Muscular mechanisms of snake locomotion: an electromyographic study of the sidewinding and concertina modes of Crotalus cerastes, Nerodia fasciata and Elaphe obsoleta

1988 ◽  
Vol 140 (1) ◽  
pp. 1-33 ◽  
Author(s):  
B. C. Jayne
Keyword(s):  
Muscle Activity ◽  
Body Region ◽  
Longissimus Dorsi ◽  
Lateral Flexion ◽  
Elaphe Obsoleta ◽  
Active Muscle ◽  
Nerodia Fasciata ◽  
Static Contact ◽  
Crotalus Cerastes ◽  
Epaxial Muscles

Synchronized electromyography and cinematography were used to determine the muscle activity of colubroid snakes during sidewinding and concertina locomotion. The primary muscles studied were the three largest, most superficial epaxial muscles: the Mm. semispinalis-spinalis, longissimus dorsi and iliocostalis. Sidewinding locomotion of Nerodia fasciata and Crotalus cerastes was the result of continuous posterior propagation of contractile blocks consisting of several adjacent muscle segments. During sidewinding, the activity of the M. longissimus dorsi and M. iliocostalis was primarily unilateral, beginning when a body region was convex and ending when it was maximally concave on the side of the active muscle. Unilateral activity of the M. semispinalis-spinalis correlated with lateral flexion in addition to bilateral activity that correlated with dorsiflexion of the vertebral column. During concertina locomotion of N. fasciata and Elaphe obsoleta, muscle activity also involved blocks of several simultaneously active adjacent muscle segments, but all major activity was unilateral and was not propagated posteriorly in a simple continuous fashion. Muscle activity during concertina locomotion correlated either with lateral flexion towards the side of the active muscle or with the maintenance of static contact with the sides of a tunnel. The number of simultaneously active adjacent muscle segments and the maximum duration of continuous muscle activity varied significantly between Nerodia and Elaphe and among the different widths of tunnels. Theoretical considerations combined with observed differences suggest that the more elongate body of Elaphe is advantageous for performing concertina locomotion. There was no consistent evidence that nonhomologous muscles with tendinous interconnections functioned as single units during either of these two locomotor modes. Although individual segments of the studied epaxial muscles span several vertebrae, via long, tendinous connections, consistent kinematic correlations with muscle activity were observed only between the contractile portion of a muscle segment and the vertebrae adjacent to that contractile portion.

Changes in muscle activities and kinematics due to simulated leg length inequalities

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hannah Lena Siebers ◽  
Jörg Eschweiler ◽  
Filippo Migliorini ◽  
Valentin Michael Quack ◽  
Markus Tingart ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Rectus Femoris ◽  
Knee Extension ◽  
Pelvic Obliquity ◽  
Lateral Flexion ◽  
Leg Length ◽  
Joint Angles ◽  
Leg Muscles ◽  
Compensation Mechanisms ◽  
Musculoskeletal Problems

Abstract Muscle imbalances are a leading cause of musculoskeletal problems. One example are leg length inequalities (LLIs). This study aimed to analyze the effect of different (simulated) LLIs on back and leg muscles in combination with kinematic compensation mechanics. Therefore, 20 healthy volunteers were analyzed during walking with artificial LLIs (0–4 cm). The effect of different amounts of LLIs and significant differences to the reference condition without LLI were calculated of maximal joint angles, mean muscle activity, and its symmetry index. While walking, LLIs led to higher muscle activity and asymmetry of back muscles, by increased lumbar lateral flexion and pelvic obliquity. The rectus femoris showed higher values, independent of the amount of LLI, whereas the activity of the gastrocnemius on the shorter leg increased. The hip and knee flexion of the long leg increased significantly with increasing LLIs, like the knee extension and the ankle plantarflexion of the shorter leg. The described compensation mechanisms are explained by a dynamic lengthening of the short and shortening of the longer leg, which is associated with increased and asymmetrical muscle activity. Presenting this overview is important for a better understanding of the effects of LLIs to improve diagnostic and therapy in the future.

