In an experiment, we examined the effect of intermittency (from 25.6 Hz to 0.2 Hz) of visual information on continuous isometric force production as a function of force level (5%, 10%, 25%, and 50% of maximal voluntary contraction [MVC]). The amount of force variability decreased and the irregularity of force output increased as a function of increased visual intermittency rate. Vision was foun...

The origin of the well-documented discrepancy between maximum voluntary and in vitro tetanic eccentric strength has yet to be fully understood. This study aimed to determine whether surface EMG measurements can be used to reproduce the in vitro tetanic force-velocity relationship from maximum voluntary contractions. Five subjects performed maximal knee extensions over a range of eccentric and c...

Seiza is a Japanese traditional floor sitting style, sitting down with both legs set at about a 180 degree angle and both femurs on both lower legs. We examined the influence of the somatic dysesthesia and decrease in voluntary toe flexion strength (VTF) induced by Seiza on the center of pressure (COP) sway. Fifteen adults participated in this experiment. COP Sway was measured immediately after...

A hallmark of the age-related neural reorganization is that old versus young adults execute typical motor tasks by a more diffuse neural activation pattern including stronger ipsilateral activation during unilateral tasks. Whether such changes in neural activation are present already at middle age and affect bimanual interactions is unknown. We compared the amount of associated activity, i.e., ...

OBJECTIVE To investigate the acute residual hormonal and neuromuscular responses exhibited following a single session of mechanical vibration applied to the upper extremities among different acceleration loads. METHODS Thirty male students were randomly assigned to a high vibration group (HVG), a low vibration group (LVG), or a control group (CG). A randomized double-blind, controlled-paralle...

We investigated the influence of nociceptive stimulation on the accuracy of task execution and motor unit spike trains during low-force isometric contractions. Muscle pain was induced by infusion of hypertonic saline into the abductor digiti minimi muscle of 11 healthy men. Intramuscular EMG signals were recorded from the same muscle during four isometric contractions of 60-s duration at 10% of...

The purpose of this study was to assess fatigue and recovery of isotonic power and isometric contractile properties after a series of maximal isotonic contractions. Using a Biodex dynamometer, 13 men [26 yr (SD 3)] performed isotonic [50% of isometric maximal voluntary contraction (MVC) every 1.2 s through 75 degrees range of motion] single-limb knee extensions at the fastest velocity they coul...

Surface electromyographic activity (sEMG) of the biceps brachii (BB) during weak elbow flexion has been reported to immediately increase after strong even while exerting consistent force; this phenomenon is called “post-contraction potentiation” (PCP). To determine whether central nervous system involved in PCP, we investigated effect transcranial direct current stimulation (tDCS) and magnetic ...

The assessment of musculo-articular stiffness (MAS) with the free-oscillation technique is a popular method with a variety of applications. This study examined the sources of variability (load applied and frequency of oscillation) when MAS is assessed. Over two testing occasions, 14 healthy men (27.7±5.2 yr, 1.82±0.04 m, 79.5±8.4 kg) were measured for isometric maximum voluntary contraction and...