scholarly journals Contribution of Cutaneous Inputs From the Hindpaw to the Control of Locomotion. I. Intact Cats

2003 ◽  
Vol 90 (6) ◽  
pp. 3625-3639 ◽  
Author(s):  
L.J.G. Bouyer ◽  
S. Rossignol
Keyword(s):  
Control Level ◽  
Companion Paper ◽  
Treadmill Walking ◽  
Emg Activity ◽  
Ground Reaction Forces ◽  
Phase Duration ◽  
Foot Placement ◽  
Cutaneous Feedback ◽  
Adaptive Mechanisms ◽  
Reaction Forces

The goal of this study was to evaluate the role of hindpaw cutaneous feedback in the control of locomotion, by cutting some (in one cat) or all (in 2 cats) cutaneous nerves bilaterally at ankle level. Kinematic and electromyographic (EMG) recordings were obtained before and for several weeks after denervation during level and incline (15° up and down) treadmill walking. Ladder walking and ground reaction forces were also documented sporadically. Early after the denervation (1–3 days), cats could not walk across a ladder, although deficits were small during level treadmill walking. Increased knee flexion velocity caused a 14% reduction in swing phase duration. EMG activity was consistently increased in knee, ankle, and toe flexors, and in at least one knee or ankle extensor. The adaptive changes during walking on the incline were much reduced after denervation. Ladder walking gradually recovered within 3–7 wk. By this time, level treadmill walking kinematics had completely returned to normal, but EMG activity in flexors remained above control. Incline walking improved but did not return to normal. Mediolateral ground reaction forces during overground walking were increased by 200%. It is concluded that in intact cats, cutaneous inputs contribute more to demanding situations such as walking on a ladder or on inclines than to level walking. Active adaptive mechanisms are likely involved given that the EMG locomotor pattern never returned to control level. The companion paper shows on the other hand that when the same cats are spinalized, these cutaneous inputs become critical for foot placement during locomotion.

Twisting and Bending: The Functional Role of Salamander Lateral Hypaxial Musculature During Locomotion

2001 ◽  
Vol 204 (11) ◽  
pp. 1979-1989 ◽  
Author(s):  
Wallace O. Bennett ◽  
Rachel S. Simons ◽  
Elizabeth L. Brainerd
Keyword(s):  
High Intensity ◽  
High Speed ◽  
The Body ◽  
Transversus Abdominis ◽  
Fine Motor ◽  
Emg Activity ◽  
Ground Reaction Forces ◽  
Terrestrial Locomotion ◽  
Reaction Forces ◽  
Hypaxial Muscle

SUMMARY The function of the lateral hypaxial muscles during locomotion in tetrapods is controversial. Currently, there are two hypotheses of lateral hypaxial muscle function. The first, supported by electromyographic (EMG) data from a lizard (Iguana iguana) and a salamander (Dicamptodon ensatus), suggests that hypaxial muscles function to bend the body during swimming and to resist long-axis torsion during walking. The second, supported by EMG data from lizards during relatively high-speed locomotion, suggests that these muscles function primarily to bend the body during locomotion, not to resist torsional forces. To determine whether the results from D. ensatus hold for another salamander, we recorded lateral hypaxial muscle EMGs synchronized with body and limb kinematics in the tiger salamander Ambystoma tigrinum. In agreement with results from aquatic locomotion in D. ensatus, all four layers of lateral hypaxial musculature were found to show synchronous EMG activity during swimming in A. tigrinum. Our findings for terrestrial locomotion also agree with previous results from D. ensatus and support the torsion resistance hypothesis for terrestrial locomotion. We observed asynchronous EMG bursts of relatively high intensity in the lateral and medial pairs of hypaxial muscles during walking in tiger salamanders (we call these ‘α-bursts’). We infer from this pattern that the more lateral two layers of oblique hypaxial musculature, Mm. obliquus externus superficialis (OES) and obliquus externus profundus (OEP), are active on the side towards which the trunk is bending, while the more medial two layers, Mm. obliquus internus (OI) and transversus abdominis (TA), are active on the opposite side. This result is consistent with the hypothesis proposed for D. ensatus that the OES and OEP generate torsional moments to counteract ground reaction forces generated by forelimb support, while the OI and TA generate torsional moments to counteract ground reaction forces from hindlimb support. However, unlike the EMG pattern reported for D. ensatus, a second, lower-intensity burst of EMG activity (‘β-burst’) was sometimes recorded from the lateral hypaxial muscles in A. tigrinum. As seen in other muscle systems, these β-bursts of hypaxial muscle coactivation may function to provide fine motor control during locomotion. The presence of asynchronous, relatively high-intensity α-bursts indicates that the lateral hypaxial muscles generate torsional moments during terrestrial locomotion, but it is possible that the balance of forces from both α- and β-bursts may allow the lateral hypaxial muscles to contribute to lateral bending of the body as well.

