ABSTRACT
Abstract The aim of this study was to propose a mechanical device that could increase the mechanical load during the entire eccentric (ECC) action on a knee flexor machine and to compare the muscular activity when the device was used during a testing protocol. Fifteen physically active women were recruited, and they performed two protocols: control and eccentric overload. Control protocol was performed with concentric (CON) and ECC actions with similar load (60% of one repetition maximum) whilst eccentric overload protocol consisted of ECC actions with 40% more load than CON actions. Muscular activation was measured using surface electromyography of the biceps femoris (BF) and the gastrocnemius medialis (GM) muscles. ECC actions presented a higher muscular activation during eccentric overload protocol than control protocol for BF (p = 0.032), but not for the GM (p = 0.439). The mechanical device increased the mechanical load during the ECC muscle action and consequently increased the amplitude of the neural drive to the BF muscle; however, it did not increase the amplitude of the neural drive to the GM muscle.
Resumo O objetivo deste estudo foi propor um dispositivo mecânico que acoplado a uma cadeira flexora aumente a carga mecânica durante toda a ação excêntrica (ECC) e comparar a atividade muscular durante a utilização do dispositivo proposto. Quinze mulheres fisicamente ativas foram recrutadas e realizaram dois diferentes protocolos (controle e sobrecarga ECC). O protocolo controle foi realizado com ações concêntricas (CON) e ECC com carga iguais (60% de uma repetição máxima), enquanto o protocolo de sobrecarga ECC consistiu em ações ECC com 40% mais de carga do que as ações CON. A ativação muscular dos músculos biceps femoris (BF) e gastrocnemius medialis (GM) foi medida por meio de eletromiografia de superfície. Durante as ações ECC foi observada uma maior ativação do BF durante o protocolo de sobrecarga quando comparado ao protocolo controle (p = 0,032). No entanto, GM não apresentou diferenças na ativação entre os protocolos (p = 0,439). O dispositivo mecânico proposto foi capaz de aumentar a carga durante a ação ECC e, consequentemente, a atividade muscular do BF.
Subject(s)
Humans , Female , Adult , Resistance Training/standards , Motor Neurons/physiology , Muscle, Skeletal , Electromyography , Resistance Training/methods , Hamstring Muscles , Muscle ContractionABSTRACT
ABSTRACT Background Sarcopenic obesity is associated with disability in older people, especially in women. Resistance exercises are recommended for this population, but their efficacy is not clear. Objective To evaluate the effects of a progressive resistance exercise program with high-speed component on the physical function of older women with sarcopenic obesity. Method Twenty-eight women 65 to 80 years old, with a body mass index ≥30kg/m2 and handgrip strength ≤21kg were randomly allocated to two groups. The experimental group underwent a 10-week resistance exercise program designed to improve strength, power, and endurance of lower-limb muscles, with open chain and closed chain exercises. The control group had their health status monitored through telephone calls. The primary outcomes were lower limb muscle performance measured by knee extensor strength, power and fatigue by isokinetic dynamometry, and mobility measured by the Short Physical Performance Battery and by gait velocity. The secondary outcome was health-related quality of life assessed by the SF-36 Questionnaire. Results The average rate of adherence was 85%, with few mild adverse effects. There were no significant between-group differences for any of the outcomes. Conclusion In this study, a progressive resistance exercise program with high-speed component was not effective for improving the physical function of older women with sarcopenic obesity.
Subject(s)
Humans , Female , Muscle Strength/physiology , Resistance Training/methods , Sarcopenia/physiopathology , Obesity/physiopathology , Exercise , Muscle, Skeletal/physiopathology , Exercise Therapy , Resistance Training/standardsABSTRACT
Abstract Hypertension affects 25% of the world's population and is considered a risk factor for cardiovascular disorders and other diseases. The aim of this study was to examine the evidence regarding the acute effect of exercise on blood pressure (BP) using meta-analytic measures. Sixty-five studies were compared using effect sizes (ES), and heterogeneity and Z tests to determine whether the ES were different from zero. The mean corrected global ES for exercise conditions were -0.56 (-4.80 mmHg) for systolic BP (sBP) and -0.44 (-3.19 mmHg) for diastolic BP (dBP; z ≠ 0 for all; p < 0.05). The reduction in BP was significant regardless of the participant's initial BP level, gender, physical activity level, antihypertensive drug intake, type of BP measurement, time of day in which the BP was measured, type of exercise performed, and exercise training program (p < 0.05 for all). ANOVA tests revealed that BP reductions were greater if participants were males, not receiving antihypertensive medication, physically active, and if the exercise performed was jogging. A significant inverse correlation was found between age and BP ES, body mass index (BMI) and sBP ES, duration of the exercise's session and sBP ES, and between the number of sets performed in the resistance exercise program and sBP ES (p < 0.05). Regardless of the characteristics of the participants and exercise, there was a reduction in BP in the hours following an exercise session. However, the hypotensive effect was greater when the exercise was performed as a preventive strategy in those physically active and without antihypertensive medication.
Resumo A hipertensão arterial afeta 25% da população mundial e é considerada um fator de risco para distúrbios cardiovasculares e outras doenças. O objetivo deste estudo foi examinar as evidências sobre o efeito agudo do exercício sobre a pressão arterial (PA) utilizando medidas metanalíticas. Sessenta e cinco estudos foram comparados com tamanho de efeito (TE), testes de heterogeneidade, e teste Z para determinar se os TE eram diferentes de zero. A média dos TE globais corrigida para as condições do exercício foram -0,56 (-4,80 mmHg) para a PA sistólica (PAs) e -0,44 (-3,19 mmHg) para a PA diastólica (PAd; z ≠ 0 para todos; p < 0,05). A redução da PA foi significativa independente da PA inicial do participante, sexo, nível de atividade física, ingestão de medicamentos anti-hipertensivos, tipo de medição da PA, hora do dia na qual a PA foi medida, tipo de exercício realizado, e programa de treinamento (p < 0,05 para todos). Testes ANOVA revelaram que as reduções da PA eram maiores se os participantes eram do sexo masculino, não recebiam medicação anti-hipertensiva, eram fisicamente ativos e se o exercício realizado era jogging. Uma correlação inversa significativa foi encontrada entre idade e TE da PA, índice de massa corporal (IMC) e TE da PAs, duração da sessão de exercício e TE da PAs, e número de séries realizadas no programa de exercícios de resistência e TE da PAs (p < 0,05). Independente das características dos participantes e do exercício, houve uma redução na PA poucas horas após uma sessão de exercícios. No entanto, o efeito hipotensor foi maior quando o exercício foi realizado como uma estratégia preventiva em pessoas fisicamente ativas e sem medicação anti-hipertensiva.