Use of sports tourism to motivate older adults to maintain increased aerobic exercise capacity and reduced arterial stiffness after supervised training: a non-randomized controlled trial / 体力科学

Habitual aerobic exercise decreases arterial stiffness, a risk factor for cardiovascular disease, and increases aerobic exercise capacity. Exercise habits can be difficult to maintain over time. We sought to determine if the prospect of participating in a sports tourism event (mountain climbing) helped older adults maintain increased aerobic exercise capacity and decreased arterial stiffness after a supervised training program. Forty community-dwelling middle-aged and older individuals were divided into training (n=20) and control (n=20) groups. The training group participated in six weeks of face-to-face exercise intervention (walking, 60%–75% of age-predicted maximal heart rate, 35–50 min/day, 1 day/week) and was additionally offered home-based walking (45 min/day, 2–4 days/week). During the same period, the control group was asked not to change their lifestyle. In the last session of the exercise program, we announced a mountain climbing event planned for six months in the future. The participants were encouraged to maintain their exercise habits leading up to the event. Arterial stiffness (brachial-ankle pulse wave velocity) and maximal oxygen uptake were measured before and after the six-week intervention and two weeks before the mountain climbing event. In the training group, arterial stiffness decreased, and maximal oxygen uptake increased after the intervention; these improvements were successfully maintained until the mountain climbing event. These parameters did not change significantly in the control group. Sports tourism may motivate older adults to maintain their exercise habits after a supervised training program.

Effects of pre-exercise ingestion of different amounts of carbohydrate at three hours after feeding breakfast on exercise-induced hypoglycemia / 体力科学

The purpose of this study was to compare effects of different amounts of carbohydrate (CHO) in beverage on plasma glucose (GLU) concentration during exercise after feeding breakfast. Seven healthy Japanese male subjects performed 30-min cycling at an intensity on the 75% of maximal load at 3-h after feeding breakfast under 3 types of CHO (0 g, 30 g and 150 g) beverage conditions. The subjects ingested 500 mL of beverage dissolved each amount of glucose at 30-min before the exercise. The GLU concentrations were measured at 35- and 10-min before the exercise and every 5-min during the exercise. The minimum GLU concentrations under the 30 g condition for all subjects were lower than a criterion for hypoglycemic (72 mg / dL). The mean value also fell below the criterion at from 10- to 20-min during exercise. The minimum GLU concentration under the 150 g condition of only one subject was lower than the criterion, but the mean value did not fall below the criterion. Significant negative correlations were found between the subjects’ maximum oxygen uptake (VO2max) and the decreases in GLU concentration from maximum to minimum under both the 30 g (r = -0.947, p < 0.01) and 150 g conditions (r = -0.884, p < 0.01). This study clarified that feeding breakfast at 3-h before the exercise followed by the 30 g CHO beverage ingestion at 30 min before the exercise induced exercise-induced hypoglycemia, and that the subjects with higher VO2max had the greater decreases in GLU concentration.

Caracterización de la capacidad física en niños del Programa Nacional de Fibrosis Quística de Chile / Characterization of the physical capacity in children of the Chilean National Program of Cystic Fibrosis

Resumen: Introducción: La fibrosis quística (FQ) es una enfermedad multisistémica hereditaria y progresiva. Una mejor capacidad física puede retardar la progresión de la enfermedad, mejorando así el pronós tico y la supervivencia. El objetivo de esta investigación fue evaluar la capacidad física de los niños admitidos en el programa nacional de FQ de la Región Metropolitana, Chile. Pacientes y Método: Se utilizó un diseño de estudio transversal multicéntrico. Los criterios de inclusión fueron: niños de 6 a 12 años de edad, incluidos en el Programa Nacional de FQ, madurez sexual Tanner I, ausencia de exacerbaciones respiratorias en los últimos 30 días y ausencia de enfermedades musculoesqueléticas. La capacidad aeróbica máxima fue evaluada a través del consumo pico de oxígeno (VO2pico) y se determinó con un protocolo incremental en un cicloergómetro magnético conectado a un ergoespirómetro en el que paralelamente se analizaron los gases respiratorios: valores de consumo de oxí geno y producción de dióxido de carbono cada 30 segundos, umbral anaeróbico y carga máxima de trabajo. Además, se evaluaron los valores de capacidad vital forzada (CVF), volumen espiratorio al primer segundo (VEFj), relación VEFj/CVF y los flujos espiratorios forzados entre el 25 y 75% de la capacidad vital. Durante la prueba se registró: saturación arterial de oxígeno, frecuencia respiratoria, frecuencia cardíaca, presión arterial, volumen corriente y se consultó la percepción de fatiga de extre midades inferiores y disnea a través de la escala de Borg modificada. La duración aproximada del test fue alrededor de 10 minutos. Resultados: Se revisaron los registros clínicos de 43 niños, recogidos en seis centros de salud. Veintinueve niños cumplieron los criterios de inclusión siendo 23 reclutados. Dos niños no pudieron participar, reduciendo el grupo final de sujetos a 21 (13:8 varones:mujeres). La edad media fue de 8,8 ± 2 años; el peso fue de 30,5 ± 10,9 kg; la talla fue de 1,32 ± 0,11 m y el índice de masa corporal fue de 17,1 ± 3,5 (z-score 0,01 ± 1,34). Más de la mitad (61%) de los niños estaba eutrófico. El VO2pico obtenido fue de 43,7 ± 6,5 ml/min/kg (106,7 ± 19,8% de los valores teóricos de referencia). Sólo el 10% de los niños tenían valores inferiores a los valores teóricos esperados para población normal, ajustados por sexo y edad. No se encontraron correlaciones entre el VO2pico y las variables antropométricas y de función pulmonar. Conclusión: La mayoría de los niños evaluados (90%) tenían capacidad física similar a los valores teóricos de referencia para niños sanos ajustados por sexo y edad.

