therefore, the aim of this study was to compare the values of running speed (RS) and heart rate (HR) associated with the maximal lactate steady state (MLSS) and anaerobic threshold of 4.0mM (OBLA), and identify whether a fixed lactate concentration of 4 mM can be used to estimate the MLSS in soccer players in field tests. Twenty two soccer players of under 20 (18.1 ± 0.2 years) were evaluated. OBLA was taken as the RS corresponding to blood lactate concentration of 4.0 mM and MLSS was determined by sub maximal constant intensity exercise with a duration of 30 minutes. The results showed no significant differences between RS and HR identified by the MLSS and OBLA and showed significant correlation between the RS identified by MLSS and OBLA (r=0.56, p< 0.01). It is concluded that fixed concentration of 4 mM lactate (OBLA) can be used to estimate the RS associated with MLSS in soccer players in field tests. HR should be used with caution when applied separately for intensity control.(AU)

Diagnostic and Prognostic Value of Lactate Threshold and pH - Threshold Determination during Cardiopulmonary Testing in Patients with Chronic Heart Failure.

Objective: lactate threshold and pH-threshold determination during cardiopulmonary testing (CPET) and evaluate their diagnostic and prognostic value in patients with chronic heart failure. Methods: The study included 58 HF patients with NYHA class II-IV, who have performed CPET on treadmill using equipment «Oxycon PRO», Jaeger, Germany. Individual exercise test protocol (ramp protocol) was created for every participant. The cubital venous catheter was installed in all subjects before exercise test. Blood samples were taken at baseline and at 1-minute intervals during test. PH, lactate and HCO3- concentration were estimated using analyzer i-STAT, cartridge CG4 (Abbot, USA). Lactate threshold (LT) and pH-threshold (pH-T) were determined by changes in pH and lactate levels in correlation with dynamics of oxygen uptake (VO2), carbon dioxide output (VCO2), minute ventilation (VE), ventilatory equivalent of carbon dioxide (VE/VCO2), respiratory exchange ratio (RER). Respiratory compensation point (RCP) was determined, when ventilation dramatically increase relative VE/VCO2. Results: In HF patients with NYHA class II level of physical performance was significantly higher than in patients NYHA class III and IV. However, during exercise in all HF patients were observed similar physiological stages and compensatory mechanisms of regulation of homeostasis, but with varying of exercise intensity. In HF patient with NYHA class IV, exercise was stopped before reaching of RCP in connection with the development shortness of breath, weakness, tiredness, fatigue in the legs 8-9/10 Borg scale. Among HF patients with NYHA class III RCP reached 12 (36%) of people, among patients with class II - 14 (82%). The 95% confidence intervals (CI) for the VO2 peak, RCP, pH-T and LT in II, III and IV NYHA class are follows: in HF patients with NYHA class II - 17.4 to 18.2, 16.3 to 17.2, 14.7 to 15.3 and 9.7 to 10.1; NYHA class III - 13.5 to 14.3, 12.2 to 12.8, 11.4 to 11.8 and 8.2 to 8.6; NYHA class IV - 8.6 to 10.6 for VO2 peak, 8.1 to 9.7 for VO2 pHT, 5.7 to 7.5 for VO2 LT. HF NYHA class correlated with VO2 LT, VO2 pH-T and VO2 RCP, r=-0.7, p<0.01, r=-0.5, p<0.01 and r=-0.4, p<0.01, respectively. Patients were observed in the average 21.4 of +/ - 1.5 months (6-48). For the specified period in the study group died 15 HF patients (25%) with III-IV FC. We observed the following correlations: the survival and VO2 LT - r=0.8, p<0.05; survival and VO2 рН-T - r=0.5, p<0.05; survival and VO2 RCP - r=0.2, p<0.07. Conclusion: In HF patients with NYHA class II-IV significant diagnostic and prognostic markers are content VO2 at lactate threshold and pH-threshold, especially at the lactate threshold.

