The Consequences of Short-Range Stiffness and Fluctuating Muscle Activity for Proprioception of Postural Joint Rotations: The Relevance to Human Standing

2009 ◽  
Vol 102 (1) ◽  
pp. 460-474 ◽  
Author(s):  
Ian D. Loram ◽  
Martin Lakie ◽  
Irene Di Giulio ◽  
Constantinos N. Maganaris
Keyword(s):  
Muscle Activity ◽  
Short Range ◽  
Dead Zone ◽  
Muscle Stiffness ◽  
Joint Rotation ◽  
Basic Principles ◽  
Active Length ◽  
Proprioceptive Signal ◽  
Load Stability ◽  
Tendon Compliance

Proprioception comes from muscles and tendons. Tendon compliance, muscle stiffness, and fluctuating activity complicate transduction of joint rotation to a proprioceptive signal. These problems are acute in postural regulation because of tiny joint rotations and substantial short-range muscle stiffness. When studying locomotion or perturbed balance these problems are less applicable. We recently measured short-range stiffness in standing and considered the implications for load stability. Here, using an appropriately simplified model we analyze the conversion of joint rotation to spindle input and tendon tension while considering the effect of short-range stiffness, tendon compliance, fluctuating muscle activity, and fusimotor activity. Basic principles determine that when muscle stiffness and tendon compliance are high, fluctuating muscle activity is the greatest factor confounding registration of postural movements, such as ankle rotations during standing. Passive and isoactive muscle, uncomplicated by active length fluctuations, enable much better registration of joint rotation and require fewer spindles. Short-range muscle stiffness is a degrading factor for spindle input and enhancing factor for Golgi input. Constant fusimotor activity does not enhance spindle registration of postural joint rotations in actively modulated muscle: spindle input remains more strongly associated with muscle activity than joint rotation. A hypothesized rigid α–γ linkage could remove this association with activity but would require large numbers of spindles in active postural muscles. Using microneurography, the existence of a rigid α–γ linkage could be identified from the correlation between spindle output and muscle activity. Basic principles predict a proprioceptive “dead zone” in the active agonist muscle that is related to the short-range muscle stiffness.

Separation of active and passive components of short-range stiffness of muscle

1977 ◽  
Vol 232 (1) ◽  
pp. 45-49 ◽  
Author(s):  
D. L. Morgan
Keyword(s):  
Short Range ◽  
Muscle Tension ◽  
Isometric Tension ◽  
Incomplete Fusion ◽  
Low Frequencies ◽  
Passive Components ◽  
Stimulus Rate ◽  
Straight Line ◽  
Wide Range ◽  
Tendon Compliance

The short-range stiffness of smoothly but submaximally contracting isometric soleus muscles of anesthetised cats was measured by applying small fast stretches. The ratio of isometric tension to stiffness was plotted against tension over a wide range of muscle lengths and stimulus rates. The results fitted a straight line well, as predicted from crossbridge theory, showing the stiffness to be a function of tension only, independent of the combination of length and stimulus rate used to generate the tension. The major deviation from this line was attributed to incomplete fusion at low frequencies of stimulation. Values believed to be tendon compliance and crossbridge tension per unit of stiffness were found from the graph, and the tendon compliance correlated with the maximum muscle tension. Shortening the tendon by attaching nearer to the muscle changed the results in a manner consistent with the theory, provided that appropriate precautions were taken against slippage.

scholarly journals The Anticipation of Gravity in Human Ballistic Movement

2021 ◽  
Vol 12 ◽  
Author(s):  
Janice Waldvogel ◽  
Ramona Ritzmann ◽  
Kathrin Freyler ◽  
Michael Helm ◽  
Elena Monti ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Muscle Stiffness ◽  
Ultrasound Images ◽  
Ground Contact ◽  
Mechanical Coupling ◽  
Lower Limb Muscles ◽  
Drop Jumps ◽  
And Performance

Stretch-shortening type actions are characterized by lengthening of the pre-activated muscle-tendon unit (MTU) in the eccentric phase immediately followed by muscle shortening. Under 1 g, pre-activity before and muscle activity after ground contact, scale muscle stiffness, which is crucial for the recoil properties of the MTU in the subsequent push-off. This study aimed to examine the neuro-mechanical coupling of the stretch-shortening cycle in response to gravity levels ranging from 0.1 to 2 g. During parabolic flights, 17 subjects performed drop jumps while electromyography (EMG) of the lower limb muscles was combined with ultrasound images of the gastrocnemius medialis, 2D kinematics and kinetics to depict changes in energy management and performance. Neuro-mechanical coupling in 1 g was characterized by high magnitudes of pre-activity and eccentric muscle activity allowing an isometric muscle behavior during ground contact. EMG during pre-activity and the concentric phase systematically increased from 0.1 to 1 g. Below 1 g the EMG in the eccentric phase was diminished, leading to muscle lengthening and reduced MTU stretches. Kinetic energy at take-off and performance were decreased compared to 1 g. Above 1 g, reduced EMG in the eccentric phase was accompanied by large MTU and muscle stretch, increased joint flexion amplitudes, energy loss and reduced performance. The energy outcome function established by linear mixed model reveals that the central nervous system regulates the extensor muscles phase- and load-specifically. In conclusion, neuro-mechanical coupling appears to be optimized in 1 g. Below 1 g, the energy outcome is compromised by reduced muscle stiffness. Above 1 g, loading progressively induces muscle lengthening, thus facilitating energy dissipation.

