COMMON AND DISTINCT MUSCLE SYNERGIES DURING LEVEL AND SLOPE LOCOMOTION IN THE CAT

2021 ◽  
Author(s):  
Alexander N Klishko ◽  
Adil Akyildiz ◽  
Ricky Mehta ◽  
Boris I. Prilutsky
Keyword(s):  
Stance Phase ◽  
Rectus Femoris ◽  
Emg Activity ◽  
Modular Organization ◽  
Muscle Synergies ◽  
Cycle Duration ◽  
Hindlimb Muscles ◽  
Level Walking ◽  
Adult Cats ◽  
Activity Cluster

Although it is well established that the motor control system is modular, the organization of muscle synergies during locomotion and their change with ground slope are not completely understood. For example, typical reciprocal flexor-extensor muscle synergies of level walking in cats break down in downslope: one-joint hip extensors are silent throughout the stride cycle, whereas hindlimb flexors demonstrate an additional stance phase-related EMG burst (Smith et al. 1998a). Here we investigated muscle synergies during Level, Upslope (27o) and Downslope (-27o) walking in adult cats to examine common and distinct features of modular organization of locomotor EMG activity. Cluster analysis of EMG burst onset-offset times of 12 hindlimb muscles revealed 5 flexor and extensor burst groups that were generally shared across slopes. Stance-related bursts of flexor muscles in downslope were placed in a burst group from Level and Upslope walking formed by the rectus femoris. Walking Upslope changed swing/stance phase durations of Level walking but not the cycle duration. Five muscle synergies computed using non-negative matrix factorization accounted for at least 95% of variance in EMG patterns in each slope. Five synergies were shared between Level and Upslope walking, whereas only 3 of those were shared with Downslope synergies; these synergies were active during the swing phase and phase transitions. Two stance-related synergies of downslope walking were distinct; they comprised a mixture of flexors and extensors. We suggest that the modular organization of muscle activity during Level and Slope walking results from interactions between motion-related sensory feedback, CPG, and supraspinal inputs.

Forms of Forward Quadrupedal Locomotion. II. A Comparison of Posture, Hindlimb Kinematics, and Motor Patterns for Upslope and Level Walking

1998 ◽  
Vol 79 (4) ◽  
pp. 1687-1701 ◽  
Author(s):  
Patricia Carlson-Kuhta ◽  
Tamara V. Trank ◽  
Judith L. Smith
Keyword(s):  
Stance Phase ◽  
Emg Activity ◽  
Similar Data ◽  
Flexor Muscle ◽  
Motor Patterns ◽  
Quadrupedal Locomotion ◽  
Hindlimb Muscles ◽  
Level Walking ◽  
Ankle Joints ◽  
Hindlimb Kinematics

Carlson-Kuhta, Patricia, Tamara V. Trank, and Judith L. Smith. Forms of forward quadrupedal locomotion. II. A comparison of posture, hindlimb kinematics, and motor patterns for upslope and level walking. J. Neurophysiol. 79: 1687–1701, 1998. To gain insight into the neural mechanisms controlling different forms of quadrupedal walking of normal cats, data on postural orientation, hindlimb kinematics, and motor patterns of selected hindlimb muscles were assessed for four grades of upslope walking, from 25 to 100% (45° incline), and compared with similar data for level treadmill walking (0.6 m/s). Kinematic data for the hip, knee, ankle, and metatarsophalangeal joints were obtained from digitizing ciné film that was synchronized with electromyographic (EMG) records from 13 different hindlimb muscles. Cycle periods, the structure of the step cycle, and paw-contact sequences were similar at all grades and typical of lateral-sequence walking. Also, a few half-bound and transverse gallop steps were assessed from trials at the 100% grade; these steps had shorter cycle periods than the walking steps and less of the cycle (68 vs. 56%) was devoted to stance. Each cat assumed a crouched posture at the steeper grades of upslope walking and stride length decreased, whereas the overall position of the stride shifted caudally with respect to the hip joint. At the steeper grades, the range and duration of swing-related flexion increased at all joints, the stance-phase yield was absent at the knee and ankle joints, and the range of stance-phase extension at knee and ankle joints increased. Patterns of muscle activity for upslope and level walking were similar with some notable exceptions. At the steeper grades, the EMG activity of muscles with swing-related activity, such as the digit flexor muscle, the flexor digitorum longus (FDL), and the knee flexor muscle, the semitendinosus (ST), was prolonged and continued well into midswing. The EMG activity of stance-related muscles also increased in amplitude with grade, and three muscles not active during the stance phase of level walking had stance activity that increased in amplitude and duration at the steepest grades; these muscles were the ST, FDL, and extensor digitorum brevis. Overall the changes in posture, hindlimb kinematics, and the activity patterns of hindlimb muscles during upslope walking reflected the need to continually move the body mass forward and upward during stance and to ensure that the paw cleared the inclined slope during swing. The implications of these changes for the neural control of walking and expected changes in hindlimb kinetics for slope walking are discussed.