Maximal power output estimates the MLSS before and after aerobic training / Potência máxima estima a MFEL antes e após o treinamento aeróbio / Potencia máxima estima el MLSS antes y después del entrenamiento aerobio

The purpose of this study is to present an equation to predict the maximal lactate steady state (MLSS) through a VO2peak incremental protocol. Twenty-six physically active men were divided in two groups (G1 and G2). They performed one maximal incremental test to determine their VO2peak and maximal power output (Wpeak), and also several constant intensity tests to determine MLSS intensity (MLSSw) on a cycle ergometer. Group G2 underwent six weeks of aerobic training at MLSSw. A regression equation was created using G1 subjects Wpeak and MLSSw to estimate the MLSS intensity (MLSSweq) before and after training for G2 (MLSSweq = 0.866 x Wpeak-41.734). The mean values were not different (150±27W vs 148±27W, before training / 171±26W vs 177±24W, after training) and significant correlations were found between the measured and the estimated MLSSw before (r²=0.49) and after training (r²=0.62) in G2. The proposed equation was effective to estimate the MLSS intensity before and after aerobic training...

Este estudo propõe uma equação para predição da máxima fase estável de lactato (MFEL) através de um teste para medida do VO2pico. Vinte e seis homens fisicamente ativos foram divididos em dois grupos (G1 e G2). Eles realizaram um teste máximo para medida do VO2pico e potência máxima (Ppico) e testes submáximos para determinar a intensidade da MFEL (MFELw) em cicloergômetro. O grupo G2 treinou por seis semanas na MFELw. Uma equação de regressão linear foi desenvolvida utilizando os resultados do G1 (Ppico e MFELw) para estimativa da MFEL (MFELweq) antes e após o treinamento no G2 (MFELweq=0,866 x Ppico-41,734). Os valores médios não foram diferentes (150±27W vs 148±27W, pré-treino / 171±26W vs 177±24W, pós-treino) e encontrou-se uma correlação significativa entre a MFELw medida e estimada antes (r²=0,49) e após o treinamento (r²=0,62) no grupo G2. A equação proposta foi efetiva para estimar a MFEL antes e após o treinamento...

Este estudio propone una ecuación para la predicción del máximo estado estable de lactato (MLSS) a través de un test para medir VO2pico. Veintiséis hombres físicamente activos se dividieron en dos grupos (G1 y G2). Ellos realizaron un test máximo para medir el VO2pico y potencia máxima (Ppico) y testes submáximas para determinar la intensidad de la MLSS (MLSSw) en cicloergómetro. El grupo G2 entrenó por seis semanas en la MLSSw. Una ecuación de regresión lineal fue desarrollada utilizando los resultados del G1 (Ppico y MLSSw) para estimar la MLSS (MLSSweq) antes y después del entrenamiento en el G2 (MFELweq=0,866 x Ppico-41,734). Los valores medios no fueron distintos (150±27W vs 148±27W, pre-entrenamiento / 171±26W vs 177±24W, después del entrenamiento) y se encontró una correlación significativa entre la MFELw medida y estimada antes (r²=0,49) y después del entrenamiento (r²=0,62) en el G2. La ecuación propuesta fue eficaz para estimar la MLSS antes y después del entrenamiento...

Effect of pre-acclimatization training under hypoxic environment for one week on work capacity and physiological responses under hypoxic environment / 体力科学