Hereditary form of sustained muscle activity of peripheral nerve origin causing generalized myokymia and muscle stiffness

1984 ◽  
Vol 15 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Raymond G. Auger ◽  
Jasper R. Daube ◽  
Manuel R. Gomez ◽  
Edward H. Lambert
Keyword(s):  
Peripheral Nerve ◽  
Muscle Activity ◽  
Muscle Stiffness

Relationship Between Muscle Force and Stiffness in the Whole Mammalian Muscle: A Simulation Study

1995 ◽  
Vol 117 (3) ◽  
pp. 339-342 ◽  
Author(s):  
Jacek Cholewicki ◽  
Stuart M. McGill
Keyword(s):  
Muscle Force ◽  
Muscle Stiffness ◽  
Mammalian Muscle ◽  
Cross Bridge ◽  
Skinned Muscle ◽  
Skinned Muscle Fibers ◽  
Wide Range ◽  
Distribution Moment ◽  
Range Of Values ◽  
Tendon Compliance

Several types of analyses in biomechanics require estimates of both muscle force and stiffness. Simulations were performed using the two-state cross-bridge Bond Distribution-Moment muscle model of Zahalak (1981), together with other parameters for passive elasticity and tendon compliance, to estimate instantaneous stiffness and to compare these estimates with the wide range of values reported in the literature. While the relatively simple cross-bridge theory appears to approximate the stiffness of skinned muscle fibers, the stiffness of a complete muscle-tendon unit become complex and non-linear due to relative changes in muscle-tendon length and interaction with activation and length dependent passive elastic components. It would appear that the variability in muscle stiffness values reported in the literature can be explained with the D-M approach.

scholarly journals Mechanical Responses of a Crustacean Slow Muscle

1983 ◽  
Vol 107 (1) ◽  
pp. 367-383 ◽  
Author(s):  
WILLIAM D. CHAPPLE
Keyword(s):  
Short Range ◽  
Motor Nerve ◽  
Maximum Velocity ◽  
Isometric Tension ◽  
Muscle Stiffness ◽  
Gradual Transition ◽  
Active Muscle ◽  
Cross Bridge ◽  
Reference Length ◽  
Activation Level

1. Mechanical properties of the abdominal ventral superficial muscle of the hermit crab, Pagurus pollicarus, were examined under isometric and iso-velocity conditions. The muscle was activated by stimulating its motor nerve at different frequencies. 2. Length-isometric tension relations were measured. Peak tension, P0, was 0.16–0.2MNm−2 and the sarcomere length of the muscle at the optimum length, L0, was 10.8+1.0 μm. Passive tension was high at L0. Correlated measurements of the operating length of the muscle and L0 indicate that the operating length is at a point on the ascending limb of the length-tension curve approximately 0.77 L0. 3. The relationship between activation level of the muscle and the length-tension relation indicates that the curve is not substantially displaced along the length axis by increasing activation level; increased force is primarily due to an increase in the slope of the ascending limb of the curve. 4. The force-velocity relation was obtained by measuring the force at a reference length during iso-velocity shortening of an active muscle. Hill constants of a/P0 = 0.11 + 0.02 and b = 1.07 = 0.24 mm s−1 were obtained. The maximum velocity of shortening per half sarcomere was approximately 4.2μms−1. 5. Stretch of an active muscle did not produce an abrupt short range yield but a gradual transition between short range and terminal stiffness. This behaviour is shown to be due not to differences in cross bridge stiffness between VSM and other muscle but to a non cross bridge stiffness with a value that is one-fifth that of vertebrate muscle. 6. Such a low stiffness may provide an intrinsic mechanism for simplifying load compensation in the absence of rapid proprioceptive reflexes for the control of muscle stiffness.

scholarly journals Movement history influences pendulum test kinematics in children with spastic cerebral palsy

