Effects of muscle perfusion pressure on fatigue and systemic arterial pressure in human subjects

1999 ◽  
Vol 86 (3) ◽  
pp. 845-851 ◽  
Author(s):  
Julie R. Wright ◽  
D. I. McCloskey ◽  
Richard C. Fitzpatrick
Keyword(s):  
Blood Pressure ◽  
Perfusion Pressure ◽  
Human Subjects ◽  
Normal Subjects ◽  
Voluntary Contraction ◽  
Muscle Performance ◽  
Central Blood Pressure ◽  
Human Hand ◽  
Adductor Pollicis Muscle ◽  
Arterial Perfusion

The effects of changes in arterial perfusion across the physiological range on the fatigue of a working human hand muscle were studied in seven normal subjects. With the hand above heart level, subjects made repeated isometric contractions of the adductor pollicis muscle at 50% of maximal voluntary contraction in a 6-s on, 4-s off cycle. To assess fatigue, a maximal isometric twitch was elicited in each “off” period by electrical stimulation of the ulnar nerve. The experiment was repeated at least 2 days later with the hand at heart level. Five subjects showed faster fatigue with the arm elevated, and two subjects showed little difference in fatigue for the two conditions. Central blood pressure rose in proportion to fatigue for the subjects overall and returned quickly to its initial level afterwards. We conclude that human muscle fatigue can be increased by physiological reductions in perfusion pressure. Central blood pressure increases as the muscle fatigues, a response that may partially offset declining muscle performance.

Effects of systemic arterial blood pressure on the contractile force of a human hand muscle

2000 ◽  
Vol 88 (4) ◽  
pp. 1390-1396 ◽  
Author(s):  
Julie R. Wright ◽  
D. I. McCloskey ◽  
Richard C. Fitzpatrick
Keyword(s):  
Blood Pressure ◽  
Muscular Activity ◽  
Systemic Blood Pressure ◽  
Muscle Performance ◽  
Knee Extensors ◽  
Human Hand ◽  
Physiological Changes ◽  
Force Output ◽  
Systemic Blood ◽  
Arterial Blood

The effect of physiological changes in systemic blood pressure on the force output of working abductor pollicis (AP) muscle was studied in six normal subjects. Supramaximal tetanic stimulation at the ulnar nerve produced repeated isometric contractions at 1-s intervals. Force output declined gradually with time. During the train of contractions, subjects voluntarily contracted the knee extensors for 1 min; this raised systemic blood pressure by 29%. Force output from AP rose in parallel with blood pressure so that 18% of the contraction force lost through fatigue was recovered for each 10% increase in blood pressure. When blood pressure in the hand was kept constant despite the increased systemic pressure, force output did not rise. The results show that muscle performance is strongly affected by physiological changes in central blood pressure and suggest that sensory input concerning the adequacy of muscle performance exerts a feedback control over the increase in systemic blood pressure during muscular activity.

Effect of altered arterial perfusion pressure on vascular conductance and muscle blood flow dynamic response during exercise in humans

2013 ◽  
Vol 114 (5) ◽  
pp. 620-627 ◽  
Author(s):  
Rodrigo Villar ◽  
Richard L. Hughson
Keyword(s):  
Blood Flow ◽  
Power Output ◽  
Perfusion Pressure ◽  
Body Position ◽  
Muscle Blood Flow ◽  
Plantar Flexion ◽  
Voluntary Contraction ◽  
Vascular Conductance ◽  
Arterial Perfusion ◽  
Three Body

Changes in vascular conductance (VC) are required to counter changes in muscle perfusion pressure (MPP) to maintain muscle blood flow (MBF) during exercise. We investigated the recruitment of VC as a function of peak VC measured in three body positions at two different work rates to test the hypothesis that adaptations in VC compensated changes in MPP at low-power output (LPO), but not at high-power output (HPO). Eleven healthy volunteers exercised at LPO and HPO (repeated plantar flexion contractions at 20–30% maximal voluntary contraction, respectively) in horizontal (HOR), 35° head-down tilt (HDT), and 45° head-up tilt (HUT). Muscle blood flow velocity and popliteal diameter were measured by ultrasound to determine MBF, and VC was estimated by dividing MBF flow by MPP. Peak VC was unaffected by body position. The rates of increase in MBF and VC were significantly faster in HUT and slower in HDT than HOR, and rates were faster in LPO than HPO. During LPO exercise, the increase in, and steady-state values of, MBF were less for HUT and HDT than HOR; the increase in VC was less in HUT than HOR and HDT. During HPO exercise, MBF in the HDT was reduced compared with HOR and HUT, even though VC reached 92% VC peak, which was greater than HOR, which was, in turn, greater than HUT. Reduced MBF during HPO HDT exercise had the functional consequence of a significant increase in muscle electromyographic index, revealing the effects of MPP on O2 delivery during exercise.