We examined the effect of pre-acclimatization training under hypoxia for competition or training at high altitude on work capacity and physiological responses in hypoxia. Eight healthy male university students performed pre-acclimatization training under normobaric hypoxia (equivalent to about 2500 m; 15.4% inspired oxygen) for a week. Each student was exposed for a total of 90 minutes. During the exposure, each student rested for 60 minutes and pedaled at a workload of lactate threshold (LT) under normobaric hypoxia (equivalent to about 2500 m) for 30 minutes. In the result, workload of LT under normobaric hypoxia significantly increased after pre-acclimatization training (+15%). In physiological responses, arterial oxygen saturation at rest and exercise and peak ventilatory volume significantly increased after pre-acclimatization training. Arterial oxygen saturation at rest during pre-acclimatization training significantly increased. In addition, the ratio of low- and high-frequency power in heart rate variability significantly decreased after pre-acclimatization training. These results suggest that pre-acclimatization training is able to bring in acclimatization to high altitude on cardiopulmonary function and prevent decline of work capacity in high altitude. The ratio of low- and high-frequency power in heart rate variability as well as arterial oxygen saturation may reflect degree of acclimatization to high altitude.

INFLUENCE OF LOW GLYCOGEN STORAGE ON BLOOD GLUCOSE AND BLOOD LACTATE KINETICS DURING INCREMENTAL RUNNING TEST / 体力科学

Blood lactate kinetics is an important physiological determinant of endurance exercise performance. Recently, some studies reported that the blood glucose transition point can also be observed (blood glucose threshold; GT) and the GT is consistent with the lactate threshold (LT). However, we have recently reported that blood glucose kinetics and blood lactate kinetics were different during two sets of incremental running tests in the same day. This result suggested that influence of low glycogen storage on GT and LT are different. This study was intended to clarify the effect of low glycogen storage on the blood glucose and the blood lactate kinetics during incremental running test performed two successive days. Eight male endurance runners participated in incremental running test performed two successive days. The main finding was that the blood glucose was significantly lower in the second day than the first day during incremental test, although blood glucose was not different at rest in both days. However, blood lactate was not different form rest to fifth stages in both days, significantly lower only at the final stage in the second day than the first day. Respiratory exchange ration were lower in the second day compared to the first day. GT was significantly higher in the second day than the first day, but LT was not different in both days. We concluded that low glycogen storage effected blood glucose kinetics more than blood lactate kinetics, and resulted in only the change of GT.

A Variação do método de incremento de cargas não altera a determinação do limiar de lactato em exercício resistido / Variation in the incremental workload method does not change the lactate threshold determination in resistance exercise

Com o objetivo de analisar e comparar diferentes protocolos incrementais (PI) em exercício resistido para a identificação do limiar de lactato (LL), 12 voluntários homens (23,3 ± 1,6 anos) adaptados ao exercício resistido foram submetidos a dois testes incrementais realizados em leg press 45º (LP). Os PI's foram: 1) relativo ao teste da carga máxima (PI por cento1RM), com incrementos de 19, 28, 32, 37, 41, 45, 55 e 60 por cento de 1RM; 2) relativo ao peso corporal (PI por centoPC), com incrementos de 17, 33, 50, 67, 83, 100, 117 e 133 por cento do PC. Em ambos os PI's a duração de cada estágio foi de 1 min, sendo realizadas 30 repetições em cada. Durante os intervalos entre cada estágio (2 min para o PI por cento1RM e de 1 min para o PI por centoPC) foram coletados do lóbulo da orelha, 25µL de sangue capilarizado, os quais foram depositados em microtúbulos Eppendorff para posterior dosagem das concentrações de lactato sanguíneo [Lac]. Foi possível identificar o LL a partir da resposta das [Lac] nos diferentes protocolos. Não foram observadas diferenças significativas entre o LL determinado por cargas absolutas (PI por cento1RM - 72,3 ± 12,5 vs. PI por centoPC - 65,9 ± 11,5kg; p > 0,05) e relativas (PI por cento1RM - 32,3 ± 4,2 vs. PI por centoPC - 31,6 ± 4,3 por cento; p > 0,05). Alta correlação foi observada entre os PI's, tanto para cargas absolutas (r = 0,90; p < 0,01) como relativas (r = 0,83; p < 0,01). Concluiu-se que, apesar de modificações realizadas nos protocolos adotados, foi possível identificar o LL em LP na amostra estudada, em que as intensidades relativas e absolutas a esses limiares não diferiram e apresentaram correlação entre si. Sugere-se a identificação do LL em exercício resistido através de protocolo com incrementos relativos ao PC, tendo em vista a vantagem de não ser necessário submeter o avaliado à aplicação prévia de um teste de carga máxima.

