Assessing the robustness of muscle strength and physical performance measures in women older than 40 years: a test-retest reliability study.

OBJECTIVES: This study investigated the test-retest reliability and minimal detectable change (MDC) of muscle strength and physical performance tests in women older than 40 years. METHODS: A total of 113 women, aged 58 ± 11 years (82% postmenopausal women), with a body mass index of 28.5 ± 5.8 kg/m 2 , participated in this study. One-repetition maximum (1RM) tests were conducted for seven strength exercises: 45° leg press, bench press, leg extension, pec deck, wide-grip lateral pull-down, leg curl, and seated cable row, with a retest after 48 hours. Timed Up and Go (TUG), 6-minute walk, and 30-second sit-to-stand tests were performed on the same day and retested after 72 hours. The tests and retests were administered by the same evaluators. Relative reliability (consistency of participant rank between test-retest) was assessed using the intraclass correlation coefficient for consistency and agreement, and absolute reliability (precision of score) was assessed using the MDC based on the standard error of prediction. RESULTS: The 1RM and performance tests exhibited excellent reliability: 45° leg press (consistency, 0.99; agreement, 0.98), bench press (consistency, 0.96; agreement, 0.96), leg extension (consistency, 0.93; agreement, 0.91), pec deck (consistency, 0.90; agreement, 0.88), wide-grip lateral pull-down (consistency, 0.91; agreement, 0.89), leg curl (consistency, 0.84; agreement, 0.83), seated cable row (consistency, 0.92; agreement, 0.94), TUG (consistency, 0.87; agreement, 0.87), 6-minute walk (consistency, 0.96; agreement, 0.95), and 30-second sit to stand (consistency, 0.85; agreement, 0.80). These tests showed meaningful MDC values, particularly for the 1RM test performed on the machine and the 30-second sit-to-stand test: 45° leg press, 22.2 kg (15%); bench press, 4.9 kg (19%); leg extension, 9.2 kg (35%); pec deck, 8.8 kg (44%); wide-grip lateral pull-down, 9.4 kg (31%); leg curl, 9.2 kg (51%); seated cable row, 11.4 kg (29%); TUG, 1.4 seconds (20%); 6-minute walk, 50.9 m (10%); and 30-second sit to stand, 4.6 reps (30%). CONCLUSIONS: Although the muscle strength and physical performance tests demonstrate excellent relative reliability in women older than 40 years, they exhibit low absolute reliability, particularly the 1RM test performed on the machine and the 30-second sit-to-stand test. Therefore, although these tests show good consistency in the positioning of women within the group after repeated measures, their precision measure is relatively low (high fluctuation). Changes in these tests that are smaller than the MDC may not indicate real changes in women at middle age and older.

Young soccer players with higher somatic maturation are stronger, more powerful and faster than those with lower maturation / Jovens futebolistas de maior maturação somática são mais fortes, potentes e velozes que os de menor maturação

ABSTRACT The identification of young soccer players' maturation level throughout puberty is crucial to verify the influence of aspects that interfere on sport performance, such as body height and physical capacities. The aim of the present study was to verify the differences in physical performance of young soccer players in maturation stages before and after peak height velocity. This study comprised 49 soccer players (14.49 ± 1.00 yrs) belonging to the youth teams of a club in the city of Fortaleza. Body weight, height and trunk-cephalic height were measured. Somatic maturation was estimated using distance in years from peak height velocity (DPHV). 10 Meters Sprint and 20 Meter Flying Sprint, Modified Illinois, Jump Height (CMJ), RAST and Yo Yo IRT 1 tests were applied. Standardized Mean Difference (SMD) and Confidence Intervals (CI = 90%) were used to compare the study variables (PRE-PHV vs POST-PHV). Our findings showed that POST-PHV group showed higher values in CMJ (3/3/97, Very likely) and RAST (peak, average, minimum power) and lower in the 20 Meter Flying Sprint (100/0/0, Most Likely) when compared to the PRE-PHV group. We concluded that young soccer players with somatic maturation after peak height velocity presented better capacity of lower limb strength, anaerobic power and speed.