scholarly journals Muscular Force Patterns during Level Walking in ACL-Deficient Patients with a Concomitant Medial Meniscus Tear

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Hongshi Huang ◽  
Wei Yin ◽  
Shuang Ren ◽  
Yuanyuan Yu ◽  
Si Zhang ◽  
...  
Keyword(s):  
Stance Phase ◽  
Medial Meniscus ◽  
Rectus Femoris ◽  
Cartilage Degeneration ◽  
Meniscus Tear ◽  
Muscular Force ◽  
Acl Deficiency ◽  
Level Walking ◽  
Significant Difference ◽  
Acl Deficient

Background. The abnormal knee joint motion patterns caused by anterior cruciate ligament (ACL) deficiency are thought to be associated with articular cartilage degeneration. High rates of meniscus tear combined with ACL rupture are observed, and these knees suffer a higher risk of early cartilage degeneration. Research Question. This study investigated lower limb muscular force patterns of ACL-deficient knees with a concomitant medial meniscus tear. Methods. 12 volunteers and 22 patients were recruited, including 12 patients with isolated ACL deficiency (ACLD) and 10 ACL-deficient patients with a concomitant medial meniscus tear (ACLDM). Level walking data at a self-selected speed were collected before surgery. Then, a musculoskeletal dynamic analysis system, AnyBody, was applied to simulate tibiofemoral flexion moments and muscle forces. Results. Our results indicate that the tibiofemoral peak flexion and extension moments in ACLDM patients are significantly lower than in controls. The rectus femoris force in ACLDM patients was significantly lower than in isolated ACL-deficient patients and the controls during mid and terminal stance phase, while no significant difference was found in hamstring and vastus force. Additionally, the gastrocnemius force in ACL-deficient patients both with and without a medial meniscus tear was lower than in controls during mid-stance phase. Significance. The ACLDM patients had lower peak tibiofemoral flexion moment, lower gastrocnemius force in mid-stance phase, and lower rectus femoris force during the mid and terminal stance phase. These results may help clinicians to better understand the muscle function and gait pattern in ACL-deficient patients with a concomitant medial meniscus tear.

scholarly journals Motoneuronal and muscle synergies involved in cat hindlimb control during fictive and real locomotion: a comparison study

2012 ◽  
Vol 107 (8) ◽  
pp. 2057-2071 ◽  
Author(s):  
Sergey N. Markin ◽  
Michel A. Lemay ◽  
Boris I. Prilutsky ◽  
Ilya A. Rybak
Keyword(s):  
Clustering Algorithm ◽  
Minimum Spanning Tree ◽  
Activity Patterns ◽  
Rectus Femoris ◽  
Afferent Feedback ◽  
Research Centre ◽  
Muscle Synergies ◽  
Fictive Locomotion ◽  
Decerebrate Cat ◽  
Level Walking