The aim of this investigation was to analyze and compare different incremental protocols (IP) to identify the lactate threshold (LT) in resistance exercise. 12 male volunteers (23.3 ± 1.6 years) adapted to resistance exercise were submitted to two incremental tests performed in leg-press 45º (LP). The IP were: 1) concerned with the maximum workload test (IP percent1RM), with incremental load corresponding to 19, 28, 32, 37, 41, 45, 55 and 60 percent of 1RM; 2) concerned with the body weight (IP percentBW), with incremental load of 17, 33, 50, 67, 83, 100, 117 and 133 percent of the BW. Both IP had stage duration of 1-min, each with 30 repetitions. During intervals between stages (2-min to IP percent1RM and 1-min to IP percentBW), 25 µL of blood were collected from ear lobe and then placed in Eppendorff microtubes for blood lactate concentration [Lac] dosing. It was possible to identify LT from the responses of the [Lac] in both protocols. No significant differences were observed between the LT intensities determined by absolute (IP percent1RM - 72.3 ± 12.5 vs. IP percentBW - 65.9 ± 11.5 kg; p > 0.05) and relative loads (IP percent1RM - 32.3 ± 4.2 vs. IP percentBW - 31.6 ± 4.3 percent1-RM; p > 0.05). High correlation was observed between the IP percent1RM and IP percentBW both for absolute (r = 0.90; p < 0.01) as well as for relative loads (r = 0.83; p < 0.01). In conclusion, despite protocols modifications during the incremental test on resistance exercise, it was possible to identify the LT in LP in the studies sample in which relative and absolute intensities did not differ from each other and presented high correlation between them. The results suggest that LT in resistance exercise should be identified through a protocol with increments based on the BW percent. Such procedure has the advantage of not submitting the participant to a previous 1 RM incremental test.

Força crítica em nado atado para avaliação da capacidade aeróbia e predição de performances em nado livre / Critical force during tethered swimming for the evaluation of aerobic capacity and prediction of performances in freestyle swimming

The present study investigated the relationship of critical force (Fcrit) with lactate threshold (LLNA) and the intensity corresponding to VO2max (iVO2max) in tethered swimming (TS), and their correlation with maximal performance in 400-m (V400) and 30-min (VT30) freestyle swimming (FS). Seven swimmers were submitted to a TS incremental test for the determination of LLNA and iVO2max. For the determination of Fcrit, the swimmers performed four exercises to exhaustion at intensities (F) corresponding to 87%, 104%, 118% and 134% of iVO2max for the calculation of time limits (Tlim). Fcrit corresponded to the linear coefficient of the ratio between F and 1/tlim. The maximal performance in FS corresponded to the mean velocity obtained during maximal exercise of 400-m and 30-min crawl swimming. Fcrit (51.97 ± 4.02 N) was significantly lower than iVO2max (60.21 ± 8.73 N) but not than LLNA (45.89 ± 8.73). Fcrit was significantly correlated with iVO2max (0.97), LLNA (0.88), V400 (0.85), and VT30 (0.86). These data suggest that Fcrit can be used for the determination of aerobic capacity, prescription of a TS training program, and prediction of performance in FS.