RESUMO A identificação do nível maturacional de futebolistas em formação, ao longo da puberdade, é fundamental para verificar a influência de aspectos que interferem no desempenho esportivo, tais como o tamanho corporal e as capacidades físicas. O objetivo do presente estudo foi verificar as diferenças de desempenho físico de jovens futebolistas em estágios maturacionais pré e pós pico de velocidade de crescimento. Participaram do estudo 49 futebolistas (14,49 ± 1,00 anos) das categorias de base de um clube da cidade de Fortaleza. Foram aferidas a massa corporal, a estatura e a altura tronco-cefálica. A maturação somática foi estimada por meio da distância ao pico de velocidade de crescimento (DPVC). Foram realizados os testes Sprint 10 metros e 20 metros lançado, Illinois modificado, Altura do salto (CMJ), RAST e o Yo Yo IRT 1. As Diferenças de Média Estandardizada (DME) e Intervalo de Confiança (IC = 90%) foram utilizados para comparar as variáveis do estudo (PRÉ-PVC vs PÓS-PVC). Os nossos achados mostraram que o grupo PÓS-PVC apresentou valores mais elevados no CMJ (0/3/97, Very likely) e no RAST (potência máxima, média, mínima) e inferiores no Sprint 20m L (100/0/0, Most Likely), quando comparado ao grupo PRÉ-PVC. Concluimos que jovens futebolistas com maturação somática pós pico de velocidade de crescimento apresentam melhor capacidade de força de membros inferiores, potência anaeróbia e velocidade.

The influence of the ACTN3 R577X polymorphism in the responsiveness to post-activation jump performance enhancement in untrained young men / A influência do polimorfismo R577X do gene ACTN3 na responsividade à melhora de desempenho de salto pós-ativação em indivíduos jovens destreinados

ABSTRACT We aimed to investigate the influence of alpha-actinin-3 (ACTN3) R577X polymorphism on responsiveness to post-activation performance enhancement (PAPE) of countermovement jumps (CMJ) in untrained subjects. Sixteen untrained men were allocated into two groups according to their ACTN3 gene alleles: homozygous for the X allele (XX, n = 9) or homozygous for the R allele (RR, n = 7). CMJ height, mean power output and vertical force were determined twice (CMJ1 and CMJ2) in two conditions: control (CON) and potentiated (PAPE). In the CON condition, CMJ were performed before and after a 15-min rest. In the PAPE condition, CMJ were performed 15 min before and 4 min following five squats with a 5-repetition maximum (5RM) load. Different conditions were applied on separate days in a randomized order. Statistical analysis involved three-way ANOVAs to compare the differences between conditions (CON and PAPE), time (CMJ1 and CMJ2), and groups (XX and RR). Significance level considered was p < 0.05. Effect sizes were calculated as Cohen's d. The effect sizes for changes in CMJ height for CON and following pre-activation for PAPE were 0.04 and 0.08, respectively. No significant differences were found for CMJ height between XX and RR at baseline (1.07 ± 2.54 cm e -0.82 ± 2.56 cm, respectively). No differences were found (p>0.05) in responsiveness to PAPE between the groups (XX = -0.20 ± 1.6 cm and RR = -0.81 ± 2.7 cm). We conclude that ACTN3 gene polymorphisms does not influence responsiveness to PAPE.

RESUMO Tivemos como objetivo investigar a influência do polimorfismo do gene ACTN3 na responsividade à potencialização do desempenho de salto com contra movimento (CMJ) pós-ativação (PAPE). Dezesseis homens destreinados foram divididos em dois grupos: homozigotos para os alelos X (XX, n = 9) ou R (RR, n = 7). A altura de CMJ, a potência média e a força vertical aplicada durante o salto pelos participantes foram determinadas duas vezes (CMJ1 e CMJ2) em duas condições: controle (CON) e potencializado (PAPE). Na condição CON, os CMJ foram realizados antes e depois de um período de 15 minutos de repouso. Na condição PAPE, os CMJ foram realizados 15 minutos antes e 4 minutos após a realização de cinco agachamentos com carga de cinco repetições máximas (5RM). As diferentes condições foram realizadas em dias separados e em ordem randomizada. ANOVAs fatoriais de três caminhos foram utilizadas para comparar diferenças entre condições, tempos e grupos. O tamanho do efeito foi calculado pelo d de Cohen. Os tamanhos do efeito para alterações na altura de CMJ para os grupos CON e PAPE foram 0.04 e 0.08, respectivamente. Não houve diferenças significantes entre os grupos XX e RR na altura de salto em condição basal (1.07 ± 2.54 cm e -0.82 ± 2.56 cm, respectivamente). Não houve diferenças significativas na responsividade à PAPE entre os grupos (XX = -0.20 ± 1.6 cm e RR = -0.81 ± 2.7 cm). O polimorfismo do gene ACTN3 parece não ser influenciar isoladamente a responsividade à PAPE.