We compared the activity profiles and synergies of spinal motoneurons recorded during fictive locomotion evoked in immobilized decerebrate cat preparations by midbrain stimulation to the activity profiles and synergies of the corresponding hindlimb muscles obtained during forward level walking in cats. The fictive locomotion data were collected in the Spinal Cord Research Centre, University of Manitoba, and provided by Dr. David McCrea; the real locomotion data were obtained in the laboratories of M. A. Lemay and B. I. Prilutsky. Scatterplot representation and minimum spanning tree clustering algorithm were used to identify the possible motoneuronal and muscle synergies operating during both fictive and real locomotion. We found a close similarity between the activity profiles and synergies of motoneurons innervating one-joint muscles during fictive locomotion and the profiles and synergies of the corresponding muscles during real locomotion. However, the activity patterns of proximal nerves controlling two-joint muscles, such as posterior biceps and semitendinosus (PBSt) and rectus femoris (RF), were not uniform in fictive locomotion preparations and differed from the activity profiles of the corresponding two-joint muscles recorded during forward level walking. Moreover, the activity profiles of these nerves and the corresponding muscles were unique and could not be included in the synergies identified in fictive and real locomotion. We suggest that afferent feedback is involved in the regulation of locomotion via motoneuronal synergies controlled by the spinal central pattern generator (CPG) but may also directly affect the activity of motoneuronal pools serving two-joint muscles (e.g., PBSt and RF). These findings provide important insights into the organization of the spinal CPG in mammals, the motoneuronal and muscle synergies engaged during locomotion, and their afferent control.

Shared muscle synergies in human walking and cycling

2014 ◽  
Vol 112 (8) ◽  
pp. 1984-1998 ◽  
Author(s):  
Filipe O. Barroso ◽  
Diego Torricelli ◽  
Juan C. Moreno ◽  
Julian Taylor ◽  
Julio Gomez-Soriano ◽  
...  
Keyword(s):  
Nonnegative Matrix ◽  
Muscular Activity ◽  
Muscle Synergy ◽  
Emg Activity ◽  
Modular Organization ◽  
Muscle Synergies ◽  
Supporting Evidence ◽  
Healthy Humans ◽  
Common Control ◽  
Secondary Objective

The motor system may rely on a modular organization (muscle synergies activated in time) to execute different tasks. We investigated the common control features of walking and cycling in healthy humans from the perspective of muscle synergies. Three hypotheses were tested: 1) muscle synergies extracted from walking trials are similar to those extracted during cycling; 2) muscle synergies extracted from one of these motor tasks can be used to mathematically reconstruct the electromyographic (EMG) patterns of the other task; 3) muscle synergies of cycling can result from merging synergies of walking. A secondary objective was to identify the speed (and cadence) at which higher similarities emerged. EMG activity from eight muscles of the dominant leg was recorded in eight healthy subjects during walking and cycling at four matched cadences. A factorization technique [nonnegative matrix factorization (NNMF)] was applied to extract individual muscle synergy vectors and the respective activation coefficients behind the global muscular activity of each condition. Results corroborated hypotheses 2 and 3, showing that 1) four synergies from walking and cycling can successfully explain most of the EMG variability of cycling and walking, respectively, and 2) two of four synergies from walking appear to merge together to reconstruct one individual synergy of cycling, with best reconstruction values found for higher speeds. Direct comparison of the muscle synergy vectors of walking and the muscle synergy vectors of cycling ( hypothesis 1) produced moderated values of similarity. This study provides supporting evidence for the hypothesis that cycling and walking share common neuromuscular mechanisms.

scholarly journals Electromyographic Analysis of Traditional and Nontraditional Abdominal Exercises: Implications for Rehabilitation and Training