Interactions Between Posture and Locomotion: Motor Patterns in Humans Walking With Bent Posture Versus Erect Posture

2000 ◽  
Vol 83 (1) ◽  
pp. 288-300 ◽  
Author(s):  
R. Grasso ◽  
M. Zago ◽  
F. Lacquaniti
Keyword(s):  
Gait Cycle ◽  
Emg Activity ◽  
Muscle Synergies ◽  
Ground Reaction Forces ◽  
Motor Patterns ◽  
Erect Posture ◽  
Body Segments ◽  
Plane Orientation ◽  
Temporal Coupling ◽  
Reaction Forces

Human erect locomotion is unique among living primates. Evolution selected specific biomechanical features that make human locomotion mechanically efficient. These features are matched by the motor patterns generated in the CNS. What happens when humans walk with bent postures? Are normal motor patterns of erect locomotion maintained or completely reorganized? Five healthy volunteers walked straight and forward at different speeds in three different postures (regular, knee-flexed, and knee- and trunk-flexed) while their motion, ground reaction forces, and electromyographic (EMG) activity were recorded. The three postures imply large differences in the position of the center of body mass relative to the body segments. The elevation angles of the trunk, pelvis, and lower limb segments relative to the vertical in the sagittal plane, the ground reaction forces and the rectified EMGs were analyzed over the gait cycle. The waveforms of the elevation angles along the gait cycle remained essentially unchanged irrespective of the adopted postures. The first two harmonics of these kinematic waveforms explain >95% of their variance. The phase shift but not the amplitude ratio between the first harmonic of the elevation angle waveforms of adjacent pairs was affected systematically by changes in posture. Thigh, shank, and foot angles covaried close to a plane in all conditions, but the plane orientation was systematically different in bent versus erect locomotion. This was explained by the changes in the temporal coupling among the three segments. For walking speeds >1 m s−1, the plane orientation of bent locomotion indicates a much lower mechanical efficiency relative to erect locomotion. Ground reaction forces differed prominently in bent versus erect posture displaying characteristics intermediate between those typical of walking and those of running. Mean EMG activity was greater in bent postures for all recorded muscles independent of the functional role. The waveforms of the muscle activities and muscle synergies also were affected by the adopted posture. We conclude that maintaining bent postures does not interfere either with the generation of segmental kinematic waveforms or with the planar constraint of intersegmental covariation. These characteristics are maintained at the expense of adjustments in kinetic parameters, muscle synergies and the temporal coupling among the oscillating body segments. We argue that an integrated control of gait and posture is made possible because these two motor functions share some common principles of spatial organization.

scholarly journals Effects of Cooling on Ankle Muscle Strength, Electromyography, and Gait Ground Reaction Forces

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Amitava Halder ◽  
Chuansi Gao ◽  
Michael Miller
Keyword(s):  
Cold Water ◽  
Isometric Force ◽  
Force Plate ◽  
Muscle Performance ◽  
Emg Activity ◽  
Ground Reaction Forces ◽  
Local Cooling ◽  
Ankle Muscle ◽  
Reaction Forces ◽  
And Performance