Moderate Aerobic Training Decreases Blood Pressure but No Other Cardiovascular Risk Factors in Hypertensive Overweight/Obese Elderly Patients.

Hypertension and obesity are prevalent diseases in elderly people, and their combination can cause deleterious effects on physiological system. Moderate intensity aerobic training (MIAT) seems to be a beneficial approach to control and treat these diseases separately. However, few studies have investigated the impact of MIAT on cardiovascular risk factors associated with these conditions (i.e., elevated blood pressure values, blood markers, and body composition). Therefore, the present study was designed to investigate the effects of MIAT on blood pressure, blood markers, and body composition in hypertensive overweight/obese elderly patients. Twenty-four hypertensive overweight/obese elderly patients were randomized into control group (CG) and training group (TG), submitted to 12 weeks of MIAT of 50 min, 3 days per week, at 60% of maximal HR (heart rate). There was a decrease in diastolic blood pressure (-10.1 ± 3.3; p = .01; effect size = 1.29) and mean arterial pressure (MAP; -8.2 ± 3.7; p = .04; effect size = 0.94) following 12 weeks of training in the TG as compared with baseline. There was an increase in triacylglycerol levels in the TG (+0.1 ± 0.0; p = .02). There were no significant changes in body composition for both groups. The present study revealed that 12 weeks of MIAT can decrease blood pressure in hypertensive obese elderly patients, with no significant modifications in blood markers and body composition.

Consumption of cherries as a strategy to attenuate exercise-induced muscle damage and inflammation in humans / El consumo de cerezas como estrategia de mitigación del daño muscular y la inflamación en seres humanos

Background: exercise-induced muscle damage (EIMD) is a multifactorial phenomenon that induces muscle function loss because of mechanical and immune stressor stimuli. This immunological stress is mostly caused by inflammation and increased oxidative status. Cherries are fruits that contain a phenolic compound known as anthocyanin, which serves as a pigment in natura. However, research suggests this pigment might provide a potent antioxidant and anti-inflammatory strategy when consumed by humans. Objectives: the aim of this study was to critically review the literature on cherry consumption focusing on identifying protective strategies against EIMD conferred by it. Methods: a research was performed in PubMed database. This review presents the results about cherry consumption and EIMD. Results: the articles identified in this review support the notion that tart cherry consumption attenuates EIMD symptoms after intense exercise bouts. This attenuation seems to be related to the antioxidant and anti-inflammatory properties of anthocyanins and other phenolic compounds present in tart cherries. Conclusion: daily consumption of tart cherries may attenuate inflammatory and oxidative responses to EIMD, leading to faster recovery after exercise bouts (AU)

Introducción: el daño muscular es un fenómeno multifactorial que conduce a la pérdida de la función muscular como resultado de la tensión mecánica e inmune. Este estrés inmunológico es causado principalmente por la inflamación y el estado oxidativo aumentado. Las cerezas son frutas que contienen antocianinas con compuestos fenólicos conocidos, que sirven como pigmento en la naturaleza. Entre tanto, los estudios sugieren que este pigmento puede promover un potente efecto antioxidante y antiinflamatorio cuando se consume por los seres humanos. Objetivos: el objetivo de este estudio fue realizar una revisión crítica de la literatura sobre el consumo de cerezas, con un enfoque en la identificación de las estrategias de protección contra el daño muscular. Métodos: se realizó una encuesta en la base de datos PubMed. Esta revisión presenta los resultados para el consumo de cerezas y daño muscular. Resultados: los artículos que se encuentran en esta revisión apoyan la idea de que el consumo de cerezas alivia los síntomas de daño muscular después de las sesiones de ejercicio. Esta atenuación parece estar relacionada con las propiedades antioxidante y antiinflamatoria de las antocianinas y otros compuestos fenólicos presentes en las cerezas. Conclusión: el consumo diario de cerezas puede aliviar la respuesta inflamatoria y oxidativa de los entrenamientos y conseguir una recuperación más rápida de los marcadores de daño muscular (AU)

