Sjøgaard, Gisela, Bente R. Jensen, Alan R. Hargens, and Karen Søgaard. Intramuscular pressure and EMG relate during static contractions but dissociate with movement and fatigue. J Appl Physiol 96: 1522–1529, 2004. First published December 5, 2003; 10.1152/ japplphysiol.00687.2003.—Intramuscular pressure (IMP) and electromyography (EMG) mirror muscle force in the nonfatigued muscle during static...

Pelvic muscle contractions during sexual response can be monitored conveniently by the anal probe method described. Eleven young adult male subjects were each recorded for three sessions of masturbation to orgasm. Electrical signals from an anal pressure probe were automatically digitized by computer. Orgasmic contractions were easily distinguished from voluntary contractions by the steadily in...

INTRODUCTION Losses in muscle mass and strength may affect an astronaut's safety; therefore, it is of utmost importance to optimize countermeasures to minimize atrophy and strength loss during spaceflight. The main purpose of this study was to determine if high force eccentric or isometric contractions performed by the plantar flexor group during hind limb suspension would preserve muscle mass ...

33 We analyzed individual motor units during electrically-elicited cramp contractions with 34 the aim of characterizing the variability and degree of common oscillations in their discharges. 35 Intramuscular and surface EMG signals were detected from the abductor hallucis muscle of 11 36 healthy subjects (age 27.0 ± 3.7 yrs) during electrically-elicited cramps. In total, 48 motor units 37 were ...

Pilegaard, Henriette, and Sven Asp. Effect of prior eccentric contractions on lactate/H1 transport in rat skeletal muscle. Am. J. Physiol. 274 (Endocrinol. Metab. 37): E554– E559, 1998.—The effect of prior eccentric contractions on skeletal muscle lactate/H1 transport was investigated in rats. Lactate transport was measured in sarcolemmal giant vesicles obtained from soleus and red (RG) and whi...

The time course of muscle fiber conduction velocity and surface myoelectric signal spectral (mean and median frequency of the power spectrum) and amplitude (average rectified and root-mean-square value) parameters was studied in 20 experiments on the tibialis anterior muscle of 10 healthy human subjects during sustained isometric voluntary or electrically elicited contractions. Voluntary contra...

It is commonly accepted that skeletal muscles from dystrophin-deficient mdx mice are more susceptible than those from wild-type mice to damage from eccentric contractions. However, the downstream mechanisms involved in this enhanced force drop remain controversial. We studied the reduction of contractile force induced by eccentric contractions elicited in vivo in the gastrocnemius muscle of wil...

Subjecting a muscle to a series of eccentric contractions in which the contracting muscle is lengthened results in a number of changes in its mechanical properties. These include a fall in isometric tension that is particularly pronounced during low-frequency stimulation, a phenomenon known as low-frequency depression (LFD). Reports of LFD have not taken into account the shift in optimum length...

An important assumption in 2D numerical models of skeletal muscle contraction involves deformation in the third dimension of the included muscle section. The present paper studies the often used plane strain description. Therefore, 3D muscle surface deformation is measured from marker displacements during isometric contractions at various muscle lengths. Longitudinal strains at superficial musc...

The central nervous system employs different strategies to execute specific motor tasks. Because afferent feedback during shortening and lengthening muscle contractions differs, the neural strategy underlying these tasks may be quite distinct. Cortical drive may be adjusted or afferent input regulated. The exact mechanisms are not clear. Here, we examine the control of synaptic transmission acr...