Are early and late rate of force development differently influenced by fast-velocity resistance training?

This study examined the effect of fast-velocity concentric isokinetic resistance training (FV) on the rate of force development (RFD) at early (<100 ms) and late phases (>100 ms) of rising muscle force. Nine men participated in a 6-week resistance training intervention for the lower body, and nine matched subjects participated as controls (CON). During concentric isokinetic (180°s-1) knee extension training, subjects were instructed to do each contraction 'as fast and forcefully as possible'. Maximal muscle strength (MVC) and RFD (0-10, 0-20, ..., 0-250 ms from the onset of contraction) were measured during maximal voluntary isometric contraction of the knee extensors (KE). There were no significant changes in MVC of KE in both groups after intervention (FV = 314·2 ± 101·1 versus 338·7 ± 88·0 N{bullet operator}m, P>0·05; CON = 293·3 ± 94·8 versus 280·0 ± 72·2 N{bullet operator}m, P>0·05). The RFD increased 39-71% at time intervals up to 90 ms from the onset of the contraction (P<0·05), whereas no change occurred at later time intervals. Similarly, relative RFD (i.e.%MVC{bullet operator}s-1) (RFDr) increased 33-56% at time intervals up to 70 ms from the onset of the contraction (P<0·05). It can be concluded that a short period of resistance training performed with concentric fast-velocity isokinetic muscle contractions is able to enhance RFD and RFDr obtained at the early phase of rising muscle force. © 2013 The Authors Clinical Physiology and Functional Imaging © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

Isokinetic eccentric resistance training prevents loss in mechanical muscle function after running

The aim of the study was to verify whether 8 weeks of resistance training employing maximal isokinetic eccentric (IERT) knee extensor actions would reduce the acute force loss observed after high-intensity treadmill running exercise. It was hypothesized that specific IERT would induce protective effects against muscle fatigue and ultrastructural damages, preventing or reducing the loss in mechanical muscle function after running. Subjects were tested before and after IERT protocol for maximal isometric, concentric and eccentric isokinetic knee extensor strength (60 and 180 s-1). In a second session, subjects performed treadmill running (~35 min) and the previously mentioned measurements were repeated immediately after running. Subsequently, subjects were randomized to training (n = 12) consisting of 24 sessions of maximal IERT knee extensors actions at 180 s-1, or served as controls (n = 8). The effects of acute running-induced fatigue and training on isokinetic and isometric peak torque, and rate of force development (RFD) were investigated. Before IERT, running-induced eccentric torque loss at 180 s-1 was -8 %, and RFD loss was -11 %. Longitudinal IERT led to reduced or absent acute running-induced losses in maximal IERT torque at 180 s-1 (+2 %), being significantly reduced compared to before IERT (p < 0.05), however, RFD loss remained at -11 % (p > 0.05). In conclusion, IERT yields a reduced strength loss after high-intensity running workouts, which may suggest a protective effect against fatigue and/or morphological damages. However, IERT may not avoid reductions in explosive muscle actions. In turn, this may allow more intense training sessions to be performed, facilitating the adaptive response to running training. © 2013 Springer-Verlag Berlin Heidelberg.

Resistance training for explosive and maximal strength: Effects on early and late rate of force development

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Motor readiness and joint torque production in lower limbs of older women fallers and non-fallers

This study aimed to evaluate the motor response time and ability to develop joint torque at the knee and ankle in older women with and without a history of falls, in addition to investigating the effect of aging on these capacities. We assessed 18 young females, 21 older female fallers and 22 older female non-fallers. The peak torque, rate of torque development, rate of electromyography (EMG) rise, reaction time, premotor time and motor time were obtained through a dynamometric assessment and simultaneous electromyography. Surface EMGs of the rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF), gastrocnemius lateralis (GL) and tibialis anterior (TA) muscles were recorded. Knee extension and flexion peak torques were lower in older fallers than in non-fallers. Knee extension and flexion and ankle plantarflexion and dorsiflexion peak torques were lower in both older groups than in the younger group. The rate of EMG rise of the BF and the motor time of the TA were lower and higher, respectively, in older fallers than in the younger adults. The time to reach peak torque in knee extension/flexion and ankle plantarflexion/dorsiflexion and the motor times of the RF, VL, BF and GL were higher in both older groups than in the younger groups. The motor time of the TA during ankle dorsiflexion and the knee extension peak torque were the major predictors of falls in older women, accounting for approximately 28% of the number of falls. Thus, these results further reveal the biomechanical parameters that affect the risk of falls and provide initial findings to support the prescription of exercises in fall prevention programs. © 2013 Elsevier Ltd.

Avaliação dos indicadores nutricionais e da composição corporal em hepatopatas crônicos e a relação com a etiologia e gravidade da doença

Pós-graduação em Bases Gerais da Cirurgia - FMB

Efeitos do treinamento resistido sobre a variabilidade da frequência cardíaca, capacidade funcional e força muscular periférica na DPOC

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise do princípio centrando do método pilates e de indicadores de resistência e estabilidade da coluna lombar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Exercício resistido em cardiopatas: revisão sistemática da literatura e análise do comportamento autonômico em recuperação pós-exercício resistido aplicado de forma aguda

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo do sinal eletromiográfico em exercícios isométricos em diferentes velocidades de contração

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos do treinamento resistido concêntrico versus excêntrico sobre respostas funcionais, clínicas e bioquímicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da distribuição da pressão plantar e equilíbrio de diabéticos neuropatas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Parâmetros do sinal eletromiográfico aplicados ao estudo da fadiga muscular localizada: caracterização do processo; análise de reprodutibilidade e multivariada

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

O efeito de diferentes intervalos de recuperação entre as séries do treinamento com pesos, nas respostas neuromusculares e do hormônio do crescimento, em idosas treinadas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito do treinamento de força e potência na curva força-tempo isométrica e na ativação muscular em idosos com doença de Parkinson

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A eletromiografia em treinamento resistido: avaliação da fadiga muscular, adaptações e relações com parâmetros subjetivos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)