Contribution of Sensory Feedback to the Generation of Extensor Activity During Walking in the Decerebrate Cat

1999 ◽  
Vol 81 (2) ◽  
pp. 758-770 ◽  
Author(s):  
Gordon W. Hiebert ◽  
Keir G. Pearson
Keyword(s):  
Sensory Feedback ◽  
Knee Extensor ◽  
Afferent Feedback ◽  
Knee Extensors ◽  
Total Contribution ◽  
Decerebrate Cat ◽  
Dorsal Roots ◽  
Level Of Activity ◽  
Extensor Muscles ◽  
Decerebrate Cats

Contribution of sensory feedback to the generation of extensor activity during walking in the decerebrate cat. In this investigation we have estimated the afferent contribution to the generation of activity in the knee and ankle extensor muscles during walking in decerebrate cats by loading and unloading extensor muscles, and by unilateral deafferentation of a hind leg. The total contribution of afferent feedback to extensor burst generation was estimated by allowing one hind leg to step into a hole in the treadmill belt on which the animal was walking. In the absence of ground support the level of activity in knee and ankle extensor muscles was reduced to ∼70% of normal. Activity in the ankle extensors could be restored during the “foot-in-hole” trials by selectively resisting extension at the ankle. Thus feedback from proprioceptors in the ankle extensor muscles probably makes a large contribution to burst generation in these muscles during weight-bearing steps. Similarly, feedback from proprioceptors in knee extensor appears to contribute substantially to the activation of knee extensor muscles because unloading and loading these muscles, by lifting and dropping the hindquarters, strongly reduced and increased, respectively, the level of activity in the knee extensors. This conclusion was supported by the finding that partial deafferentation of one hind leg by transection of the L4–L6 dorsal roots reduced the level of activity in the knee extensors by ∼50%, but did not noticeably influence the activity in ankle extensor muscles. However, extending the deafferentation to include the L7–S2dorsal roots decreased the ankle extensor activity. We conclude that afferent feedback contributes to more than one-half of the input to knee and ankle extensor motoneurons during the stance phase of walking in decerebrate cats. The continuous contribution of afferent feedback to the generation of extensor activity could function to automatically adjust the intensity of activity to meet external demands.

Knee angle-dependent oxygen consumption during isometric contractions of the knee extensors determined with near-infrared spectroscopy

2005 ◽  
Vol 99 (2) ◽  
pp. 579-586 ◽  
Author(s):  
C. J. de Ruiter ◽  
M. D. de Boer ◽  
M. Spanjaard ◽  
A. de Haan
Keyword(s):  
Oxygen Consumption ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Rectus Femoris ◽  
Knee Extensors ◽  
Isometric Contractions ◽  
Knee Angle ◽  
Extensor Muscles ◽  
Knee Extensor Muscles

Fatigue resistance of knee extensor muscles is higher during voluntary isometric contractions at short compared with longer muscle lengths. In the present study we hypothesized that this would be due to lower energy consumption at short muscle lengths. Ten healthy male subjects performed isometric contractions with the knee extensor muscles at a 30, 60, and 90° knee angle (full extension = 0°). At each angle, muscle oxygen consumption (mV̇o2) of the rectus femoris, vastus lateralis, and vastus medialis muscle was obtained with near-infrared spectroscopy. mV̇o2 was measured during maximal isometric contractions and during contractions at 10, 30, and 50% of maximal torque capacity. During all contractions, blood flow to the muscle was occluded with a pressure cuff (450 mmHg). mV̇o2 significantly ( P < 0.05) increased with torque and at all torque levels, and for each of the three muscles mV̇o2 was significantly lower at 30° compared with 60° and 90° and mV̇o2 was similar ( P > 0.05) at 60° and 90°. Across all torque levels, average (± SD) mV̇o2 at the 30° angle for vastus medialis, rectus femoris, and vastus lateralis, respectively, was 70.0 ± 10.4, 72.2 ± 12.7, and 75.9 ± 8.0% of the average mV̇o2 obtained for each torque at 60 and 90°. In conclusion, oxygen consumption of the knee extensors was significantly lower during isometric contractions at the 30° than at the 60° and 90° knee angle, which probably contributes to the previously reported longer duration of sustained isometric contractions at relatively short muscle lengths.

scholarly journals Comparison of Recovery Strategies on Maximal Force-Generating Capacity and Electromyographic Activity Level of the Knee Extensor Muscles

2011 ◽  
Vol 46 (4) ◽  
pp. 386-394 ◽  
Author(s):  
Nidhal Zarrouk ◽  
Haithem Rebai ◽  
Abdelmoneem Yahia ◽  
Nizar Souissi ◽  
François Hug ◽  
...  
Keyword(s):  
Knee Extensor ◽  
Neuromuscular Fatigue ◽  
Activity Level ◽  
Knee Extensors ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Active Recovery ◽  
Concentric Exercise ◽  
Extensor Muscles ◽  
Knee Extensor Muscles