Effects of downhill walking training on aerobic and neuromuscular fitness of young adults / Efeitos da caminhada em declive na aptidão aeróbia e neuromuscular em adultos jovens

Abstract Eccentric exercise training using low intensity-high volume approach has been performed to improve maximal muscle strength and power. The aim of this study was to compare the effects of short-term downhill walking and level walking training on lower limb strength and maximal oxygen uptake of active individuals. Eighteen young adults were divided into level walking group (n = 9) or downhill walking training group (n = 9). Both groups performed a four-week training program. The level walking group performed seven level walking sessions per week, while the downhill walking group walked downhill (-16%) in the same weekly frequency. One week before and one week after the training protocol, maximal oxygen uptake, muscle-bone cross-sectional area and isometric peak torque of knee extensors and plantar flexors were assessed for both groups. A significant group vs. time interaction was found only for cross sectional area of plantar flexors (PF), showing increases for the downhill walking group (112.6 ± 28.9 cm2 vs. 115.9 ± 29 cm2) but not for the level walking group (94.9 ± 23.3 cm2vs. 94.6 ± 228 cm2). Maximal oxygen uptake remained unaltered after training for both groups and IPT was increased after training for both groups. It was concluded that short-term downhill walking training does not seem to be efficient in promoting improvements in cardiorrespiratory fitness of young adults. However, it seems to promote gains in some variables related to neuromuscular fitness.

Resumo O treinamento excêntrico de baixa intensidade e alto volume vem sendo adotado para desenvolver a força e a potência muscular. O objetivo deste estudo foi comparar os efeitos do treinamento de caminhada em declive e em plano, em parâmetros de força de membros inferiores e consumo máximo de oxigênio de indivíduos ativos. Dezoito adultos foram separados em grupos de treinamento em plano (GTP - n = 9) em declive (GTD - n = 9). Ambos realizaram um programa de treinamento de 4 semanas. O GTP realizou sete sessões semanais de caminhada no plano, enquanto o GTD caminhou em declive (-16%). Uma semana antes e uma semana após o treinamento, foram medidos o consumo máximo de oxigênio, área de secção transversa músculo-óssea e o pico de torque isométrico dos extensores do joelho e flexores plantares dos participantes. Interação significante grupo-tempo foi identificada apenas para a área de secção transversa dos flexores plantares, demonstrando aumentos para o grupo GTD (112,6 ± 28,9 cm2vs. 115,9 ± 29 cm2), mas não para o GTP (94,9 ± 23,3 cm2vs. 94,6 ± 228 cm2). O consumo máximo de oxigênio permaneceu inalterado após o treinamento para ambos os grupos e o pico de torque isométrico aumentou significantemente após o treinamento para ambos os grupos. Concluímos, então, que um treinamento de caminhada em declive de curto prazo parece não ser eficiente na promoção de melhoras significativas de parâmetros cardiorrespiratórios de adultos jovens, embora seja efetivo no incremento de algumas variáveis relacionadas à aptidão neuromuscular.

Postactivation potentiation biases maximal isometric strength assessment.

Postactivation potentiation (PAP) is known to enhance force production. Maximal isometric strength assessment protocols usually consist of two or more maximal voluntary isometric contractions (MVCs). The objective of this study was to determine if PAP would influence isometric strength assessment. Healthy male volunteers (n = 23) performed two five-second MVCs separated by a 180-seconds interval. Changes in isometric peak torque (IPT), time to achieve it (tPTI), contractile impulse (CI), root mean square of the electromyographic signal during PTI (RMS), and rate of torque development (RTD), in different intervals, were measured. Significant increases in IPT (240.6 ± 55.7 N·m versus 248.9 ± 55.1 N·m), RTD (746 ± 152 N·m·s(-1) versus 727 ± 158 N·m·s(-1)), and RMS (59.1 ± 12.2% RMSMAX versus 54.8 ± 9.4% RMSMAX) were found on the second MVC. tPTI decreased significantly on the second MVC (2373 ± 1200 ms versus 2784 ± 1226 ms). We conclude that a first MVC leads to PAP that elicits significant enhancements in strength-related variables of a second MVC performed 180 seconds later. If disconsidered, this phenomenon might bias maximal isometric strength assessment, overestimating some of these variables.