The present study investigated the relationship of critical force (Fcrit) with lactate threshold (LLNA) and the intensity corresponding to VO2max (iVO2max) in tethered swimming (TS), and their correlation with maximal performance in 400-m (V400) and 30-min (VT30) freestyle swimming (FS). Seven swimmers were submitted to a TS incremental test for the determination of LLNA and iVO2max. For the determination of Fcrit, the swimmers performed four exercises to exhaustion at intensities (F) corresponding to 87%, 104%, 118% and 134% of iVO2max for the calculation of time limits (Tlim). Fcrit corresponded to the linear coefficient of the ratio between F and 1/tlim. The maximal performance in FS corresponded to the mean velocity obtained during maximal exercise of 400-m and 30-min crawl swimming. Fcrit (51.97 ± 4.02 N) was significantly lower than iVO2max (60.21 ± 8.73 N) but not than LLNA (45.89 ± 8.73). Fcrit was significantly correlated with iVO2max (0.97), LLNA (0.88), V400 (0.85), and VT30 (0.86). These data suggest that Fcrit can be used for the determination of aerobic capacity, prescription of a TS training program, and prediction of performance in FS.

RELATIONSHIP BETWEEN OPEN-WATER SWIMMING PERFORMANCE AND AEROBIC CAPACITY / 体力科学

The purpose of the present investigation was to examine the relationship between the open water swimming (OW) performance and the swimming speed at 2, 3, and 4 mmol/l of blood lactate concentration (SSLA2, SSLA3, and SSLA4) or the critical swimming speed (CSS). Six male collegiate swimmers performed the 10 kilometers of OW, as well as the multi-stage graded swimming test, in order to determine the SSLA2, SSLA3, SSLA4. Furthermore, the CSS was calculated based on the personal best records for 50 to 1500 meters of free-style indoor swimming. As a result, the SSLA2, SSLA3, SSLA4, and CSS corresponded to 102±6%, 106±6%, 110±7%, and 106±5% of the average swimming speed of the OW, respectively. Thereafter, the SSLA2 did not differ significantly in comparison to the average swimming speed of the OW, whereas the SSLA3, SSLA4, and CSS differed significantly with the average swimming speed of the OW (p＜0.05). Furthermore, the average swimming speed during the OW significantly correlated with the SSLA2, SSLA3, SSLA4, and CSS, respectively (p＜0.05). These results suggest that the OW performance significantly correlated with the swimming speed at 2 to 3 mmol/l of the blood lactate concentrations and CSS. Furthermore, regarding these parameters, the SSLA2 may accurately reflect the average swimming speed of OW.

EVALUATION OF EXERCISE PRESCRIPTION BASED ON THE HEART RATE AND WORK RATE AT THE LACTATE THERSHOLD IN OBESE SUBJECTS WITH AND WITHOUT HYPERTENSION / 体力科学

Prescribed exercise regimens based on the target heart rate (THR) and the target work rate (TWR) on a cycle ergometer at the intensity of the lactate threshold (LT) were evaluated before, and after 6 and 12 weeks of exercise therapy in obese subjects with (OBHT, n=38) and without hypertension (OB, n=55) matching for age, sex, BMI, body composition, as well as the blood glucose, cholesterol and triglyceride level. THR was 97.8±9.2 in OBHT and 98.3±10.7 in OB without group differences. The resting HR was higher in OBHT than in OB (76.3 vs. 72.1). Both the relative THR (%HR reserve) and the relative TWR (%Body weight) were lower in OBHT than in OB. During the training period, the VO₂max, THR and TWR increased while body fat decreased significantly in both groups. The resting BP and HR decreased, and the %HRR increased significantly in OBHT. In conclusion, the lower THR and TWR are therefore recommended when initially prescribing an exercise regimen without an exercise stress test for obese individuals, particularly for the obese subjects with HT based on the exercise intensity at LT. Thereafter, careful modifications in the prescribed exercise regimen will be needed according to improvements in the fitness level and in coronary risk factors.