Abstract: Introduction: Cystic fibrosis (CF) is an inherited, progressive, multisystem disease. Better physical capacity may slow disease progression, thus improving prognosis and survival. The objective of this research was to evaluate the physical capacity of children admitted to the National CF Pro gram of the Metropolitan Region, Chile. Patients and Method: A multicenter, cross-sectional stu dy design was used. The inclusion criteria were children aged 6 to 12 years enrolled in the National CF Program; Tanner sexual maturity stage I, no respiratory exacerbations in the last 30 days, and no musculoskeletal pathologies. The maximum aerobic capacity was assessed through the peak oxygen uptake (VO2peak) and determined with an incremental protocol in a magnetic cycle ergometer connected to an ergo-spirometer with which, at the same time, respiratory gases, oxygen consumption and carbon dioxide production values every 30 seconds, anaerobic threshold, and maximum workload were analyzed. The values of forced vital capacity (FVC), forced expiratory volume in 1 second (FEVj), FEVj/FVC ratio, and forced expiratory flows between 25% and 75% of vital capacity were assessed through ergo-spirometry. At the beginning of the ergo-spirometry, arterial oxygen saturation, respiratory rate, heart rate, blood pressure, tidal volume and the per ception of lower extremity fatigue and dyspnea were recorded using the modified Borg scale. The test lasted approximately 10 minutes. Results: The clinical records of 43 children collected from six health centers were reviewed. Out of these, 29 children met inclusion criteria, and 23 were re cruited. Two children were unable to participate, reducing the final subject group to 21 (13 males, 8 females). The mean age was 8.8 ± 2 years; weight 30.5 ± 10.9 kg; height 1.32 ± 0.11 m; and body mass index 17.1 ± 3.5 (z-score 0.01 ± 1.34). More than half of the children (61%) had normal weight. The obtained VO2peak was 43.7 ± 6.5 ml/min/kg (106.7 ± 19.8% of the predictive values). Only 10% of the children had values lower than those predicted by sex and age. No correlations were found between VO2peak and anthropometric and pulmonary function variables. Conclu sion: Most of the evaluated children (90%) had physical capacity similar to healthy subjects by sex and age.

A comparison of aerobic capacity in long-distance runners and triathletes with the same level of running performance / 体力科学

The purpose of this study was to clarify the aerobic fitness of triathletes comparing with long-distance runners with the same level of running performance. Thirteen male university endurance athletes were divided into two groups ; long-distance runners and triathletes. The subjects performed maximal and submaximal treadmill running test to assess their maximal oxygen uptake (VO2max) and running economy (RE). The VO2max (ml/kg/min) in triathletes was lower than that in the runners (p = 0.08, d = 1.18). The RE (ml/kg/km) in triathletes was higher than that in the runners (p = 0.05, d = 1.34). This study suggests that the difference of aerobic fitness between two homogeneous groups is caused by running form and the training with preceding exercise.

Futsal improve body composition and cardiorespiratory fitness in overweight and obese children. A pilot study

The aim of this study was to verify body composition, cardiorespiratory fitness, and biochemical markers of prepubertal overweight and obese boys to a 16-week futsal training program. Methods: Sixteen boys (age: 7-10 y, body mass index>thanat 95th percentileaccording to Center for Disease Control and Prevention; 35.5±7.4 percent fat) participated to futsal training program. The assessment of body composition was estimated using skinfold thickness, and the following variables were evaluated: total body mass, body mass index, body fat percentage, and lean body mass. Aerobic fitness measurementwas performed by gas exchange analysis in treadmill. In addition, an evaluation of the biochemical profile was conducted: triglycerides, total cholesterol, low density lipoprotein cholesterol, high-density lipoprotein cholesterol, plasma concentrations of glucose, and insulin. The futsal intervention included 60-min sessions performed two times/week. The mean intensity during training was between 57 to 88% of maximal heart rate of the age-predicted. Individual portable heart rate monitor controlled training intensity. Results: Significant increases in total body mass (4%), height (3%), lean body mass (8%), and significant 6%-decrease in body fat percentage was observed. Body mass index remained unchanged. Maximal oxygen uptake was elevated (p<0.018) by 11%. Biochemical markers were not modified after intervention. No association was found between body composition and metabolic variables. The effect size of futsal training on most variables was small (<0.5). Conclusion: Controlled intensity and adherence to this 16-week futsal training program were determinant to enhance body composition, and cardiorespiratory fitness in this group of prepubertal boys.(AU)