Monitoramento de marcadores de dano muscular durante um programa de quatro semanas de treinamento de caminhada em declive / Marcadores de monitoreo de daño muscular durante un programa de cuatro semanas de entrenamiento a pie cuesta abajo / Monitoring muscle damage markers during a four-week downhill walking exercise program

Eccentric-based exercise is known to induce muscle damage (MD). The purpose of this study was to investigate effect of downhill walking (DW) sessions on MD and aerobic markers in young adults. Eight male subjects were submitted to a 4-week DW periodized exercise program. Subjects' soreness (SOR) was assessed each training day. Serum creatine quinase activity (CK) was collected before the first training session, and at the end of each of the four weeks. Oxygen uptake (VO2) and perceived exertion (PE) were assessed during the last training session every week. Increases in SOR were found only at the third and fourth training days. Increased CK concentration was found at the third training week. No significant increases in VO2 and PE were found throughout the program. We concluded that DW sessions elicit significant MD, but not enough to impair it in further sessions. Therefore, DW can be used as a training protocol following proper periodization.

Exercícios excêntricos costumam induzir dano muscular (DM). O objetivo deste estudo foi investigar respostas aeróbias e de DM a sessões de caminhada em declive (CaED) em adultos. Oito voluntários realizaram um programa periodizado de treinamento de CaED. A dor muscular (DMIT) foi coletada durante todos os dias de treinamento. A atividade sérica de creatina quinase (CK) foi coletada antes da primeira sessão e ao final das semanas 1-4. O consumo de oxigênio (VO2) e a percepção de esforço (PE) foram coletados durante a última sessão de treinamento de cada semana. Aumentos na DMIT foram identificados no terceiro e quarto dias de treinamento. Os valores de CK se apresentaram aumentados na terceira semana. Não foram identificadas diferenças nos valores obtidos de VO2 e PE. Concluímos que sessões de CaED induzem DM, porém este não afeta sessões posteriores. Portanto, a CaED pode ser utilizada como um método de treinamento, possibilitando sua periodização.

Ejercicio excéntrico desacostumbrado es conocido por inducir daño muscular (DM). El objetivo de este estudio fue investigar las respuestas a sesiones de caminar cuesta abajo (DW) en los adultos jóvenes, la evaluación de MD y los marcadores de aeróbicos. Ocho sujetos varones fueron sometidos a un programa de ejercicios de periodización de DW de 4 semanas. El dolor de los sujetos (SOR) se evaluó todos los días de entrenamiento. Actividad de la creatina quinasa sérica (CK) se recogió antes de la primera sesión de entrenamiento, y al final de las semanas 1-4. El consumo de oxígeno (VO2) y la percepción subjetiva del esfuerzo (PE) se evaluaron durante la última sesión de entrenamiento cada semana. Los aumentos en SOR se encontraron sólo en los tercero y cuarto día de entrenamiento. El aumento de la concentración de CK se encuentra en la tercera semana de entrenamiento. No hay un aumento significativo en el VO2 y PE se encuentran en todo el programa. Llegamos a la conclusión de que las sesiones DW provocan MD significativo, pero no lo suficiente como para poner en peligro otras sesiones. Por lo tanto, DW puede ser adoptado como método de entrenamiento, permitiendo periodización adecuada.

Exercise-induced muscle damage and running economy in humans.

Running economy (RE), defined as the energy demand for a given velocity of submaximal running, has been identified as a critical factor of overall distance running performance. Plyometric and resistance trainings, performed during a relatively short period of time (~15-30 days), have been successfully used to improve RE in trained athletes. However, these exercise types, particularly when they are unaccustomed activities for the individuals, may cause delayed onset muscle soreness, swelling, and reduced muscle strength. Some studies have demonstrated that exercise-induced muscle damage has a negative impact on endurance running performance. Specifically, the muscular damage induced by an acute bout of downhill running has been shown to reduce RE during subsequent moderate and high-intensity exercise (>65% VO2max). However, strength exercise (i.e., jumps, isoinertial and isokinetic eccentric exercises) seems to impair RE only for subsequent high-intensity exercise (~90% VO2max). Finally, a single session of resistance exercise or downhill running (i.e., repeated bout effect) attenuates changes in indirect markers of muscle damage and blunts changes in RE.