AEROBIC CAPACITY AND THE METHOD TO EVALUATE IT IN COMMUNITY DWELLING ELDERLY / 体力科学

The purpose of this study is to discuss the effects of aging and exercise on aerobic capacity in the elderly and the procedure for encouraging sedentary elderly to engage in a health promotion program based on aerobic exercise. Regular proper aerobic exercise training, even when started as an elder, induces an increase in maximal oxygen intake and lactate threshold (or ventilatory threshold) by enhancing ventricular diastolic function and oxidative capacity in muscle ; and reduces the risk factors of lifestyle related diseases. There was a need for a simple test for determining aerobic capacity and exercise prescriptions in community-dwelling elderly. We recommended two methods for this purpose : one is to determine DPBP and the other is to estimate work rate at a certain concentration (rest plus 0.1 mmol /l ) of the blood lactate based on it just after 2 A stage step exercise. Both work rate can be used not only for evaluation of the aerobic fitness level, but also a safer and effective exercise intensity to elucidate the benefit of aerobic exercise. These tests were very simple and can determine 5 to 10 people simultaneously.

EFFECT OF COOLING DOWN ON BLOOD LACTATE REMOVAL AND ANAEROBIC WORKOUT IN EXHAUSTIVE CYCLE ERGOMETER EXERCISE / 体力科学

The purpose of this study was to examine the effect of active recovery between two strenuous anaerobic exercises separated by a short time interval. Eight healthy adult male volunteers (age: 24.8±1.8 yrs, height: 170.6±2.5 cm, weight : 70.1 ±2.5 kg) underwent five exercise sessions. Each session consisted of a warm-up, the first anaerobic exercise test (40 sec of exhaustive cycle ergometer exercise), a 30 min inactive (seated) or active recovery period, and a second anaerobic exercise test. During the active recovery period, subjects executed one of four different intensity pedaling tests (60, 80, 100, 120% of predetermined lactate threshold intensity) for 10 min. There were no significant differences in mean power and peak blood lactate concentration among sessions during the first anaerobic exercise test. Significant differences were found in the blood lactate concentration among sessions during the second anaerobic exercise test, and significant differences were found in mean power for the second anaerobic exercise. Optimal intensity related to the blood lactate removal rate was 83.3±7.1%LT, and that related to the working capacity recovery rate was 68.3±11.8%LT.<BR>From these results, concerning blood lactate removal rate, it was suggested that between 80%LT and 100%LT was an effective intensity. As for performance, the effective intensity was less than 100%LT.

APPLICATION OF HEART RATE AT LACTATE THRESHOLD TO KARVONEN'S FORMULA IN CASES OF MULTIPLE RISK FACTORS / 体力科学

Heart rate (HR) corresponding to lactate threshold (LT) was evaluated in patients with multiple risk factors and applied to determine the target HR by Karvonen's formula calculated from the predicted HR max. The subjects were 52 outpatients (33 men and 19 women) aged from 23 to 70 years old (mean 46.9) with more than 2 risk factors including obesity, hypertension, diabetes mellitus, impaired glucose tolerance, dyslipidemia, hyperuricemia, and hyperinsulinemia. A multistage graded test of submaximal exercise on electric bicycle ergometer was performed for each subject before starting exercise therapy. The workload was increased every 4 minutes, and heart rate, blood pressure, and blood lactate concentration were measured during the last 1 minute of each stage. The LTHR ranged from 80 to 120 beats/min (mean 101±10) and Karvonen's coefficients ranged from 0.08 to 0.40 (mean 0.22±0.08) . Because of these differences and variance, it is suggested that LTHR should be measured directly or about 20% HR reserve should be prescribed at least when starting exercise therapy for these cases.

Effects of walking habit on aerobic work capacity and vital age in middle-aged and elderly walkers / 体力科学

The purpose of this investigation was to determine the effects of daily walking on aerobic work capacity, vital age and other fitness components in middle-aged and elderly walkers. The subjects were thirty-six walkers (average 65.0±8.0 yr, 51-80 yr), whose training period averaged 13.5±9.0 yr. The walkers were significantly greater in maximal oxygen uptake (VO<SUB>2</SUB>max), and oxygen uptake at the lactate threshold (VO<SUB>2</SUB>LT), and were 6.5 yr younger in vital age (VA) than sedentary middle-aged and elderly. These findings suggest that middle-aged and elderly walkers have more favorable profile of aerobic work capacity and of health status when compared to sedentary persons.