Epaxial muscle function in trotting dogs

2001 ◽  
Vol 204 (17) ◽  
pp. 3053-3064 ◽  
Author(s):  
Dale A. Ritter ◽  
Peter N. Nassar ◽  
Mathew Fife ◽  
David R. Carrier
Keyword(s):  
Muscle Function ◽  
Longissimus Dorsi ◽  
Ground Reaction Forces ◽  
Lumbar Region ◽  
Terrestrial Vertebrates ◽  
Reaction Forces ◽  
Trunk Kinematics ◽  
Epaxial Muscles ◽  
Epaxial Muscle ◽  
Support Phase

SUMMARY One of the features that distinguish mammals from other groups of terrestrial vertebrates is the structure and relative size of their epaxial muscles. Yet we have only a superficial understanding of the role these muscles play in locomotion. To address their locomotor function, we recorded the electrical activity of the iliocostalis, longissimus dorsi and multifidus muscles of trotting dogs. Activity was monitored at both lumbar and thoracic sites. To develop and evaluate hypotheses of epaxial muscle function, we quantified footfall patterns and sagittal trunk kinematics from high-speed videos, and the magnitude and orientation of ground reaction forces from force-plate recordings. All three epaxial muscles tended to exhibit a double-bursting (biphasic) activity pattern, with the exception of the iliocostalis muscle at the thoracic site (which was uniphasic). In general, a large burst of activity in each muscle occurred during the second half of the support phase of the ipsilateral hindlimb, and was active for an average of 30% of the locomotor cycle. A smaller burst of activity occurred during the second half of the support phase of the contralateral hindlimb, and was active for an average of 15% of the locomotor cycle. Analysis of ground reaction forces and sagittal trunk kinematics led us to the hypothesis that the epaxial muscles do not directly stabilize the trunk against the vertical and horizontal components of the ground reaction force. Instead, the epaxial muscles appear to counteract the tendency of the trunk to rebound (flex) in the sagittal plane during the latter half of the support phase. This hypothesis of epaxial muscle function was supported by loading experiments performed on the longissimus dorsi muscle in the lumbar region.

Pixel T2 distribution in functional magnetic resonance images of muscle

1999 ◽  
Vol 87 (6) ◽  
pp. 2107-2114 ◽  
Author(s):  
Barry M. Prior ◽  
Jeanne M. Foley ◽  
Roop C. Jayaraman ◽  
Ronald A. Meyer
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Muscle Activity ◽  
Random Distribution ◽  
Motor Units ◽  
Magnetic Resonance Images ◽  
Moderate Intensity ◽  
Resonance Imaging ◽  
Active Muscle ◽  
Repetition Maximum

Increases in skeletal muscle 1H-NMR transverse relaxation time (T2) observed by magnetic resonance imaging have been used to map whole muscle activity during exercise. Some studies further suggest that intramuscular variations in T2 after exercise can be used to map activity on a pixel-by-pixel basis by defining an active T2 threshold and counting pixels that exceed the threshold as “active muscle.” This implies that motor units are nonrandomly distributed across the muscle and, therefore, that the distribution of pixel T2 values ought to be substantially broader after moderate exercise than at rest or after more intense exercise, since moderate-intensity exercise should recruit some motor units, and hence some pixels, but not others. This study examined the distribution of pixel T2 values in three muscles (quadriceps, anterior tibialis, and biceps/brachialis) of healthy subjects (5 men and 2 women, 18–46 yr old) at rest, after exercise to fatigue (50% 1 repetition maximum at 20/min to failure = Max), and at ½Max (25% 1 repetition maximum, same number of repetitions as Max). Although for each muscle there was a linear relationship between exercise intensity and mean pixel T2, there was no significant difference in the variance of pixel T2 between ½Max and Max exercise. There was a modest (10–43%) increase in variance of pixel T2 after both exercises compared with rest, but this was consistent with a Monte Carlo simulation of muscle activity that assumed a random distribution of motor unit territories across the muscle and a random distribution of muscle cells within each motor unit's territory. In addition, 40% of the pixel-to-pixel muscle T2 variations were shown to be due to imaging noise. The results indicate that magnetic resonance imaging T2 cannot reliably map active muscle on a pixel-by-pixel basis in normal subjects.

scholarly journals Gravitational and dynamic components of muscle torque underlie tonic and phasic muscle activity during goal-directed reaching

2017 ◽  
Author(s):  
Erienne Olesh ◽  
Bradley Pollard ◽  
Valeriya Gritsenko
Keyword(s):  
Motion Capture ◽  
Muscle Activity ◽  
Neural Control ◽  
Muscle Activation ◽  
Kinetic Properties ◽  
Motion Capture Data ◽  
Active Muscle ◽  
Muscle Torque ◽  
Dynamic Components ◽  
Muscle Torques

