scholarly journals The effects of experimental muscle and skin pain on the static stretch sensitivity of human muscle spindles in relaxed leg muscles

2008 ◽  
Vol 586 (11) ◽  
pp. 2713-2723 ◽  
Author(s):  
Ingvars Birznieks ◽  
Alexander R. Burton ◽  
Vaughan G. Macefield
Keyword(s):  
Muscle Spindles ◽  
Human Muscle ◽  
Static Stretch ◽  
Leg Muscles ◽  
Skin Pain ◽  
Stretch Sensitivity

Lower Limb Human Muscle Enhancer

2001 ◽  
Author(s):  
Joseph J. Misuraca ◽  
Constantinos Mavroidis
Keyword(s):  
Lower Limb ◽  
Weight Bearing ◽  
Kinematic Chain ◽  
Human Muscle ◽  
The Body ◽  
Knee Joints ◽  
Lower Body ◽  
Loop Control ◽  
Test Fixture ◽  
Leg Muscles

Abstract This paper describes the design, control, and testing of a Human Muscle Enhancer (HME) system that will augment the muscle capabilities of subjects requiring partial lower-limb weight-bearing gait support. The HME described in this paper is a pneumatically actuated quick connecting exoskeleton system that attaches to the foot and hip area of the body, thus “closing” the lower body kinematic chain. Control of the system is achieved by using encoders at the knee joints and Myo-Pneumatic (MP) Sensors implanted into the shoes and outer garments of the human. To test this design concept, a lower body exoskeleton test fixture has been fabricated. The test fixture mimics the human leg with the top cylinder providing the body weight on the leg. Another cylinder acts as leg muscles to provide the adjustable human reaction of the leg. Preliminary open and closed loop control tests have been performed that demonstate the capability of controlling the HME using the MP sensors.

Complexity-Based Analysis of the Relation between Human Muscle Reaction and Walking Path

2020 ◽  
Vol 19 (03) ◽  
pp. 2050025 ◽  
Author(s):  
Shahul Mujib Kamal ◽  
Sue Sim ◽  
Rui Tee ◽  
Visvamba Nathan ◽  
Hamidreza Namazi
Keyword(s):  
Fractal Dimension ◽  
Statistical Analysis ◽  
Fractal Theory ◽  
Contact Point ◽  
Fractal Dimensions ◽  
Human Muscle ◽  
Physiological Signals ◽  
Eeg Signal ◽  
Leg Muscles ◽  
Emg Signal

Legs are the contact point of humans during walking. In fact, leg muscles react when we walk in different conditions (such as different speeds and paths). In this research, we analyze how walking path affects leg muscles’ reaction. In fact, we investigate how the complexity of muscle reaction is related to the complexity of path of movement. For this purpose, we employ fractal theory. In the experiment, subjects walk on different paths that have different fractal dimensions and then we calculate the fractal dimension of Electromyography (EMG) signals obtained from both legs. The result of our analysis showed that the complexity of EMG signal increases with the increment of complexity of path of movement. The conducted statistical analysis also supported the result of analysis. The method of analysis used in this research can be further applied to find the relation between complexity of path of movement and other physiological signals of humans such as respiration and Electroencephalography (EEG) signal.

scholarly journals Effects of tonic muscle pain on fusimotor control of human muscle spindles during isometric ankle dorsiflexion

2019 ◽  
Vol 121 (4) ◽  
pp. 1143-1149
Author(s):  
Lyndon J. Smith ◽  
Vaughan G. Macefield ◽  
Ingvars Birznieks ◽  
Alexander R. Burton
Keyword(s):  
Muscle Spindle ◽  
Muscle Pain ◽  
Tibialis Anterior Muscle ◽  
Muscle Spindles ◽  
Muscle Spindle Afferents ◽  
Firing Rates ◽  
Leg Muscles ◽  
Tonic Muscle ◽  
Voluntary Contractions ◽  
Ankle Dorsiflexors

Studies on anesthetized animals have revealed that nociceptors can excite fusimotor neurons and thereby change the sensitivity of muscle spindles to stretch; such nociceptive reflexes have been suggested to underlie the mechanisms that lead to chronic musculoskeletal pain syndromes. However, the validity of the “vicious cycle” hypothesis in humans has yielded results contrasting with those found in animals. Given that spindle firing rates are much lower in humans than in animals, it is possible that some of the discrepancies between human experimental data and those obtained in animals could be explained by differences in background fusimotor drive when the leg muscles are relaxed. We examined the effects of tonic muscle pain during voluntary contractions of the ankle dorsiflexors. Unitary recordings were obtained from 10 fusimotor-driven muscle spindle afferents (6 primary, 4 secondary) supplying the ankle dorsiflexors via a microelectrode inserted percutaneously into the common peroneal nerve. A series of 1-min weak contractions was performed at rest and during 1 h of muscle pain induced by intramuscular infusion of 5% hypertonic saline into the tibialis anterior muscle. We did not observe any statistically significant increases in muscle spindle firing rates of six afferents followed during tonic muscle pain, although discharge variability increased slightly. Furthermore, a participant’s capacity to maintain a constant level of force, while relying on proprioceptive feedback in the absence of visual feedback, was not compromised during pain. We conclude that nociceptive inputs from contracting muscle do not excite fusimotor neurons during voluntary isometric contractions in humans. NEW & NOTEWORTHY Data obtained in the cat have shown that muscle pain causes a marked increase in the firing of muscle spindles, attributed to a nociceptor-driven fusimotor reflex. However, our studies of muscle spindles in relaxed leg muscles failed to find any effect on spindle discharge. Here we showed that experimental muscle pain failed to increase the firing of muscle spindle afferents during weak voluntary contractions, when fusimotor drive sufficient to increase their firing is present.