2020 ◽  
Author(s):  
Willaert Jente ◽  
Kaat Desloovere ◽  
Anja Van Campenhout ◽  
Lena H. Ting ◽  
Friedl De Groote
Keyword(s):  
Cerebral Palsy ◽  
Muscle Activity ◽  
Short Range ◽  
Area Under The Curve ◽  
Rectus Femoris ◽  
Reflex Activity ◽  
Spastic Cerebral Palsy ◽  
Clinical Tests ◽  
Pendulum Test ◽  
Movement History

AbstractThe pendulum test assesses quadriceps spasticity by dropping the lower leg of a relaxed patient from the horizontal position and observing limb movement. The first swing excursion decreases with increasing spasticity severity. Our recent simulation study suggests that the reduced initial swing results from muscle short-range stiffness and its interaction with reflex hyper-excitability. Short-range stiffness emerges from the thixotropic behavior of muscles where fiber stiffness upon stretch increases when the muscle is held isometric. Fiber stiffness might thus be higher during the first swing of the pendulum test than during consecutive swings. In addition, it has recently been suggested that muscle spindle firing reflects fiber force rather than velocity and therefore, reflex activity might depend on fiber stiffness. If this hypothesized mechanism is true, we expect to observe larger first swing excursions and reduced reflex muscle activity when the leg is moved rather than kept isometric before release, especially in patients with increased reflex activity. We performed the pendulum test in 15 children with cerebral palsy (CP) and 15 age-matched typically developing (TD) children in two conditions. In the hold condition, the leg was kept isometric in the extended position before release. In the movement condition, the leg was moved up and down before release to reduce the contribution of short-range stiffness. Knee kinematics and muscle activity were recorded. Moving the leg before release increased first swing excursion (p < 0.001) and this increase was larger in children with CP (21°) than in TD children (8°) (p < 0.005). In addition, pre-movement delayed reflex onset by 87 ms (p < 0.05) and reduced reflex activity as assessed through the area under the curve of rectus femoris electromyography (p < 0.05) in children with CP. The movement history dependence of pendulum kinematics and reflex activity supports our hypothesis that muscle short-range stiffness and its interaction with reflex hyper-excitability contribute to joint hyper-resistance in spastic CP. Our results have implications for standardizing movement history in clinical tests of spasticity and for understanding the role of spasticity in functional movements, where movement history differs from movement history in clinical tests.

A Cinefluorographic Investigation of Repeated Fluent Productions of Stutterers in an Adaptation Procedure

1983 ◽  
Vol 26 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Gerald N. Zimmermann ◽  
J. M. Hanley
Keyword(s):  
Muscle Activity ◽  
Adaptation Effect ◽  
Muscle Stiffness ◽  
Repeated Readings ◽  
Jaw Movements ◽  
Lower Lip ◽  
Tonic Muscle ◽  
Adaptation Procedure ◽  
Target Words

Cinefluorography was used to study three stutterers and two nonstutterers repeating a passage made up of monosyllables. CVC target words of the form/cæt/were embedded in the passage and were analyzed to determine the effects of repeating the passage on velocities, displacements, and durations of movements of the tongue, jaw, and lower lip. Coordination among the articulators was also assessed. The investigation was undertaken to test the hypothesis that decreases in velocities and displacements, increased movement durations, and decreased latency between the onsets of jaw movements and of tongue tip movements would be associated with the repeated readings. The hypothesis was not supported by the results. A post hoe analysis showed that a decrease in the variability, of instantaneous velocities (and by inference a decrease in variation in muscle stiffness) was associated with practice for the three stutterers but not for the nonstutterers. Inferences about the adaptation effect are made related (a} to the stabilization of tonic muscle activity which may be associated with a decrease in arousal, and (b) to the, effects of practice.

Stiffness of cat soleus muscle and tendon during activation of part of muscle

1984 ◽  
Vol 52 (3) ◽  
pp. 459-468 ◽  
Author(s):  
U. Proske ◽  
D. L. Morgan
Keyword(s):  
Soleus Muscle ◽  
Muscle Fibers ◽  
Isometric Tension ◽  
Muscle Stiffness ◽  
Ventral Root ◽  
A Value ◽  
Wide Range ◽  
Whole Muscle ◽  
Tendon Compliance ◽  
Stimulation Of

