Intramuscular fluid pressure during isometric contraction of human skeletal muscle

Abstract

Intramuscular fluid pressures were recorded in the vastus medialis of seven healthy male volunteers. Pressures were measured simultaneously at three different sites in the muscle by a catheter-tip transducer with extremely low volume-displacement characteristics and by two extracorporeal transducers connected to slit catheters. All three recording systems gave qualitatively similar results provided the catheters had inner diameters exceeding 0.53 mm and allowed measurement of pressures lasting as short as 1 s. Wick catheters yielded slower responses than slit catheters. At any position intramuscular fluid pressure increased linearly with force up to maximal voluntary contraction (MVC). However, slopes of these curves varied greatly mainly because the pressure was also a linear function of the distance from the fascia. The highest recorded pressure was 570 Torr. At prolonged submaximal contractions intramuscular fluid pressure oscillated independent of contraction force. The linearity of both the pressure-force relationship and the pressure-depth relationship is compatible with a simple model based on the law of Laplace because the muscle fibers are curved during contraction in this muscle. It is hypothesized that blood flow is first compromised deep in the muscle where pressure is highest and in general at lower stress or tension in short bulging muscles with great curvature of the fibers compared with long slender ones.

Intramuscular pressure, tissue oxygenation and EMG fatigue measured during isometric fatigue-inducing contraction of the multifidus muscle

“…IMP values as high as 500 mmHg are generated during normal vigorous skeletal muscle contraction [34]. This increase in IMP is expected to be the most relevant pathophysiologic factor compromising the blood perfusion of tissue [14].…”

Free radical scavengers are more effective than indomethacin in the prevention of experimentally induced heterotopic ossification

“…[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] Ischemia/Reperfusion Syndrome An isometric muscle contraction accompanied by an elevation of muscular pressure, consequent upon vascular occlusion, can induce a state of relative ischemia in an extremity. Such elevations compress and may even occlude the arteries if the pressure becomes fairly high.…”

“…Moreover, intramuscular pressure and the associated degree of blood flow occlusion increase linearly with an increasing intensity of contraction. [19][20][21][22][23][24][25][26][27] It can be postulated that muscular hypertonia, spasticity, and contractures induce a state of relative ischemia.…”

Muscle Blood Flow and Oxygen Utilization Measured by Near-Infrared Spectroscopy during Handgrip Exercise in Chronic Respiratory Patients

“…It is d e c i d e d b y b a l a n c i n g b e t w e e n s y m p a t r i c vasoconstrictor and vasodilator activation with metabolic product and blood flow dependence. B l o o d f l o w a l s o d e p e n d s o n m e c h a n i c a l compression of the blood vessel by muscle contraction 47) , and the blood flow required by active muscles is remarkably different in the contraction phase compared to the relaxed one 48) . It becomes greatest during 25-45%MVC rhythmic handgrip exercise, and at greater intensities, no blood flow increases are seen 49) .…”