Muscle endurance measurement using a progressive workload method may reduce pain sensation in the subject. This study aimed to examine the relationships between force-time parameters during sustained static gripping as measured by maximal voluntary contraction (MVC) using either a progressive workload (PW) or a constant workload (CW). Sixteen subjects performed sustained static gripping with 7 ...

Whether the transition in fatigue processes between "low-intensity" and "high-intensity" contractions occurs gradually, as the torque requirements are increased, or whether this transition occurs more suddenly at some identifiable "threshold", is not known. We hypothesized that the critical torque (CT; the asymptote of the torque-duration relationship) would demarcate distinct profiles of centr...

Transcranial magnetic stimulation (TMS) of the motor cortex during a maximal voluntary contraction (MVC) permits functionally relevant measurements of muscle group relaxation rate (i.e., when muscles are actively contracting under voluntary control). This study's purpose was twofold: (1) to explore the impact of muscle length on TMS-induced plantar flexor relaxation rate; and (2) to incorporate...

This study examined the effects of cycling training on mechanomyographic median power frequency (MMGMDF)–torque relationships vastus lateralis (VL). Ten males (Age ± SD; 20.20 1.87 years) and 14 females (21.93 5.33 performed isometric trapezoidal muscle actions with knee extensors at 40% maximal voluntary contraction (MVC) before (PRE) following 10 weeks same absolute submaximal torque as pre-t...

Methods Subjects are 20 healthy males. Maximum Voluntary Contraction (MVC) of elbow flexor was measured using a strain gauge prior to exercise (MVC1). Subjects received acupuncture stimulation before the exercise on their biceps brachii. The stimulation is either deep needling (targeting muscle; mACU) or superficial needling (sACU). The exercise protocol contains 5 sets * 10 repetitions of maxi...

The corticospinal pathway is the major pathway controlling human voluntary movements. After strong voluntary contractions, the efficacy of corticospinal transmission to elbow flexors is reduced for approximately 90 s, and this limits motoneuronal output. This reduction may reflect activity-dependent changes at cortico-motoneuronal synapses. We investigated whether similar changes occur in a leg...

Recurrence quantification analysis (RQA) is a nonlinear method providing information on the temporal structure of time series. RQA has been extensively used to explore various noisy and nonstationary physiological signals. However, application force signals acquired during voluntary fatiguing contractions performed until exhaustion remain be investigated. We aimed sensitivity percentage determi...

The ability of the latissimus dorsi muscle (LD) to participate as an accessory inspiratory muscle has been the subject of controversy. Electromyographic (EGM) activity of LD was evaluated in 11 healthy subjects (aged 30 +/- 2 yrs; forced expiratory volume in one second (FEV1) 106 +/- 5% predicted; maximal inspiratory pressure (Pmax), 120 +/- 6 cmH2O) under different breathing conditions. The ip...

We determined the effects of static and dynamic muscle contraction at equivalent workloads on central aortic pressure and wave reflection. At random, 14 healthy men and women (23 +/- 5 yr of age) performed a static handgrip forearm contraction [90 s at 30% of maximal voluntary contraction (MVC)], dynamic handgrip contractions (1 contraction/s for 180 s at 30% MVC), and a control trial. During s...

It is not fully clear whether intramuscular oxidative metabolism contributes to total adenosine triphosphate (ATP) production during forearm isometric exercise at varying intensities. We tested hypothesis that oxidative metabolism with intramuscular O2 contributes to lessen the dependence on anaerobic metabolism, in particular phosphocreatine (PCr) breakdown. Seven male subjects were tested for...