Context: With regard to intermittent training exercise, the effects of the mode of recovery on subsequent performance are equivocal. Objective: To compare the effects of 3 types of recovery intervention on peak torque (PT) and electromyographic (EMG) activity of the knee extensor muscles after fatiguing isokinetic intermittent concentric exercise. Design: Crossover study. Setting: Research laboratory. Patients or Other Participants: Eight elite judo players (age = 18.4 ± 1.4 years, height = 180 ± 3 cm, mass = 77.0 ± 4.2 kg). Intervention(s): Participants completed 3 randomized sessions within 7 days. Each session consisted of 5 sets of 10 concentric knee extensions at 80% PT at 120°/s, with 3 minutes of recovery between sets. Recovery interventions were passive, active, and electromyostimulation. The PT and maximal EMG activity were recorded simultaneously while participants performed isokinetic dynamometer trials before and 3 minutes after the resistance exercise. Main Outcome Measure(s): The PT and maximal EMG activity from the knee extensors were quantified at isokinetic velocities of 60°/s, 120°/s, and 180°/s, with 5 repetitions at each velocity. Results: The reduction in PT observed after electromyo-stimulation was less than that seen after passive (P &lt; .001) or active recovery (P &lt; .001). The reduction in PT was less after passive recovery than after active recovery (P &lt; .001). The maximal EMG activity level observed after electromyostimulation was higher than that seen after active recovery (P &lt; .05). Conclusions: Electromyostimulation was an effective recovery tool in decreasing neuromuscular fatigue after high-intensity, intermittent isokinetic concentric exercise for the knee extensor muscles. Also, active recovery induced the greatest amount of neuromuscular fatigue.

scholarly journals Patterns of intermuscular inhibitory force feedback across cat hindlimbs suggest a flexible system for regulating whole limb mechanics

2018 ◽  
Vol 119 (2) ◽  
pp. 668-678 ◽  
Author(s):  
Mark A. Lyle ◽  
T. Richard Nichols
Keyword(s):  
Neural Control ◽  
Force Feedback ◽  
Control Variable ◽  
Knee Extensors ◽  
Flexor Hallucis Longus ◽  
Directional Bias ◽  
Decerebrate Cat ◽  
Golgi Tendon Organs ◽  
Extensor Muscles ◽  
Inhibitory Feedback

Prior work has suggested that Golgi tendon organ feedback, via its distributed network linking muscles spanning all joints, could be used by the nervous system to help regulate whole limb mechanics if appropriately organized. We tested this hypothesis by characterizing the patterns of intermuscular force-dependent feedback between the primary extensor muscles spanning the knee, ankle, and toes in decerebrate cat hindlimbs. Intermuscular force feedback was evaluated by stretching tendons of selected muscles in isolation and in pairwise combinations and then measuring the resulting force-dependent intermuscular interactions. The relative inhibitory feedback between extensor muscles was examined, as well as symmetry of the interactions across limbs. Differences in the directional biases of inhibitory feedback were observed across cats, with three patterns identified as points on a spectrum: pattern 1, directional bias of inhibitory feedback onto the ankle extensors and toe flexors; pattern 2, convergence of inhibitory feedback onto ankle extensors and mostly balanced inhibitory feedback between vastus muscle group and flexor hallucis longus, and pattern 3, directional bias of inhibitory feedback onto ankle and knee extensors. The patterns of inhibitory feedback, while different across cats, were symmetric across limbs of individual cats. The variable but structured distribution of force feedback across cat hindlimbs provides preliminary evidence that inhibitory force feedback could be a regulated neural control variable. We propose the directional biases of inhibitory feedback observed experimentally could provide important task-dependent benefits, such as directionally appropriate joint compliance, joint coupling, and compensation for nonuniform inertia. NEW & NOTEWORTHY Feedback from Golgi tendon organs project widely among extensor motor nuclei in the spinal cord. The distributed nature of force feedback suggests these pathways contribute to the global regulation of limb mechanics. Analysis of this network in individual animals indicates that the strengths of these pathways can be reorganized appropriately for a variety of motor tasks, including level walking, slope walking, and landing.

Strength training counteracts motor performance losses during bed rest

2003 ◽  
Vol 95 (4) ◽  
pp. 1485-1492 ◽  
Author(s):  
Minoru Shinohara ◽  
Yasuhide Yoshitake ◽  
Motoki Kouzaki ◽  
Hideoki Fukuoka ◽  
Tetsuo Fukunaga
Keyword(s):  
Strength Training ◽  
Muscle Activation ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Bed Rest ◽  
Training Group ◽  
Medial Gastrocnemius ◽  
Knee Extensors ◽  
Extensor Muscles ◽  
Muscle Groups