AbstractHuman reaching movements require complex muscle activations to produce the forces necessary to move the limb in a controlled manner. How gravity and the complex kinetic properties of the limb contribute to the generation of the muscle activation pattern by the central nervous system (CNS) is a long-standing question in neuroscience. To address this question, muscle activity is often subdivided into static and phasic components. The former is thought to be related to posture maintenance and transitions between postures. The latter represents the remainder of muscle activity and is thought to be related to active movement production and the compensation for the kinetic properties of the limb. In the present study, we directly addressed how this subdivision of muscle activity into static and phasic components is related to the corresponding components of active muscle torques. Eight healthy subjects pointed in virtual reality to visual targets arranged to create a standard center-out reaching task in three dimensions. Muscle activity and motion capture data were synchronously collected during the movements. The motion capture data were used to calculate gravitational and dynamic components of active muscle torques using a dynamic model of the arm with 5 degrees of freedom. Principal Component Analysis (PCA) was then applied to muscle activity and the torque components, separately, to reduce the dimensionality of the data. Muscle activity was also reconstructed from gravitational and dynamic torque components. Results show that the gravitational and dynamic components of muscle torque represent a significant amount of variance in muscle activity. This method could be used to identify static and phasic components of muscle activity using muscle torques. The contribution of both components to the overall muscle activity was largely equal, unlike their relative contribution to active muscle torques, which may reflect a neural control strategy.

scholarly journals Investigation of lower limb’s muscles activity during performance of salat between two age groups

2019 ◽  
Vol 14 (2) ◽  
pp. 608
Author(s):  
N. Abdul Malik ◽  
Z. Wahid ◽  
A. F. Zulkipili ◽  
S. Noorjannah Ibrahim ◽  
T. S. Gunawan ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Age Groups ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Surface Emg ◽  
Active Muscle ◽  
Factors Affecting ◽  
Significant Difference ◽  
Result Show ◽  
Two Age Groups

Muscles play an important role in the movement of limbs. They undergo contraction to straighten or to bend a joint for the limbs to move. There are many factors that can affect muscle activity. Age could be one of the possible factors affecting muscle activity. The purpose of this study was to investigate the lower limb’s muscles activity during performance of <em>salat</em> between two age groups. The lower limb’s muscles investigated were Gastrocnemius (GAS), Biceps Femoris (BF), Tibialis Anterior (TA) and Rectus Femoris (RF). The postures involve are standing, bowing, prostrating and sitting. The electromyography (EMG) signals of the muscles were measured using the technique of surface EMG (sEMG). The signals were acquired by using Delsys Bagnoli™ Desktop sEMG system and EMGworks®. Ten healthy subjects from two age groups were recruited in this study. The first group consists of five males aged between 20 to 29 while the second group consists of five males aged above 40. The raw EMG signals acquired were analyzed and the EMG envelopes were developed using MATLAB. The averaged RMS values of EMG for each muscle were also calculated. Analysis of variance (ANOVA) of the EMGs was obtained by using <em>F</em>-test. Further investigation of the variance was performed by using Tukey comparison. From the results, the most active muscle during the performance of <em>salat</em> is BF while the less active muscle is GAS for both age groups. The statistical result show that there is no difference in the muscle activity pattern between the two age groups but there is significant difference among the muscles investigated.

Axial muscle function during lizard locomotion

1996 ◽  
Vol 199 (11) ◽  
pp. 2499-2510 ◽  
Author(s):  
D Ritter
Keyword(s):  
Muscle Activity ◽  
Lateral Bending ◽  
Lizard Species ◽  
Iguana Iguana ◽  
Kinematic Data ◽  
Basal Clade ◽  
Varanus Salvator ◽  
Epaxial Muscles ◽  
Primary Lateral ◽  
Epaxial Muscle

It was recently reported that the epaxial muscles of a lizard, Varanus salvator, function to stabilize the trunk during locomotion, and it was suggested that this stabilizing role may be a shared derived feature of amniotes. This result was unexpected because it had previously been assumed that the epaxial muscles of lizards function to produce lateral bending during locomotion and that only in mammals and birds were the epaxial muscles active in stabilizing the trunk. These results and the inferences made from them lead to two questions. (1) Is the pattern of epaxial muscle activity observed in V. salvator representative of a basal lizard condition or is it a derived condition that evolved within lizards? (2) If the epaxial muscles do not produce lateral bending, which muscles do carry out this function? These questions were addressed by collecting synchronous electromyographic (EMG) and kinematic data from two lizard species during walking and running. EMG data were collected from the epaxial muscles of a lizard species from a basal clade, Iguana iguana, in order to address the first question. EMG data were collected from the hypaxial muscles of both Iguana iguana and Varanus salvator to address the second question. The timing of epaxial muscle activity in Iguana iguana relative to the kinematics of limb support and lateral trunk bending is similar to that observed in Varanus salvator, a finding that supports the hypothesis that the epaxial muscles stabilize the trunk during locomotion in lizards and that this stabilizing role is a basal feature of lizards. Therefore, a stabilizing function of the epaxial muscles is most parsimoniously interpreted as a basal amniote feature. In both Iguana iguana and Varanus salvator, the activity of two of the hypaxial muscles, the external oblique and rectus abdominis, is appropriately timed for the production of lateral bending. This indicates that elements of the hypaxial musculature, not the epaxial musculature, are the primary lateral bending muscles of lizards.