Running economy in elite soccer and futsal players: differences among positions on the field / Economia de corrida em jogadores de futebol e futsal de elite: diferenças entre as posições em campo

OBJECTIVE: To determine running economy in a large sample of elite soccer and futsal players to obtain benchmarks in different positions. METHODS: Running Economy is the energy demand at a submaximal running velocity. Players were divided into 6 subgroups. Soccer: defenders, midfielders, and strikers; futsal: defenders, wingers, and pivots. Elite soccer players (n=129) and elite futsal players n=72 performed an incremental running test starting at 8.4 km.h-1 with increments of 1.2 km.h-1 every two minutes on a treadmill until exhaustion. Running Economy was determined by interpolation between ventilatory thresholds 1 and 2 (VT1 and VT2). RESULTS: Running Economy (measured as mL.kg-1.km-1) was compared between the playing positions in the two team sports. In soccer, running economy was 222.7 (defenders), 227.0 (midfielders), and 219.8 (strikers) mL.kg-1.km-1, respectively. In futsal, the corresponding values were 198.5 (defenders), 196.9 (wingers), and 190.5 (pivots) mL.kg-1.km-1, respectively. We no found significantly differences between the three positions in both sports. The Running Economy of futsal players was 12.5% better than that of soccer players. Running Economy correlated positively with oxygen uptake at VT2 in both sports and in all positions. CONCLUSION: Futsal players exhibited better Running Economy than soccer players; this should be considered as a factor in the athlete's training plan.

OBJETIVO: Determinar a Economia de Corrida numa grande amostra de jogadores de futebol e futsal de elite em diferentes posições do campo. METODOS: Os jogadores foram subdivididos em três subgrupos: futebol (jogadores de defesa, meio-campistas e atacantes) e futsal (jogadores de defesa, alas e pivôs). Foram 129 jogadores de futebol e 72 jogadores de futsal, que competem nas respectivas primeiras divisões do Brasil. Os jogadores foram submetidos a teste de esforço em esteira (8,4 km-1.h+1,2km-1.h a cada dois minutos) até a exaustão. Consumo máximo de oxigênio, limiares ventilatórios e Economia de Corrida foram registrados por análise de troca gasosa respiratória. A Economia de Corrida foi determinada por interpolação utilizando as velocidades dos limiares ventilatórios 1 e 2 e o consume de oxigênio nas duas velocidades. RESULTADOS: Os valores de Economia de Corrida entre as posições nos dois esportes foram os seguintes: Futebol, jogadores de defesa (222,7±16,7mL.kg-1.km-1), meio-campistas (227±19,9mL.kg-1.km-1), e atacantes (219,8±17,2mL.kg-1.km-1). Futsal, jogadores de defesa (198,5±10,8mL.kg-1.km-1), alas (196,9±16,2mL.kg-1.km-1), e pivôs (190,5±11,8mL.kg-1.km-1). Não foram encontradas diferenças significativas entre as três posições em ambos os esportes. A Economia de Corrida dos jogadores de futsal foi 12,5% melhor do que dos jogadores de futebol. Neste estudo, os jogadores da posição pivô no futsal tiveram os melhores valores de Economia de Corrida (custo de oxigênio mais baixo). Embora o consumo máximo de oxigênio (VO2max) e o limiar ventilatório 2 (LV2) fosse maior nos jogadores de futebol, a Economia de Consumo foi pior. Esta correlacionou-se positivamente com o VO2 no LV2 em ambos os esportes e em todas as posições CONCLUSÃO: Futsal tem melhor Economia de Consumo do que futebol. O presente estudo aponta a importância dos índices Economia de Consumo no plano de treinamento físico dos atletas.

Walking economy and aerobic power in Parkinson's disease after endurance exercise training: A pilot study / Economia de caminhada e potência aeróbia na doença de parkinson após programa de treinamento de endurance: um estudo piloto

OBJECTIVE: To verify the effect of an endurance exercise program in middle stages of Parkinson's disease. METHODS: The patients were two women and seven men with Parkinson's disease, aged 56 to 74 years, classified at Hoehn and Yahr stages 2 to 2.5. The study was designed as an open long-term pilot trial over three months of supervised treadmill exercise training. Cardiopulmonary exercise test evaluations were performed before the start of the study (test 1) and after three months (test 2). The main outcome measure was walking economy (i.e., the rate of oxygen consumption during gait) measured between VT1 and VT2 speeds and Oxygen consumption (VO2). RESULTS: No changes (p=0.551) were observed for maximal oxygen uptake (VO2max, 24.6 vs 23.6 mL.kg-1.min-1) between tests. The walking economy was 20% better (p<0.001) after three months of aerobic endurance training (266.7 vs 212.6 mL.kg-1.km-1, pre- vs. post-training); the Cohen's "d" effect size (ES) was 0.99, a very large effect. CONCLUSION: Evidence from this pilot study in individuals with Parkinson's disease suggests that gains in walking economy occurs with a treadmill-training program without gain in aerobic power, but which may positively reduce the energy expenditure of activities of daily living in these patients.