2006 ◽  
Vol 86 (5) ◽  
pp. 656-671 ◽  
Author(s):  
Rafael F Escamilla ◽  
Eric Babb ◽  
Ryan DeWitt ◽  
Patrick Jew ◽  
Peter Kelleher ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Latissimus Dorsi ◽  
Rectus Femoris ◽  
Rectus Abdominis ◽  
Oblique Muscle ◽  
Emg Activity ◽  
Internal Oblique ◽  
Rectus Femoris Muscle ◽  
Femoris Muscle ◽  
Roll Out

Abstract Background and Purpose. Performing nontraditional abdominal exercises with devices such as abdominal straps, the Power Wheel, and the Ab Revolutionizer has been suggested as a way to activate abdominal and extraneous (nonabdominal) musculature as effectively as more traditional abdominal exercises, such as the crunch and bent-knee sit-up. The purpose of this study was to test the effectiveness of traditional and nontraditional abdominal exercises in activating abdominal and extraneous musculature. Subjects. Twenty-one men and women who were healthy and between 23 and 43 years of age were recruited for this study. Methods. Surface electromyography (EMG) was used to assess muscle activity from the upper and lower rectus abdominis, external and internal oblique, rectus femoris, latissimus dorsi, and lumbar paraspinal muscles while each exercise was performed. The EMG data were normalized to maximum voluntary muscle contractions. Differences in muscle activity were assessed by a 1-way, repeated-measures analysis of variance. Results. Upper and lower rectus abdominis, internal oblique, and latissimus dorsi muscle EMG activity were highest for the Power Wheel (pike, knee-up, and roll-out), hanging knee-up with straps, and reverse crunch inclined 30 degrees. External oblique muscle EMG activity was highest for the Power Wheel (pike, knee-up, and roll-out) and hanging knee-up with straps. Rectus femoris muscle EMG activity was highest for the Power Wheel (pike and knee-up), reverse crunch inclined 30 degrees, and bent-knee sit-up. Lumbar paraspinal muscle EMG activity was low and similar among exercises. Discussion and Conclusion. The Power Wheel (pike, knee-up, and roll-out), hanging knee-up with straps, and reverse crunch inclined 30 degrees not only were the most effective exercises in activating abdominal musculature but also were the most effective in activating extraneous musculature. The relatively high rectus femoris muscle activity obtained with the Power Wheel (pike and knee-up), reverse crunch inclined 30 degrees, and bent-knee sit-up may be problematic for some people with low back problems.

scholarly journals Major role for sensory feedback in soleus EMG activity in the stance phase of walking in man

2000 ◽  
Vol 523 (3) ◽  
pp. 817-827 ◽  
Author(s):  
T. Sinkjær ◽  
J. B. Andersen ◽  
M. Ladouceur ◽  
L. O. D. Christensen ◽  
J. B. Nielsen
Keyword(s):  
Sensory Feedback ◽  
Stance Phase ◽  
Emg Activity

scholarly journals Motor Patterns During Walking on a Slippery Walkway

2010 ◽  
Vol 103 (2) ◽  
pp. 746-760 ◽  
Author(s):  
Germana Cappellini ◽  
Yuri P. Ivanenko ◽  
Nadia Dominici ◽  
Richard E. Poppele ◽  
Francesco Lacquaniti
Keyword(s):  
Motor Output ◽  
Emg Activity ◽  
Head Orientation ◽  
Cycle Duration ◽  
Horizontal Shear ◽  
Motor Patterns ◽  
Spatiotemporal Organization ◽  
Surface Conditions ◽  
Gait Kinematics ◽  
Slippery Surface