The effects of cooling on neuromuscular function and performance during gait are not fully examined. The purpose of this study was to investigate the effects of local cooling for 20 min in cold water at 10°C in a climate chamber also at 10°C on maximal isometric force and electromyographic (EMG) activity of the lower leg muscles. Gait ground reaction forces (GRFs) were also assessed. Sixteen healthy university students participated in the within subject design experimental study. Isometric forces of the tibialis anterior (TA) and the gastrocnemius medialis (GM) were measured using a handheld dynamometer and the EMG was recorded using surface electrodes. Ground reaction forces during gait and the required coefficient of friction (RCOF) were recorded using a force plate. There was a significantly reduced isometric maximum force in the TA muscle (P<0.001) after cooling. The mean EMG amplitude of GM muscle was increased after cooling (P<0.003), indicating that fatigue was induced. We found no significant changes in the gait GRFs and RCOF on dry and level surface. These findings may indicate that local moderate cooling 20 min of 10°C cold water, may influence maximal muscle performance without affecting activities at sub-maximal effort.

scholarly journals Comparison of the Vertical Force Distribution in the Paws of Dogs with Coxarthrosis and Sound Dogs Walking over a Pressure Plate

Animals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 986 ◽  
Author(s):  
Jane P. L. Moreira ◽  
Alexander Tichy ◽  
Barbara Bockstahler
Keyword(s):  
Hind Limb ◽  
Stance Phase ◽  
Force Distribution ◽  
Total Force ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Phase Duration ◽  
Contralateral Limb ◽  
Pressure Plate ◽  
Reaction Forces

In the present study, we used a pressure plate to investigate the ground reaction forces of limbs and the vertical force distribution (VFD) within the paws of dogs with coxarthrosis. We included 23 sound dogs (GSou) and 23 dogs with hip osteoarthrosis (GCox). The dogs walked over a pressure plate and the peak vertical force (PFz), vertical impulse (IFz) as the percentage of the total force, and time of occurrence of PFz as a percent of the stance phase duration (TPFz%) were evaluated, as well for the entire limb as in the paws (where the paws were divided into four quadrants). The GCox presented a lower PFz% in the lame hind limb than in others and transferred the weight to the caudal quadrants of the front limbs. IFz% was lower in the lame limb and was counterbalanced through higher loading of the caudal quadrants in all unaffected limbs. TPFz% was reached later in the lame limb than in the contralateral limb and the GSou, specifically in the caudomedial quadrant. In conclusion, we found complex compensatory effects of lameness in the hind limb, and this methodology was useful to define the VFD within the paws of dogs.

EFFECTIVENESS OF FLOOR MARKINGS FOR CONTROLLING CUT WIDTH DURING SIDE CUTTING TASKS IN LABORATORY EXPERIMENTS

2020 ◽  
Vol 20 (01) ◽  
pp. 1950076
Author(s):  
JING WEN PAN ◽  
THORSTEN STERZING ◽  
JUN WEI PANG ◽  
YAOHUI KELVIN CHUA ◽  
PUI WAH KONG
Keyword(s):  
Lower Extremity ◽  
Hip Joint ◽  
Laboratory Experiments ◽  
Ground Reaction Forces ◽  
Basketball Players ◽  
Foot Placement ◽  
Body Postures ◽  
Motion Data ◽  
Reaction Forces ◽  
The Difference

This study examined the effectiveness of floor markings for controlling cut width during the analysis of side cutting maneuvers. Eleven male basketball players performed two side cutting maneuvers of narrow (30[Formula: see text]cm) and wide (45[Formula: see text]cm) cut widths and were guided by floor markings. Ground reaction forces, together with ankle, knee, and hip joint ranges of motion (ROM), and respective joint moments were determined. Cut widths were verified by two approaches by calculating the actual foot-to-foot and foot-to-pelvis distances from motion data. Biomechanical lower extremity loading showed no significant differences in most kinetic and kinematic variables between narrow and wide cuts. The difference in foot-to-foot distance (15.1 [11.6, 18.7] cm, [Formula: see text] between conditions corresponded well with floor markings, however, the difference in foot-to-pelvis distance was much smaller (2.3 [0.3, 4.4] cm, [Formula: see text]. It is concluded that floor markings are not sufficient for controlling the actual anatomical cut width in laboratory experiments. Participants may adjust their body postures to maintain similar lower extremity loading when performing side cuts differing in foot placement width. Cut width should be represented by foot-to-pelvis distance and not foot-to-foot distance.

scholarly journals Effects of Running on Sand vs. Stable Ground on Kinetics and Muscle Activities in Individuals With Over-Pronated Feet