Effects of blood pressure on force production in cat and human muscle

1987 ◽  
Vol 63 (2) ◽  
pp. 834-839 ◽  
Author(s):  
S. F. Hobbs ◽  
D. I. McCloskey
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Arterial Pressure ◽  
Perfusion Pressure ◽  
Human Subjects ◽  
Muscle Fibers ◽  
Force Production ◽  
Human Muscle ◽  
Medial Gastrocnemius ◽  
Active Muscle

In anesthetized cats reducing local arterial pressure from 125 to 75 Torr decreased blood flow (53 +/- 5%) and force production (57 +/- 7%) in soleus and medial gastrocnemius. Force was produced in these muscles by aerobic, slowly fatiguing fibers. Similar reductions in arterial pressure did not affect force production in caudofemoralis, which contains mainly fast-fatiguing fibers. In human subjects the electromyogram produced by the ankle extensors during rhythmic constant-force contractions increased as the contracting muscles were raised above the heart during legs-up tilt. This suggests that force production of active muscle fibers at a given level of activation fell with muscle perfusion pressure, thus requiring augmentation of muscle activity to sustain the standard contractions. Because aerobic fibers contributed to these contractions, it appears that force production of human muscle fibers is sensitive to small changes in perfusion pressure and, presumably, blood flow. The critical dependence of developed muscular force on blood pressure is of importance to motor control and may also play a significant role in cardiovascular control during exercise.

Heart Rate Signal Decomposition

2000 ◽  
Vol 39 (02) ◽  
pp. 200-203
Author(s):  
H. Mizuta ◽  
K. Yana
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Pressure Change ◽  
Normal Subjects ◽  
Signal Decomposition ◽  
Large Individual ◽  
Heart Rate Fluctuations ◽  
Type Pattern ◽  
Signal Cancellation ◽  
Pressure Changes

Abstract:This paper proposes a method for decomposing heart rate fluctuations into background, respiratory and blood pressure oriented fluctuations. A signal cancellation scheme using the adaptive RLS algorithm has been introduced for canceling respiration and blood pressure oriented changes in the heart rate fluctuations. The computer simulation confirmed the validity of the proposed method. Then, heart rate fluctuations, instantaneous lung volume and blood pressure changes are simultaneously recorded from eight normal subjects aged 20-24 years. It was shown that after signal decomposition, the power spectrum of the heart rate showed a consistent monotonic 1/fa type pattern. The proposed method enables a clear interpretation of heart rate spectrum removing uncertain large individual variations due to the respiration and blood pressure change.

scholarly journals Assessment of muscle activity using electrical stimulation and mechanomyography: a systematic review

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Raphael Uwamahoro ◽  
Kenneth Sundaraj ◽  
Indra Devi Subramaniam
Keyword(s):  
Electrical Stimulation ◽  
Processing Speed ◽  
Muscle Activity ◽  
Neuromuscular Electrical Stimulation ◽  
Voluntary Contraction ◽  
Electrical Signal ◽  
Muscle Performance ◽  
Inclusion Criteria ◽  
Activity Assessment ◽  
Experimental Protocols

AbstractThis research has proved that mechanomyographic (MMG) signals can be used for evaluating muscle performance. Stimulation of the lost physiological functions of a muscle using an electrical signal has been determined crucial in clinical and experimental settings in which voluntary contraction fails in stimulating specific muscles. Previous studies have already indicated that characterizing contractile properties of muscles using MMG through neuromuscular electrical stimulation (NMES) showed excellent reliability. Thus, this review highlights the use of MMG signals on evaluating skeletal muscles under electrical stimulation. In total, 336 original articles were identified from the Scopus and SpringerLink electronic databases using search keywords for studies published between 2000 and 2020, and their eligibility for inclusion in this review has been screened using various inclusion criteria. After screening, 62 studies remained for analysis, with two additional articles from the bibliography, were categorized into the following: (1) fatigue, (2) torque, (3) force, (4) stiffness, (5) electrode development, (6) reliability of MMG and NMES approaches, and (7) validation of these techniques in clinical monitoring. This review has found that MMG through NMES provides feature factors for muscle activity assessment, highlighting standardized electromyostimulation and MMG parameters from different experimental protocols. Despite the evidence of mathematical computations in quantifying MMG along with NMES, the requirement of the processing speed, and fluctuation of MMG signals influence the technique to be prone to errors. Interestingly, although this review does not focus on machine learning, there are only few studies that have adopted it as an alternative to statistical analysis in the assessment of muscle fatigue, torque, and force. The results confirm the need for further investigation on the use of sophisticated computations of features of MMG signals from electrically stimulated muscles in muscle function assessment and assistive technology such as prosthetics control.

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