Friction and gravity represent two basic physical constraints of terrestrial locomotion that affect both motor patterns and the biomechanics of bipedal gait. To provide insights into the spatiotemporal organization of the motor output in connection with ground contact forces, we studied adaptation of human gait to steady low-friction conditions. Subjects walked along a slippery walkway (7 m long; friction coefficient ≃ 0.06) or a normal, nonslippery floor at a natural speed. We recorded gait kinematics, ground reaction forces, and bilateral electromyographic (EMG) activity of 16 leg and trunk muscles and we mapped the recorded EMG patterns onto the spinal cord in approximate rostrocaudal locations of the motoneuron (MN) pools to characterize the spatiotemporal organization of the motor output. The results revealed several idiosyncratic features of walking on the slippery surface. The step length, cycle duration, and horizontal shear forces were significantly smaller, the head orientation tended to be stabilized in space, whereas arm movements, trunk rotations, and lateral trunk inclinations considerably increased and foot motion and gait kinematics resembled those of a nonplantigrade gait. Furthermore, walking on the slippery surface required stabilization of the hip and of the center-of-body mass in the frontal plane, which significantly improved with practice. Motor patterns were characterized by an enhanced (roughly twofold) level of MN activity, substantial decoupling of anatomical synergists, and the absence of systematic displacements of the center of MN activity in the lumbosacral enlargement. Overall, the results show that when subjects are confronted with unsteady surface conditions, like the slippery floor, they adopt a gait mode that tends to keep the COM centered over the supporting limbs and to increase limb stiffness. We suggest that this behavior may represent a distinct gait mode that is particularly suited to uncertain surface conditions in general.

Forms of Forward Quadrupedal Locomotion. III. A Comparison of Posture, Hindlimb Kinematics, and Motor Patterns for Downslope and Level Walking

1998 ◽  
Vol 79 (4) ◽  
pp. 1702-1716 ◽  
Author(s):  
Judith L. Smith ◽  
Patricia Carlson-Kuhta ◽  
Tamara V. Trank
Keyword(s):  
Ankle Joint ◽  
Neural Control ◽  
Activity Patterns ◽  
Motor Patterns ◽  
Quadrupedal Locomotion ◽  
Hindlimb Muscles ◽  
Level Walking ◽  
Angular Displacements ◽  
External Forces ◽  
Hindlimb Kinematics

Smith, Judith L., Patricia Carlson-Kuhta, and Tamara V. Trank. Forms of forward quadrupedal locomotion. III. A comparison of posture, hindlimb kinematics, and motor patterns for downslope and level walking. J. Neurophysiol. 79: 1702–1716, 1998. To gain further insight into the neural mechanisms for different forms of quadrupedal walking, data on postural orientation, hindlimb kinematics, and motor patterns were assessed for four grades of downslope walking, from 25% (14° slope) to 100% (45°), and compared with data from level and downslope walking at five grades (5–25%) on the treadmill (0.6 m/s). Kinematic data were obtained by digitizing ciné film, and electromyograms (EMGs) synchronized with kinematic records were taken from 13 different hindlimb muscles. At grades from 25 to 75%, cycle periods were similar, but at the steepest grade the cycle was shorter because of a reduced stance phase. Paw-contact sequences at all grades were consistent with lateral-sequence walking, but pace walking often occurred at the steepest grades. The cats crouched at the steeper grades, and crouching was associated with changes in fore- and hindlimb orientation that were consistent with increasing braking forces and decreasing propulsive forces during stance. The average ranges of motion at the hindlimb joints, except at the hip, were often different at the two steepest slopes. During swing, the range of knee- and ankle-joint flexion decreased, and the range and duration of extension increased at the ankle joint to lower the paw downward for contact. During stance the range of flexion during yield increased at the ankle joint, and the range of extension decreased at the knee and metatarsophalangeal joints. Downslope walking was also associated with EMG changes for several muscles. The hip extensors were not active during stance; instead, hip flexors were active, presumably to slow the rate of hip extension. Although ankle extensors were active during stance, their burst durations were truncated and centered around paw contact. Ankle flexors were active after midstance at the steeper slopes before the need to initiate swing, whereas flexor and extensor digit muscles were coactive throughout stance. Overall the changes in posture, hindlimb kinematics, and activity patterns of hindlimb muscles during stance reflected a need to counteract external forces that would accelerate angular displacements at some joints. Implications of these changes are discussed by using current models for the neural control of walking.