OBJETIVO: Verificar o efeito de um programa de treinamento físico aeróbio em estágios intermediários da doença de Parkinson (PD). MÉTODOS: Os pacientes eram duas mulheres e sete homens com PD, com idade entre 56 e 74 anos, classificados como estágios Hoehn e Yahr 2 a 2,5. O estudo foi concebido como um ensaio piloto aberto de longo prazo durante três meses de treinamento supervisionado e realizado em esteira ergométrica. As avaliações da troca gasosa pelo teste de exercício cardiopulmonar foram realizadas antes do início do estudo (teste 1) e após três meses (teste 2). A determinação da economia de caminhada (taxa de consumo de oxigênio durante a marcha) foi medida entre as velocidades do primeiro e do segundo limiar (LV1 e LV2) e do consumo de oxigênio (VO2) entre as duas velocidades por interpolação. RESULTADOS: Não foram observadas alterações (P = 0,153) para o consumo máximo de oxigênio (VO2max: 26,7 vs. 24,2 mL.kg-1.min-1) após o período de intervenção. A economia de caminhada foi 23% maior (P <0,001) após três meses de treinamento físico aeróbio (273,4 vs. 209,4 mL.kg-1.km-1, ES = 0.99, muito alto). CONCLUSÃO: Evidências deste estudo piloto em indivíduos com DP sugerem que os ganhos na economia de caminhada podem ocorrer com um programa de treinamento de "endurance" aeróbica na esteira sem ganho na potência aeróbia, mas que positivamente pode reduzir o gasto de energia das atividades da vida diária nesses pacientes.

Cinética de la inmunoglobulina-A salival (IgAs) en adultos jóvenes con capacidad aeróbica promedio o excelente antes y después de una prueba de esfuerzo máximo / Salivary immunoglobulin A (sIgA) kinetics in young adults with an average or excellent aerobic capacity before and after a cardiopulmonary graded exercise test

Background: Aim: To compare the concentration of secretory immunoglobulin-A (sIgA) in young adults with average or excellent aerobic capacity before and after a cardiopulmonary graded exercise test. Methods: Participants were nine apparently healthy physically active males (Mean age = 21.3 ± 2.1 yr.), randomly allocated in two groups based on their VO2max: a) average aerobic capacity (AEC, n = 5) or b) excellent aerobic capacity (EAC, n = 4). Participants performed the Bruce protocol to determine their aerobic capacity. The sIgA was measured before the test, immediately after the test and 60-, 120-, 240-, and 1440-min after the test. Results: Mixed factorial 2 x 6 ANOVA indicated no significant interactions between groups and measurements (p = 0.956), and main effect groups on sIgA (AEC = 85.4 ± 19.3 μg/mL vs. EAC = 79.2 ± 21.5 μg/mL, p = 0.836). Tukey's post hoc analysis revealed significant differences measurement obtained immediately after the test and between the initial measurement (p = 0.020), 60-min (p = 0.030), 240-min (p = 0.016), and 1440-min (p = 0.028) following the test. Conclusion: There is no change in sIgA kinetics depending on the aerobic capacity of the participants following an aerobic capacity cardiopulmonary graded exercise test.

Introducción. Objetivo: Comparar la cinética en la concentración de inmunoglobulina A salival (IgAs) en adultos jóvenes con capacidad aeróbica promedio (n: 5) o excelente (n: 4) antes y después de una prueba de esfuerzo. Método: 9 adultos jóvenes (edad 21,3 ± 2,1), divididos de acuerdo su VO2máx, realizaron una prueba de esfuerzo mediante el protocolo de Bruce. La concentración de IgAs fue determinada mediante el Salimetrics IgA Kit®, evaluando inicial, inmediatamente finalizada la prueba, +60, +120, +240, +1.440 min. Resultados: La prueba ANOVA 2x6 mixta indicó que no existieron interacciones significativas entre grupos y mediciones (p = 0,956). Tampoco se encontró una diferencia significativa en la media de IgAs en los grupos (Promedio = 85,4 ± 19.3 μg/mL vs Excelente=79,2 ± 21.5 μg/mL, p = 0,836). Independientemente de las mediciones, el análisis post hoc de Tukey indicó que las diferencias se encontraron en la medición obtenida inmediatamente después de la prueba y entre la medición inicial (p: 0,020), la medición obtenida 60 min (p: 0,030), 240 min (p: 0,016) y 1.440 min (p = 0,028) posteriores a la prueba. Conclusión: Los datos encontrados sugieren que no hay un cambio en la concentración de IgAs a través del tiempo en función de la capacidad aeróbica de los participantes.

