The purpose of this study was to investigate if force enhancement (FE) in vivo is influenced by stretch-induced changes of muscle architecture. Therefore, 18 subjects performed maximum voluntary isometric (100 degree knee flexion angle) and isometric-eccentric-isometric stretch contractions (80 degrees-100 degrees; ω=60 degrees.s(-1)) whereby pennation angle and fascicle length of vastus latera...

Recently it was demonstrated that postactivation potentiation (PAP), which refers to the enhancement of the muscle twitch torque as a result of a prior conditioning contraction, increased the maximal rate of torque development of tetanic and voluntary isometric contractions (3). In this study, we investigated the effects of PAP and its decay over time on the load-velocity relation. To that purp...

The influences of aging in muscle recruitment are still unclear. We used an isometric contraction protocol and an EMG–driven muscle model to estimate the contribution of each component of triceps surae muscle to ankle torque, in both young adults and elderly. Six subjects were enrolled in the study, 3 young and 3 elderly. The experimental protocol consists in two sustained contractions of 20% a...

We examined the effect of low-load, elastic band resistance training with blood flow restriction (BFR) on muscle size and arterial stiffness in older adults. Healthy older adults (aged 61-85 years) were divided into BFR training (BFR-T, n = 9) or non-BFR training (CON-T, n = 8) groups. Both groups performed low-load arm curl and triceps down exercises (four sets, total 75 repetitions for each) ...

Previously, a novel technique was proposed to quantify the relationship between the muscle stiffness and its nonfatigue contraction intensity. The method extended the measured range of isometric contraction to 100% maximum voluntary contraction (MVC) using an ultrasonic shear wave measurement setup. Yet, it has not been revealed how this relationship could be affected by factors like age or sex...

Lower limb actions such as jumping, standing and squatting all require both legs to act equally to provide the most efficient movement, and limit the development of bilateral asymmetries which may lead to unilateral trauma and reduced performance. In this study ten male volleyball players with age ranged from eighteen to twenty four years of Lakshmibai National Institute of Physical Education, ...

After active lengthening contractions, a given amount of force can be maintained with less muscle activation compared to pure isometric contractions at the same muscle length and intensity. This increase in neuromuscular efficiency is associated with mechanisms of stretch-induced residual force enhancement. We hypothesized that stretch-related increase in neuromuscular efficiency reduces fatiga...

We conducted two experiments to determine how differences in muscle contraction levels, muscle contraction types, and movement duration affect degree of post-exercise depression (PED) after non-exhaustive, repetitive finger movement. Twelve healthy participants performed repetitive abduction movements of the right index finger at 2 Hz. In experiment 1, we examined the effects of muscle contract...

INTRODUCTION Hypertension is a major risk factor contributing to cardiovascular disease, which is the number one cause of deaths worldwide. Although antihypertensive medications are effective at controlling blood pressure, current first-line treatment for hypertension is nonpharmacological lifestyle modifications. Recent studies indicate that isometric resistance training (IRT) may also be effe...

Torque depression (TD) is the reduction in steady-state isometric torque following active muscle shortening when compared with a purely isometric contraction at the same muscle length and level of activation. The purpose of the present study was to assess spinal and supraspinal excitability in the TD state during submaximal contractions of the dorsiflexors. Eleven young (24 ± 2 yrs) males perfo...