The effects of long-term low intensity aerobic training and the cessation of training on the serum lipid and lipoprotein concentrations in older patients / 体力科学

The effects of long-term low intensity aerobic training and detraining on serum lipid and lipoprotein concentrations were examined in 10 older patients suffering from hypertension and coronary heart disease. Training was carried out for 30 minutes 3-6 times a week for a mean of 17.1 months using a treadmill with the intensity level set at the blood lactate threshold (LT) .<BR>Following this training both LT and the serum HDL-c increased significantly (P<0.001, P<0.01, respectively) after 6 months while the TC/HDL-c ratio decreased singificantly (P<0.001) only after 1 month and stabilized at a steady favorable value throughout the remainder of the study. The serum TC, TG and LDL-c did not change significantly by the end of the training period. There was a significant negative correlation between the initial TC/ HDL-c level and the change in the TC/HDL-c level at 1 month after training (r=-0.71, P< 0.02) . Only 1 month after the detraining the HDL-c decreased significantly while the TC/HDL-c increased in comparison with the final training value (P<0.001, P<0.05, respectively) and then returned to the pre-training levels.<BR>In conclusion, these results suggest that long-term low intensity aerobic training could improve the profile of the serum lipid and lipoprotein concentrations in older patients. However, these results might depend on such factors as a low HDL-c level, a high TG level, the length of the exercise period, or the frequency per week and the age of the patient, while the cessation of such training quickly returned the profile to that of pre-training levels.

The effects of long-term mild aerobic training at lactate threshold and its cessation on blood pressure in older hypertensive patients under medication / 体力科学

After a general clinical observation period of 3 months, men and women from 66-82 yr. of age with hypertension (n=10) were studied to assess the effects of long-term mild aerobic training and detraining on their blood pressure. Ten patients agreed to take part in aerobic training using a treadmill with the intensity at the lactate threshold (LT) for 30minutes 3-6 times a week for mean 17.1±9.8 months while the time course of changes in the resting blood pressure was monitored.<BR>Following the training period the LT increased significantly by the end of the training period (P<0.001) . After 3months of training both the systolic and diastolic blood pressure decreased significantly (P<0.05, respectively) and both blood pressures stabilized at a significantly lower level throughout the remainder of the study. The mean blood pressure decreased significantly for 9 months (P<0.05) . Finally, the systolic, mean and diastolic blood pressure were found to have decreased significantly, by 9, 5, 11 mmHg, respectively by the end of the training period. (SBP and MBP: P<0.05, DBP: P<0.01, respectively) . One month after the training ended the systolic, mean and diastolic blood pressure all increased significantly (SBP and MBP: P<0.001, DBP: P<0.01, respectively) and approached the initial pre-training levels.<BR>In conclusion, the antihypertensive effect of mild aerobic training at the LT was confirmed for older patients taking antihypertensive medications. However, the cessation of such training resulted in a quick return to pre-training levels.

The effect of different environmental conditions on blood lactate accumulation, LT and OBLA during incremental exercise / 体力科学

The purpose of this study was to compare blood lactate concentration, lactate threshold (LT) and onset of blood lactate accumulation (OBLA) during an incremental bicycle exercise under a hot dry environment with those during the same workload under a thermoneutral environment. Eight unacclimated men performed an incremental test to exhaustion on a cycle ergometer during which the work rate was increased by 30 W every three minutes under thermoneutral (25°C) and hot dry (40°C) environmental conditions. Oxygen consumption (VO<SUB>2</SUB>) -pulmonary ventilation (VE), gas exchange measures and earlobe blood samples for lactate analysis were obtained every minute during the test. LT (p<0.05) and OBLA (p<0.01) occurred at significantly lower VO<SUB>2</SUB> under the hot environment than those under the thermoneutral environment. Additionally blood lactate concentration was significantly higher (p<0.05) at each measurement period under the hot environment compared with that under the ther-moneutral environment. The correlation between LT and ventilatory threshold (VT) was not statistically significant under the thermoneutral (r=0.20) and hot dry (r=0.60) environments, These findings demonstrate that the hot dry environment may increase blood lactate concentration more and causes a leftward shift of LT and OBLA. Since blood lactate accumulation during incremental exercise is not considered to be the only factor which mediates VE, VT does not always accurately predict LT.