Strategies that simplify the control of quadrupedal stance. II. Electromyographic activity

1988 ◽  
Vol 60 (1) ◽  
pp. 218-231 ◽  
Author(s):  
J. M. Macpherson
Keyword(s):  
Muscle Synergy ◽  
Muscle Synergies ◽  
Electromyographic Activity ◽  
Supporting Surface ◽  
Force Vector ◽  
Tuning Curves ◽  
Hindlimb Muscles ◽  
Vector Generation ◽  
High Level ◽  
Selection Of

1. This study tested the hypothesis that muscle synergies underlie the invariance in the direction of corrective forces observed following stance perturbations in the horizontal plane. Electromyographic activity was recorded from selected forelimb and hindlimb muscles of cats subjected to horizontal translations of the supporting surface in 16 different directions. The responses of muscles were quantified for each perturbation, and tuning curves were constructed that related the amplitude of muscle response to the direction of platform movement. 2. Muscle tuning curves tended to group into one of two regions, corresponding to the two directions of force vectors. A few muscles showed clearly different recruitment patterns. The same direction of correction force vector was produced by different patterns of muscle activity, and the particular EMG pattern depended on the direction of platform movement. Therefore a simple muscle synergy organization could not account for the invariance in force vector generation. 3. It is concluded that there is a hierarchy of control in the maintenance of stance in which the vector of force exerted against the ground is a high level, task-dependent controlled variable and the selection of muscles to activate in order to produce the vector is controlled at a lower level. It is proposed that muscles are controlled using a modified synergy strategy. In this scheme, a synergy is not simply a fixed group of muscles, constrained to act as a unit. Rather, muscles are organized as a task-dependent synergy that is tuned or modified as needed by the addition or subtraction of other muscles.

Tonic and Phasic Discharge Patterns in Toe Flexor γ-Motoneurons During Locomotion in the Decerebrate Cat

2002 ◽  
Vol 87 (1) ◽  
pp. 286-294 ◽  
Author(s):  
P. R. Murphy
Keyword(s):  
Mechanical Action ◽  
Emg Activity ◽  
Flexor Hallucis Longus ◽  
Plantar Flexor ◽  
Step Cycle ◽  
Decerebrate Cat ◽  
Hindlimb Muscles ◽  
Discharge Patterns ◽  
Flexor Digitorum ◽  
Α Activity

To investigate the specificity of fusimotor (γ) drive during locomotion, γ-efferents were recorded from the flexor digitorum longus (FDL) and flexor hallucis longus (FHL) nerves in a decerebrate cat preparation. These nerves innervate hindlimb muscles that differ in some aspects of their mechanical action. For both FHL and FDL two stereotyped patterns of γ activity were distinguished. Tonic units fired throughout the step cycle and had less modulation, but higher minimum rates, than phasic units, which were mainly recruited with ankle extensor [soleus (SOL)] electromyogram (EMG) activity. Differences in the relative timing of these patterns were apparent. In FHL the activity of phasic and most tonic neurons peaked after EMG onset. With FDL, tonic units generally reached maximum rate before, while phasic units peaked after, the beginning of EMG activity. During locomotion FHL and FDL α activity were rhythmically recruited with SOL. However, consistent with previous reports, FHL and FDL differed in their patterns of α activity. FHL was stereotyped while FDL was variable. Both FHL and FDL had activity related to ankle extensor EMG, but only FDL exhibited a peak around the end of this phase. No corresponding γ activity was observed in FDL. In conclusion, 1) FHL and FDL received tonic and phasic fusimotor drive; 2) there was no α/γ linkage for the late FDL α burst; 3) phasic γ-efferents in both muscles received similar inputs, linked to plantar flexor α activity; and 4) tonic γ-efferents differed, to the extent that they were modulated at all. The FHL units peaked with the plantar flexor alphas. The FDL neurons generally peaked before α activity even began.

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