Information-based analysis of the relation between human muscle reaction and walking path

2020 ◽  
Vol 28 (6) ◽  
pp. 675-684 ◽  
Author(s):  
Shahul Mujib Kamal ◽  
Norazryana Binti Mat Dawi ◽  
Sue Sim ◽  
Rui Tee ◽  
Visvamba Nathan ◽  
...  
Keyword(s):  
Nervous System ◽  
Information Content ◽  
Muscle Activity ◽  
Human Muscle ◽  
Complex Structures ◽  
Entropy Analysis ◽  
Movement Path ◽  
Leg Muscles ◽  
Emg Signal ◽  
Leg Muscle

BACKGROUND: Walking is one of the important actions of the human body. For this purpose, the human brain communicates with leg muscles through the nervous system. Based on the walking path, leg muscles act differently. Therefore, there should be a relation between the activity of leg muscles and the path of movement. OBJECTIVE: In order to address this issue, we analyzed how leg muscle activity is related to the variations of the path of movement. METHOD: Since the electromyography (EMG) signal is a feature of muscle activity and the movement path has complex structures, we used entropy analysis in order to link their structures. The Shannon entropy of EMG signal and walking path are computed to relate their information content. RESULTS: Based on the obtained results, walking on a path with greater information content causes greater information content in the EMG signal which is supported by statistical analysis results. This allowed us to analyze the relation between muscle activity and walking path. CONCLUSION: The method of analysis employed in this research can be applied to investigate the relation between brain or heart reactions and walking path.

scholarly journals Human Muscle Spindles Act as Forward Sensory Models

2010 ◽  
Vol 20 (19) ◽  
pp. 1763-1767 ◽  
Author(s):  
Michael Dimitriou ◽  
Benoni B. Edin
Keyword(s):  
Muscle Spindles ◽  
Human Muscle

scholarly journals Functional properties of human muscle spindles

2018 ◽  
Vol 120 (2) ◽  
pp. 452-467 ◽  
Author(s):  
Vaughan G. Macefield ◽  
Thomas P. Knellwolf
Keyword(s):  
Functional Properties ◽  
Somatosensory System ◽  
Muscle Length ◽  
Muscle Spindles ◽  
Human Muscle ◽  
Independent Control ◽  
Fascicle Length ◽  
Muscle Fascicle ◽  
The Central Nervous System ◽  
Human Muscles

Muscle spindles are ubiquitous encapsulated mechanoreceptors found in most mammalian muscles. There are two types of endings, primary and secondary, and both are sensitive to changes in muscle length and velocity, with the primary endings having a greater dynamic sensitivity. Unlike other mechanoreceptors in the somatosensory system, muscle spindles are unique in possessing motor innervation, via γ-motoneurons (fusimotor neurons), that control their sensitivity to stretch. Much of what we know about human muscles spindles comes from studying the behavior of their afferents via intraneural microelectrodes (microneurography) inserted into accessible peripheral nerves. We review the functional properties of human muscle spindles, comparing and contrasting with what we know about the functions of muscle spindles studied in experimental animals. As in the cat, many human muscle spindles possess a background discharge that is related to the degree of muscle stretch, but mean firing rates are much lower (~10 Hz). They can faithfully encode changes in muscle fascicle length in passive conditions, but higher level extraction of information is required by the central nervous system to measure changes in muscle length during muscle contraction. Moreover, although there is some evidence supporting independent control of human muscle spindles via fusimotor neurons, any effects are modest compared with the clearly independent control of fusimotor neurons observed in the cat.

Dual response from human muscle spindles in fast voluntary movements

1991 ◽  
Vol 141 (3) ◽  
pp. 363-371 ◽  
Author(s):  
N. A. AL-FALAHE ◽  
M. NAGAOKA ◽  
A. B. VALLBO
Keyword(s):  
Muscle Spindles ◽  
Human Muscle ◽  
Voluntary Movements ◽  
Dual Response

Innervation of normal human muscle spindles

Neurology ◽  
1970 ◽  
Vol 20 (5) ◽  
pp. 463-463 ◽  
Author(s):  
W. R. Kennedy
Keyword(s):  
Muscle Spindles ◽  
Human Muscle ◽  
Normal Human

scholarly journals Sympathetic innervation of human muscle spindles

2015 ◽  
Vol 226 (6) ◽  
pp. 542-548 ◽  
Author(s):  
Dina Radovanovic ◽  
Kevin Peikert ◽  
Mona Lindström ◽  
Fatima Pedrosa Domellöf
Keyword(s):  
Sympathetic Innervation ◽  
Muscle Spindles ◽  
Human Muscle
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