Effects of a 4-week high-intensity interval training on pacing during 5-km running trial

This study analyzed the influence of a 4-week high-intensity interval training on the pacing strategy adopted by runners during a 5-km running trial. Sixteen male recreational long-distance runners were randomly assigned to a control group (CON, n=8) or a high-intensity interval training group (HIIT, n=8). The HIIT group performed high-intensity interval-training twice per week, while the CON group maintained their regular training program. Before and after the training period, the runners performed an incremental exercise test to exhaustion to measure the onset of blood lactate accumulation, maximal oxygen uptake (VO2max), and peak treadmill speed (PTS). A submaximal constant-speed test to measure the running economy (RE) and a 5-km running trial on an outdoor track to establish pacing strategy and performance were also done. During the 5-km running trial, the rating of perceived exertion (RPE) and time to cover the 5-km trial (T5) were registered. After the training period, there were significant improvements in the HIIT group of ∼7 and 5% for RE (P=0.012) and PTS (P=0.019), respectively. There was no significant difference between the groups for VO2max (P=0.495) or onset of blood lactate accumulation (P=0.101). No difference was found in the parameters measured during the 5-km trial before the training period between HIIT and CON (P>0.05). These findings suggest that 4 weeks of HIIT can improve some traditional physiological variables related to endurance performance (RE and PTS), but it does not alter the perception of effort, pacing strategy, or overall performance during a 5-km running trial.

Exercise and non-exercise aerobic power prediction models using six-minute walk test / Equações de predição da potência aeróbica usando o teste de caminhada de seis minutos

BACKGROUND AND OBJECTIVE: A simple, low-cost approach commonly used to objectively analyze the cardiorespiratory fitness of individuals with different health conditions is the six-minute walk test (6-MWT). Our objective was to develop peak aerobic power prediction using the six-minute walk test in healthy older men. METHODS: We measured body composition (body mass [BM], body mass index [BMI], fat percentage [FAT]) and peak aerobic power breath-by-breath during cardiopulmonary exercise testing (CPET [velocity, heart rate [HR] and VO2 at the anaerobic threshold and peak]) and a 6-MWT (distance [D], weight by distance [WxD], HR and oxygen consumption [VO2] at peak) in 76 healthy older men aged 65 to 80 years (69.1 ± 0.3 yrs-old). RESULTS: We observed significant correlations for VO2peak during the 6-MWT as a function of WxD (R = 0.75, P < 0.0005), BM (R = 0.56, P < 0.0005), D (R = 0.43, P = 0.0004) and maximum HR (R = 0.37, P = 0.001). Distance correlated significantly with FAT (R = -0.43, P = 0.005), BMI (R = -0.36, P = 0.021) and age (R = -0.31, P < 0.045), whereas WxD correlated with BM (R = 0.86, P<0.005).The inclusion of WxD increased the R2 from 0.65 to 0.74 and decreased the estimative error while yielding the following equation (R = 0.86, standard error of the estimate (SEE) = 182.1 mL•min-1, P < 0.0005) to predict VO2peak: VO2peak = 962.2 + (0.037 x WxD) + (8.565 x maximum HR). A non-exercise model was obtained by univariate regressions but not multiple regressions. The FAT (R = 0.43, SEE = 702.2 m, P < 0.005) yielded the best model for predicting distance, i.e., distance = 702.2 - (3.067 x FAT). CONCLUSION: Our prediction model seems to accurately estimate VO2peak in healthy older men primarily when WxD is considered.

OBJETIVO: O teste de caminhada de seis minutos (TC6M) é uma estrategia simples e de baixo custo operacional que objetivamente mede a aptidão cardiorrespiratória de indivíduos com diferentes condições de saúde. Nosso objetivo foi desenvolver equações de predição da potência aeróbica em homens idosos saudáveis usando o TC6M. MÉTODOS: Foram medidos a composição corporal (massa corporal [MC], índice de massa corporal [BMI], porcentagem de gordura [%G]) e potência aeróbica de pico através de teste cardiopulmonar de exercício máximo (velocidade, frequência cardíaca [FC] e consumo de oxigênio [VO2] no limiar anaeróbico e no pico]) e através do TC6M (distancia [D], produto massa corporal x distância, FC e VO2de pico) em 76 idosos saudáveis com idade entre 65 e 80 anos (69.1 ± 0.3 anos). RESULTADOS: Foram observadas correlações significativas para VO2pico no TC6M em função do produto MCxD (R = 0,75, P < 0,0005), MC (R = 0,56, P < 0,0005), D (R = 0,43, P = 0,0004) e FC máxima (R = 0,37, P = 0,001). A correlacionou-se significativamente com %G (R = -0,43, P = 0,005), IMC (R = -0,36, P = 0,021) e idade (R = -0,31, P < 0,045), enquanto que a MCxD correlacionou-se com MC (R = 0,86, P < 0,005). A inclusão da MCxD aumentou o R 2 de 0,65 para 0,74 e diminuiu o erro padrão da estimativa (EPE) gerando a equação (R = 0,86, EPE = 182,1 mL·min-1, P < 0,0005) para a predição do VO2peak: VO2peak = 962,2 + (0,037 x MCxD) + (8,565 x FC máxima). Foi também gerado um modelo preditivo não dependente de exercício através de regressão univariada, mas não múltipla. A %G (R=0,43, EPE = 702,2 m, P < 0,005) gerou o melhor modelo para a predição da distancia, i.e., distancia = 702,2 - (3,067 x %G). CONCLUSÃO: Nossas modelos de predição parecem estimar precisamente o VO2pico de idosos saudáveis, especialmente quando a MCxD é considerada.