2022 ◽  
Vol 12 ◽  
Author(s):  
AmirAli Jafarnezhadgero ◽  
Nasrin Amirzadeh ◽  
Amir Fatollahi ◽  
Marefat Siahkouhian ◽  
Anderson S. Oliveira ◽  
...  
Keyword(s):  
Tibialis Anterior ◽  
Force Plate ◽  
Rectus Femoris ◽  
Lower Limbs ◽  
Emg Activity ◽  
Ground Reaction Forces ◽  
Compensatory Mechanism ◽  
Running Speed ◽  
Loading Rates ◽  
Reaction Forces

Background: In terms of physiological and biomechanical characteristics, over-pronation of the feet has been associated with distinct muscle recruitment patterns and ground reaction forces during running.Objective: The aim of this study was to evaluate the effects of running on sand vs. stable ground on ground-reaction-forces (GRFs) and electromyographic (EMG) activity of lower limb muscles in individuals with over-pronated feet (OPF) compared with healthy controls.Methods: Thirty-three OPF individuals and 33 controls ran at preferred speed and in randomized-order over level-ground and sand. A force-plate was embedded in an 18-m runway to collect GRFs. Muscle activities were recorded using an EMG-system. Data were adjusted for surface-related differences in running speed.Results: Running on sand resulted in lower speed compared with stable ground running (p &lt; 0.001; d = 0.83). Results demonstrated that running on sand produced higher tibialis anterior activity (p = 0.024; d = 0.28). Also, findings indicated larger loading rates (p = 0.004; d = 0.72) and greater vastus medialis (p &lt; 0.001; d = 0.89) and rectus femoris (p = 0.001; d = 0.61) activities in OPF individuals. Controls but not OPF showed significantly lower gluteus-medius activity (p = 0.022; d = 0.63) when running on sand.Conclusion: Running on sand resulted in lower running speed and higher tibialis anterior activity during the loading phase. This may indicate alterations in neuromuscular demands in the distal part of the lower limbs when running on sand. In OPF individuals, higher loading rates together with greater quadriceps activity may constitute a proximal compensatory mechanism for distal surface instability.

Motor Patterns for Human Gait: Backward Versus Forward Locomotion

1998 ◽  
Vol 80 (4) ◽  
pp. 1868-1885 ◽  
Author(s):  
R. Grasso ◽  
L. Bianchi ◽  
F. Lacquaniti
Keyword(s):  
Time Course ◽  
Cross Correlation ◽  
Gait Cycle ◽  
Human Gait ◽  
Emg Activity ◽  
Ground Reaction Forces ◽  
Motor Patterns ◽  
Cross Correlation Analysis ◽  
Reaction Forces ◽  
Forward Locomotion

Grasso, R., L. Bianchi, and F. Lacquaniti. Motor patterns for human gait: backward versus forward locomotion. J. Neurophysiol. 80: 1868–1885, 1998. Seven healthy subjects walked forward (FW) and backward (BW) at different freely chosen speeds, while their motion, ground reaction forces, and electromyographic (EMG) activity from lower limb muscles were recorded. We considered the time course of the elevation angles of the thigh, shank, and foot segments in the sagittal plane, the anatomic angles of the hip, knee, and ankle joints, the vertical and longitudinal ground reaction forces, and the rectified EMGs. The elevation angles were the most reproducible variables across trials in each walking direction. After normalizing the time course of each variable over the gait cycle duration, the waveforms of all elevation angles in BW gait were essentially time reversed relative to the corresponding waveforms in FW gait. Moreover, the changes of the thigh, shank, and foot elevation covaried along a plane during the whole gait cycle in both FW and BW directions. Cross-correlation analysis revealed that the phase coupling among these elevation angles is maintained with a simple reversal of the delay on the reversal of walking direction. The extent of FW–BW correspondence also was good for the hip angle, but it was smaller for the knee and ankle angles and for the ground reaction forces. The EMG patterns were drastically different in the two movement directions as was the organization of the muscular synergies measured by cross-correlation analysis. Moreover, at any given speed, the mean EMG activity over the gait cycle was generally higher in BW than in FW gait, suggesting a greater level of energy expenditure in the former task. We argue that conservation of kinematic templates across gait reversal at the expense of a complete reorganization of muscle synergies does not arise from biomechanical constraints but may reflect a behavioral goal achieved by the central networks involved in the control of locomotion.

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