scholarly journals Side-Impact Collision: Mechanics of Obstacle Negotiation in Sidewinding Snakes

2020 ◽  
Author(s):  
Henry C. Astley ◽  
Jennifer M. Rieser ◽  
Abdul Kaba ◽  
Veronica M. Paez ◽  
Ian Tomkinson ◽  
...  
Keyword(s):  
Natural Habitat ◽  
Body Waves ◽  
Side Impact ◽  
Behavioral Strategies ◽  
Cluttered Environments ◽  
Heterogeneous Habitats ◽  
Static Contact ◽  
Lateral Undulation ◽  
Crotalus Cerastes ◽  
And Control

AbstractSnakes excel at moving through cluttered environments, and heterogeneities can be used as propulsive contacts for snakes performing lateral undulation. However, sidewinding, often associated with sandy deserts, cuts a broad path through the environment that may increase the vulnerability to obstacles. Our prior work demonstrated that sidewinding can be represented as a pair of orthogonal body waves (vertical and horizontal) that can be independently modulated to achieve high maneuverability and incline ascent, suggesting that sidewinders may also use template modulations to negotiate obstacles. To test this hypothesis, we recorded overhead video of four sidewinder rattlesnakes (Crotalus cerastes) crossing a line of vertical pegs placed in the substrate. Snakes used three methods to traverse the obstacles: a Propagate Through behavior in which the lifted moving portion of the snake was deformed around the peg and dragged through as the snake continued sidewinding (115/160 runs), Reversal turns that reorient the snake entirely (35/160), or switching to Concertina locomotion (10/160). The Propagate-Through response was only used if the anterior-most region of static contact would propagate along a path anterior to the peg, or if a new region of static contact could be formed near the head to satisfy this condition; otherwise, snakes could only use Reversal Turns or switch to Concertina locomotion. Reversal Turns allowed the snake to re-orient and either escape without further peg contact or resorting to Propagate Through. We developed an algorithm to reproduce the Propagate Through behavior in a robotic model using a modulation of the two-wave template. This range of behavioral strategies provides sidewinders with a versatile range of options for effectively negotiating obstacles in their natural habitat, as well as provide insights into the design and control of robotic systems dealing with heterogeneous habitats.

scholarly journals Asymmetrical Muscle Activity During Feeding in the Gar, Lepisosteus Oculatus

1980 ◽  
Vol 84 (1) ◽  
pp. 17-32
Author(s):  
G. V. LAUDER ◽  
S. M. NORTON
Keyword(s):  
Muscle Activity ◽  
High Speed ◽  
Prey Capture ◽  
Activity Patterns ◽  
Head Movements ◽  
Spotted Gar ◽  
High Speed Cinematography ◽  
The Right ◽  
Epaxial Muscles ◽  
Lepisosteus Oculatus

Prey capture in the spotted gar, Lepisosteus oculatus, was studied by high-speed cinematography synchronized with electromyographic recordings of cranial muscle activity. Muscle activity patterns were recorded during each of the three major phases of feeding: the initial strike at the prey, manipulation of the prey following capture, and swallowing. With one exception, the obliquus superioris, all muscles at the strike are active in a bilaterally symmetrical pattern. During the manipulation phase two distinct muscle activity patterns occur: one is characterized by symmetrical activity in the epaxial muscles and obliquus inferioris, the other by complete asymmetry between the right and left sternohyoideus, obliquus superioris, and epaxial muscles. Low-amplitude manipulatory movements are characterized by activity in one side of the sternohyoideus only, all other muscles being generally inactive. The adductor mandibulae and obliquus inferioris are always active symmetrically. Asymmetrical activity in the sternohyoideus, epaxial muscles, and obliquus superioris correlates with lateral head movements during feeding and acts to rotate prey into the preferred orientation for swallowing. The pattern of asymmetrical activity between right and left side muscles is discussed in relation to previous studies of feeding which utilized only unilateral muscle recordings.

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