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.

Evaluation of energy expenditure in forward and backward movements performed by soccer referees

The aim of this study was to measure the energy expenditure for locomotor activities usually performed by soccer referees during a match (walking, jogging, and running) under laboratory conditions, and to compare forward with backward movements. The sample was composed by 10 male soccer referees, age 29±7.8 years, body mass 77.5±6.2 kg, stature 1.78±0.07 m and professional experience of 7.33±4.92 years. Referees were evaluated on two separate occasions. On the first day, maximal oxygen uptake (VO2max) was determined by a maximal treadmill test, and on the second day, the oxygen consumption was determined in different speeds of forward and backward movements. The mean VO2max was 41.20±3.60 mL·kg-1·min-1 and the mean heart rate achieved in the last stage of the test was 190.5±7.9 bpm. When results of forward and backward movements were compared at 1.62 m/s (walking speed), we found significant differences in VO2, in metabolic equivalents, and in kcal. However, the same parameters in forward and backward movements at jogging velocities (2.46 m/s) were not significantly different, showing that these motor activities have similar intensity. Backward movements at velocities equivalent to walking and jogging are moderate-intensity activities, with energy expenditure less than 9 kcal. Energy expenditure was overestimated by at least 35% when calculated by mathematical equations. In summary, we observed that backward movements are not high-intensity activities as has been commonly reported, and when calculated using equations available in the literature, energy expenditure was overestimated compared to the values obtained by indirect calorimetry.

Energy system contribution in a maximal incremental test: correlations with pacing and overall performance in a 10-km running trial

This study aimed to verify the association between the contribution of energy systems during an incremental exercise test (IET), pacing, and performance during a 10-km running time trial. Thirteen male recreational runners completed an incremental exercise test on a treadmill to determine the respiratory compensation point (RCP), maximal oxygen uptake (V˙O2max), peak treadmill speed (PTS), and energy systems contribution; and a 10-km running time trial (T10-km) to determine endurance performance. The fractions of the aerobic (WAER) and glycolytic (WGLYCOL) contributions were calculated for each stage based on the oxygen uptake and the oxygen energy equivalents derived by blood lactate accumulation, respectively. Total metabolic demand (WTOTAL) was the sum of these two energy systems. Endurance performance during the T10-km was moderately correlated with RCP, V˙O2maxand PTS (P<@0.05), and moderate-to-highly correlated with WAER, WGLYCOL, and WTOTAL (P<0.05). In addition, WAER, WGLYCOL, and WTOTAL were also significantly correlated with running speed in the middle (P<0.01) and final (P<0.01) sections of the T10-km. These findings suggest that the assessment of energy contribution during IET is potentially useful as an alternative variable in the evaluation of endurance runners, especially because of its relationship with specific parts of a long-distance race.

Maximal Fat Oxidation Rate during Exercise in Korean Women with Type 2 Diabetes Mellitus

BACKGROUND: The purpose of this study was to determine the appropriate exercise intensity associated with maximum fat oxidation, improvement of body composition, and metabolic status in Korean women with type 2 diabetes mellitus (T2DM). METHODS: The study included a T2DM group (12 women) and a control group (12 women). The groups were matched in age and body mass index. The subjects performed a graded exercise test on a cycle ergometer to measure their maximal fat oxidation (Fatmax). We also measured their body composition, metabolic profiles, and mitochondrial DNA (mtDNA). RESULTS: The exercise intensity for Fatmax was significantly lower in the T2DM group (34.19% maximal oxygen uptake [VO2 max]) than the control group (51.80% VO2 max). Additionally, the rate of fat oxidation during exercise (P<0.05) and mtDNA (P<0.05) were significantly lower in the T2DM group than the control group. The VO2 max level (P<0.001) and the insulin level (P<0.05) were positively correlated with the rate of fat oxidation. CONCLUSION: The results of this study suggest lower exercise intensity that achieves Fatmax is recommended for improving fat oxidation and enhancing fitness levels in Korean women with T2DM. Our data could be useful when considering an exercise regimen to improve health and fitness.