Effects of 9 months mild aerobic training on serum lipids and lipoprotein concentrations in older than 65 years men and women with hypertension / 体力科学

In the present study, we instiuted a long-term mild aerobic training program for older patients with hypertension and investigated its effects on serum lipids and lipoprotein concentrations. The intensity of exercise in mild aerobic training was adjusted to the lactate threshold level (LT), i, e., the level at which the blood lactate concentration began to increase nonlinearly with increasing work intensity. The training group (15 patients, 7 men and 8 women) and control group (15 patients, 7 men and 8 women) were 65-83 year-old patients with mean ages of 75.5±5.6 and 73.7±4.4 (mean±S.D), respectively, who had never exercised regularly up to that time. Treadmill training at the LT was carried out for 30min/day 3-6 times/week and continued for 9 months under the supervision of exercise physiology specialists.<BR>In the training group, LT speed significantly increased from 3.43±0.65 km/h to 3.73±0.67 km/h (9.0%) in men, and from 2.75±0.57 km/h to 3.05±0.61 km/h (11.8%) in women (both P<0.05) . HDL-c was significantly increased 9 months after training both in men (19.2%) and women (20.9%) (both P<0.05) . The TC/HDL-c ratio, an atherogenetic index, was significantly (P<0.05) decreased by training in women but not in men. The other serum lipid and lipoprotein profiles were unchanged in both men and women. In the control group, all serum lipid and lipoprotein profiles were unchanged in both men and women.<BR>The HDL-c level in the training group was higher than in the control group after 9 months in both men and women (both P<0.02) . The TC/HDL-c ratio in the training group was lower only in women (P<0.02) . There were no significant differences in other values between the training group and the control group in either men or women.<BR>These results suggest that mild aerobic training at the LT is an effective method of improving the level of serum HDL-c, the TC/HDL-c ratio and aerobic capacity in the older patients with hypertension.

Maximal oxygen uptake and lactate threshold in middle-aged and older runners - With special reference to aging / 体力科学

Maximal oxygen uptake (Vo<SUB>2</SUB>max) and lactate threshold were measured during an incremental bicycle ergometer test in 40 healthy middle-aged and older runners between 43 and 79 years of age. Although the 10-km run time slowed with increasing age, there were no significant differences in recent training habits or relative amount of body fat between four age groups. However, our cross-sectional data revealed an annual decrement of -0.74 m<I>l</I>/kg/ min/yr, which was significantly greater than that reported in previous studies. Vo<SUB>2</SUB>max values for the runners were greater than those for sedentary men of similar ages by about 50% in each age group. Significant correlations were found between the age at the onset of running training and Vo<SUB>2</SUB>max (r=-0.600, p<0.05) . Vo<SUB>2</SUB>@LT declined significantly but less rapidly with age (r=0.686, p<0.05) than Vo<SUB>2</SUB>max. Both the mean maximal heart rate (HRmax) and HR@LT also declined with age. No significant differences in HRmax were observed between the runners and sedentary men of the respective age groups. Significant correlations were also found between the estimated HRmax and directly measured HRmax (r=0.600) . Neither systolic blood pressure nor diastolic blood pressure during submaximal-maximal exercise were found to increase with age. We suggest that maintenance of a higher lactate threshold in older runners when expressed as a percentage of Vo<SUB>2</SUB>max is attributable to a greater age-dependent decline in Vo<SUB>2</SUB>max with a smaller change in Vo<SUB>2</SUB>@LT.