Experiments have been carried out on the soleus muscle and its tendon in the anesthetized cat. Measurements of isometric tension and muscle stiffness were made during contraction of whole or part of the muscle in response to stimulation of ventral root filaments. In an attempt to determine the distribution of tension in different portions of the tendon during activation of only part of the muscle, the free tendon of insertion was split longitudinally into two halves and a strain gauge attached to each piece. From a large number of measurements, it was found that the mean fraction of tension recorded in one-half of the tendon remained about the same, over a wide range of tensions. However, the scatter of values, which increased as the portion of muscle contracting was reduced, was greater than expected if muscle fibers were randomly distributed throughout the muscle. Measurements of muscle and tendon stiffness were made from length and tension changes during stretch of the actively contracting muscle. Ventral root stimulation that engaged 20% or more of the muscle yielded a value for tendon compliance (0.09 mm/N), which was the same as for stimulating the whole muscle. This result suggested that for contraction of portions as small as 20% of the muscle, fibers were effectively attached to the whole tendon, indicating that tendinous attachments of individual muscle fibers ran independent of one another over only a short distance and were bound together over most of their remaining course. It was concluded that groups of muscle fibers selected by stimulation of ventral root filaments are not entirely randomly distributed throughout the muscle. However, for groups representing larger fractions of the total tension, (greater than 20%) the distribution is uniform enough and the connections between their tendinous attachments firm enough for the force applied by such a group to act through a tendon compliance, which is the same as that seen by the whole muscle.

Changes in wrist muscle activity with forearm posture: implications for the study of sensorimotor transformations

2012 ◽  
Vol 108 (11) ◽  
pp. 2884-2895 ◽  
Author(s):  
Aymar de Rugy ◽  
Rahman Davoodi ◽  
Timothy J. Carroll
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Reference Frames ◽  
Wrist Joint ◽  
Isometric Force ◽  
Joint Space ◽  
Coordinate Frame ◽  
Joint Rotation ◽  
Sensorimotor Transformations ◽  
Direction Of Movement

The primate wrist is an ideal model system for studying the reference frames in which movements are coded within the central nervous system, as a simple rotation of the forearm allows dissociation between extrinsic and body-referenced coordinates. Important information regarding coordinate frame transformations has been obtained using this system, particularly from studies involving extracellular cortical and spinal recordings from monkeys. Because preferred directions of muscle use were reported to rotate by less than half of the joint rotation, the system was considered to dissociate three reference frames: extrinsic (direction of movement in space), muscle (activity of muscles), and joint (angle of the wrist joint). However, given the relatively minor changes in reported muscle biomechanics with human forearm rotation, the reported distinction between joint space and muscle space is surprisingly large. Here, we reassessed patterns of wrist muscle activity with changes in forearm posture in humans, during an isometric force-aiming task with a device that enabled stringent control of the musculoskeletal configuration. Results show that the preferred directions for wrist muscle activation closely follow forearm orientation (i.e., by 88%). Control experiments confirmed this, whether the hand was clamped passively by a device or grasped a handle. Furthermore, the remaining 12% discrepancy between intended changes in wrist orientation and muscle use also occurred for muscle-pulling directions obtained by intramuscular electrical stimulation. The findings prompt reconsideration of data based on the previously reported dissociation between joint space and muscle space and have critical implications for future investigations of sensorimotor transformations and their adaptation using the wrist.

scholarly journals Shoulder scaption is dependent on the behavior of the different partitions of the infraspinatus muscle

2021 ◽  
Author(s):  
Kyosuke Hoshikawa ◽  
Takuma Yuri ◽  
Hugo Giambini ◽  
Yoshiro Kiyoshige
Keyword(s):  
Muscle Contraction ◽  
Shear Wave ◽  
Muscle Activity ◽  
Shear Wave Elastography ◽  
Muscle Stiffness ◽  
Peak Activity ◽  
Anatomical Studies ◽  
Subsequent Decrease ◽  
Infraspinatus Muscle ◽  
The Difference

Abstract Purpose The purpose of this study was to investigate if the three partitions (superior, middle, and inferior partitions) of the infraspinatus muscle previously described in anatomical studies will present different behavior during scapular plane abduction (scaption) as described using shear-wave elastography, especially during initial range of motion. Methods Eight volunteers held their arm against gravity 15° intervals from 30° to 150° in scaption. Shear-wave elastography was implemented at each position to measure shear modulus at rest and during muscle contraction, as a surrogate for muscle stiffness, of each partition. Muscle activity was defined as the difference in stiffness values between the resting positions and those during muscle contraction (ΔE = stiffness at contraction—stiffness at rest). Results The activity value for the middle partition was 25.1 ± 10.8 kPa at 30° and increased up to 105° (52.2 ± 10.8 kPa), with a subsequent decrease at larger angle positions (p < .001). The superior partition showed a flatter and constant behavior with smaller activity values except at higher angles (p < .001). Peak activity values for the superior partition were observed at 135° (23.0 ± 12.0 kPa). Increase activity for inferior partition began at 60° and showed a peak at 135° (p < .001; 32.9 ± 13.8 kPa). Conclusion Stiffness measured using shear-wave elastography in each partition of the infraspinatus muscle demonstrated different behavior between these partitions during scaption. The middle partition generated force throughout scaption, while the superior and inferior partitions exerted force at end range.

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