Stability of relative oxygen pulse curve during repeated maximal cardiopulmonary testing in professional soccer players

During cardiopulmonary exercise testing (CPET), stroke volume can be indirectly assessed by O2 pulse profile. However, for a valid interpretation, the stability of this variable over time should be known. The objective was to analyze the stability of the O2 pulse curve relative to body mass in elite athletes. VO2, heart rate (HR), and relative O2 pulse were compared at every 10 percent of the running time in two maximal CPETs, from 2005 to 2010, of 49 soccer players. Maximal values of VO2 (63.4 ± 0.9 vs 63.5 ± 0.9 mL O2•kg-1•min-1), HR (190 ± 1 vs188 ± 1 bpm) and relative O2 pulse (32.9 ± 0.6 vs 32.6 ± 0.6 mL O2•beat-1•kg-1) were similar for the two CPETs (P > 0.05), while the final treadmill velocity increased from 18.5 ± 0.9 to 18.9 ± 1.0 km/h (P < 0.01). Relative O2 pulse increased linearly and similarly in both evaluations (r² = 0.64 and 0.63) up to 90 percent of the running time. Between 90 and 100 percent of the running time, the values were less stable, with up to 50 percent of the players showing a tendency to a plateau in the relative O2 pulse. In young healthy men in good to excellent aerobic condition, the morphology of the relative O2 pulse curve is consistent up to close to the peak effort for a CPET repeated within a 1-year period. No increase in relative O2pulse at peak effort could represent a physiologic stroke volume limitation in these athletes.

MAXIMAL OXYGEN UPTAKE OF PERSONS WHO HAVE NO HABITUAL EXERCISE / 体力科学

Generally, a person who has higher cardiorespiratory fitness has lower lifestyle-related disease(LRD)morbidity rates and lower mortality rates. In Japan, Ministry of health, labor and welfare has defined the reference values of the maximal oxygen uptake(VO₂max)for health promotion by gender and age in 2006. The reference values were defined based on the systematic review of the japanese and foreign articles for the relationship between VO₂max and LRD. However, the articles based on japanese subjects were few. The purpose of this study is to examine the morbidity rates of LRD and VO₂max of japanese persons who have no habitual exercise. The subjects of this study comprise 141 males and 287 females aged from 20 to 69. The LRD morbidity rates of males and females suffered from dyslipidemia, hypertention, diabetes / impaired glucose tolerance were 78.7% and 58.5%, respectively. The mean VO₂max obtained by an incremental bicycle exercise at all group divided by gender and age did not achieve the reference values. The rate of the LRD subjects of males and females who achieved the reference values were 9.9%(n=11)and 4.8%(n=8), respectively. And the rate of the non-LRD subjects of males and females who achieved the reference values were 36.7%(n=11) and 14.3%(n=17), respectively. To obtain the habitual exercise and to keep higher physical activity is important to control a decline of VO₂max with aging and to prevent the LRD.

É possível determinar a economia de corrida através do teste progressivo até a exaustão? / Is possible to predict running economy using maximal incremental exercise test?

O objetivo do presente estudo foi verificar a possibilidade de se estimar a economia de corrida (EC) a partir do coeficiente angular gerado pela relação VO2 vs. intensidade de testes progressivos até a exaustão (EC INCLINA). Para tanto, 16 corredores de provas de longa duração (idade 32 ± 7 anos, massa corporal 70,0 ± 6,7 kg, estatura 173,3 ± 5,0 cm, O2máx 57,9 ± 5,8 ml·kg-1·min-1) foram submetidos a um teste incremental e a dois testes de cargas constantes (12 km·h-1 e a intensidade de 90 por cento do segundo limiar ventilatório) para a mensuração da EC. Foram detectadas correlações fracas entre o EC INCLINA e a EC estabelecida a 12 km·h-1 (r = 0,49; p = 0,054) e na intensidade de 90 por cento do segundo limiar ventilatório (r = 0,55; p = 0,027). Além disso, o EC INCLINA também estava negativamente correlacionado com a concentração sanguínea de lactato (r = -0,75; p = 0,001) e a razão de troca respiratória (r = -0,80; p < 0,001) mensuradas ao final no teste progressivo. Portanto, esses achados sugerem que, embora a sua aplicação para determinar a EC seja limitada, o EC INCLINA pode ser um parâmetro alternativo empregado para o diagnóstico da aptidão de corredores de provas de longa duração devido a sua relação com o metabolismo anaeróbio.

The purpose of the present study was to investigate the association between running economy (RE) and the slope of the regression line obtained as the individual relationship between oxygen uptake and the corresponding intensity in the incremental test (EC INCLINA). Sixteen recreational long-distance runners (age 32 ± 7 years, body mass 70,0 ± 6.7 kg, height 173.3 ± 5.0 cm, VO2max 57.9 ± 5.8 ml·kg-1·min-1) performed a progressive incremental test and two submaximal workload tests (at 12 km·h-1 and 90 percent second ventilatory threshold) to determine the RE. There was significant correlation between EC INCLINA and RE measured at 12 km·h-1 (r = 0.49; p = 0.054) and at 90 percent second ventilatory threshold (r = 0.55; p = 0.027). In addition, EC INCLINA also was negatively correlated with peak blood lactate (r = -0.75; p = 0.001) and peak respiratory exchange rate (r = -0.80; p < 0.001). These findings suggest that EC INCLINA would be an alternative parameter employed to determine the endurance performance in recreational long-distance runners.

Effect of Aerobic Exercise on the Maximal Oxygen Uptake in Sedentary Healthy Adults: A Meta Analysis / 中国运动医学杂志

Objective Through this meta analysis of controlled clinical trials of the effect of aerobic exercise on the maximal oxygen uptake(VO_2max)in sedentary healthy adults,we attempt to provide evidence for exercise prescription.Methods MEDLINE search for controlled trials that involved in the effect of aerobic exercise on the VO_2max from 1976 to 2008 was conducted.The literatures were selected according to inclusion criteria and exclusion criteria.Review Manager 5.0 software provided a systematic evaluation for calculating VO_2 max Weighted Mean Difference with random effects model.Assessment of the sub-group of aerobic exercise intensity and literature publication bias were conducted.Results(1)Thirty five literatures were included in this review;involving 889 adults met the inclusion criteria.VO_2max Weighted Mean Difference is 3.61ml/kg/min,95%confidence interval 2.96～4.25ml/kg/min,with an increase of 13.2%,comparing with the average VO_2max values(27.26 ml/kg/min)before aerobic exercise.(2)The most effective exercise intensity was 70～80%VO_2max,71～80%HRmax and 61～70% HRR according to the sub.group of aerobic exercise intensity meta analysis.Conclusion VO_2max increased significantly due to participating in aerobic exercise in sedentary healthy adults.The results will provide a theoretical basis for me development of aerobic exercise prescription with appropriate intensity.

DEVELOPMENT OF VO_2max PREDICTION MODELS FROM 3-MINUTE WALK TEST / 体力科学

The purpose of the study was to develop new VO_2max prediction models for Japanese men using a 3-minute walk test. One hundred and twenty-seven Japanese men aged from 20 to 69 years were recruited as subjects of the present study. Maximal oxygen uptake (VO_2max) was measured with a maximal incremental test on a bicycle ergometer. The prediction models were derived using data of age, 3-minute walking distance (3MWD), and either BMI, waist circumference (WC), or %Fat. This data was cross-validated by using PRESS cross-validation procedures. 3MWD was significantly related to VO_2max (<i>r</i> = 0.54, P<0.001). The multiple correlation coefficients for the BMI, WC, and %Fat models, respectively, were 0.81, 0.82, and 0.85. The standard error of estimate (SEE) was 4.5, 4.4, and 4.1 ml·kg^-1·min^-1, respectively, for the BMI, WC, and %Fat models. All regression models demonstrated a high level of cross-validity supported by the minor shrinkage of the coefficient of determination and increment of SEE in the PRESS procedure. This study demonstrated that 3MWD was useful for predicting VO_2max accurately using VO_2max prediction models for Japanese men. The new non-exercise prediction equations derived in this study are applicable to estimating VO_2max in Japanese adult men.

DETERMINING THE DIFFERENCE IN MAXIMAL OXYGEN UPTAKE OF RUNNING AND CYCLING－ MRI EVALUATION OF MUSCULAR ACTIVITY LEVEL － / 体力科学

The purpose of this study was to determine the difference in the attainment rate of maximal oxygen uptake in cycling and running (%cycVO_2max). Seven healthy male subjects (22.9±1.3 yrs, 171.9±4.7 cm, 61.0±5.2 kg) participated in a maximal incremental exercise test for running and cycling. During the exercise testing, oxygen uptake, carbon dioxide output, respiratory exchange rate, minute ventilation, tidal volume, respiratory rate, and heart rate were measured. Attainment rates of each physiological measurement for cycling and running were shown as %cycVO_2max, %cycVCO_2max, %cycRER_max, %cycVE_max, %cycVt, %cycRR and %cycHR_max. Transverse relaxation time (T2)-weighted spin echo images were acquired before and after the exercise periods. Exercise-induced T2 values of each muscle and muscle-group are indices of muscular activity level, so the difference between the T2 value of cycling and running in each muscle or muscle group was shown as ΔT2_%. VO_2max in cycling was 92.2% of VO_2max in running. Significant correlations were observed between %cycVO_2max and %cycVCO_2max, %cycVO_2max and %cycRR. Furthermore, significant correlations were recognized between %cycVO_2max and ΔT2_% of the m. quadriceps femoris, %cycVCO_2max and ΔT2_% of the m. quadriceps femoris, %cycVCO_2max and the m. triceps surae, as well. These results show that the higher muscular activity level of the thigh in cycling increases the uptake of oxygen in the muscle. The T2 value shows that the uptake or redistribution of fluid within muscle is driven by the accumulation of lactate and inorganic phosphate. Therefore, the T2 value of maximal incremental exercise would reflect the anaerobic capacity of the muscle. Judging from the significant correlations between %cycVO_2max and %cycVCO_2max or %cycRR, the anaerobic capacity of each subject would also affect the difference between the maximal oxygen uptake of cycling and running.