The purpose of the study was to determine the effect of bed rest with or without strength training on torque fluctuations and activation strategy of the muscles. Twelve young men participated in a 20-day bed rest study. Subjects were divided into a non-training group (BRCon) and a strength-training group (BRTr). The training comprised dynamic calf-raise and leg-press exercises. Before and after bed rest, subjects performed maximal contractions and steady submaximal isometric contractions of the ankle extensor muscles and of the knee extensor muscles (2.5-10% of maximal torque). Maximal torque decreased for both the ankle extensors (9%, P < 0.05) and knee extensors (16%, P < 0.05) in BRCon but not in BRTr. For the ankle extensors, the coefficient of variation (CV) for torque increased in both groups ( P < 0.05), with a greater amount ( P < 0.05) in BRCon (88%) compared with BRTr (41%). For the knee extensors, an increase in the CV for torque was observed only in BRCon (22%). The increase in the CV for torque in BRCon accompanied the greater changes in electromyogram amplitude of medial gastrocnemius (122%) and vastus lateralis (59%) compared with BRTr ( P < 0.05). The results indicate that fluctuations in torque during submaximal contractions of the extensor muscles in the leg increase after bed rest and that strength training counteracted the decline in performance. The response varied across muscle groups. Alterations in muscle activation may lead to an increase in fluctuations in motor output after bed rest.

scholarly journals Role of muscle spindle feedback in regulating muscle activity strength during walking at different speed in mice

2018 ◽  
Vol 120 (5) ◽  
pp. 2484-2497 ◽  
Author(s):  
William P. Mayer ◽  
Andrew J. Murray ◽  
Susan Brenner-Morton ◽  
Thomas M. Jessell ◽  
Warren G. Tourtellotte ◽  
...  
Keyword(s):  
Muscle Spindle ◽  
Amplitude Modulation ◽  
Muscle Activity ◽  
Sensory Feedback ◽  
Walking Speed ◽  
Muscle Spindles ◽  
Afferent Feedback ◽  
Triceps Surae ◽  
Extensor Muscles

Terrestrial animals increase their walking speed by increasing the activity of the extensor muscles. However, the mechanism underlying how this speed-dependent amplitude modulation is achieved remains obscure. Previous studies have shown that group Ib afferent feedback from Golgi tendon organs that signal force is one of the major regulators of the strength of muscle activity during walking in cats and humans. In contrast, the contribution of group Ia/II afferent feedback from muscle spindle stretch receptors that signal angular displacement of leg joints is unclear. Some studies indicate that group II afferent feedback may be important for amplitude regulation in humans, but the role of muscle spindle feedback in regulation of muscle activity strength in quadrupedal animals is very poorly understood. To examine the role of feedback from muscle spindles, we combined in vivo electrophysiology and motion analysis with mouse genetics and gene delivery with adeno-associated virus. We provide evidence that proprioceptive sensory feedback from muscle spindles is important for the regulation of the muscle activity strength and speed-dependent amplitude modulation. Furthermore, our data suggest that feedback from the muscle spindles of the ankle extensor muscles, the triceps surae, is the main source for this mechanism. In contrast, muscle spindle feedback from the knee extensor muscles, the quadriceps femoris, has no influence on speed-dependent amplitude modulation. We provide evidence that proprioceptive feedback from ankle extensor muscles is critical for regulating muscle activity strength as gait speed increases. NEW & NOTEWORTHY Animals upregulate the activity of extensor muscles to increase their walking speed, but the mechanism behind this is not known. We show that this speed-dependent amplitude modulation requires proprioceptive sensory feedback from muscle spindles of ankle extensor muscle. In the absence of muscle spindle feedback, animals cannot walk at higher speeds as they can when muscle spindle feedback is present.

The effects of isometric resistance training on stretch reflex induced tremor in the knee extensor muscles

2013 ◽  
Vol 114 (12) ◽  
pp. 1647-1656 ◽  
Author(s):  
Rade Durbaba ◽  
Angela Cassidy ◽  
Francesco Budini ◽  
Andrea Macaluso
Keyword(s):  
Resistance Training ◽  
High Intensity ◽  
Stretch Reflex ◽  
Knee Extensor ◽  
Training Group ◽  
Control Group ◽  
Force Matching ◽  
Level Of Activity ◽  
Extensor Muscles ◽  
Knee Extensor Muscles

This study examines the effect of 4 wk of high-intensity isometric resistance training on induced tremor in knee extensor muscles. Fourteen healthy volunteers were assigned to either the training group ( n = 7) or the nontraining control group ( n = 7). Induced tremor was assessed by measuring force fluctuations during anisometric contractions against spring loading, whose compliance was varied to allow for preferential activation of the short or long latency stretch reflex components. Effects of high-intensity isometric resistance training on induced tremor was assessed under two contraction conditions: relative force matching, where the relative level of activity was equal for both pre- and post-training sessions, set at 30% maximum voluntary contraction (MVC), and absolute force matching, where the level of activity was set to 30% pretrained MVC. The training group experienced a 26.5% increase in MVC in contrast to the 0.8% for the control group. For relative force-matching contractions, induced tremor amplitude and frequency did not change in either the training or control group. During absolute force-matching contractions, induced tremor amplitude was decreased by 37.5% and 31.6% for the short and long components, respectively, with no accompanying change in frequency, for the training group. No change in either measure was observed in the control group for absolute force-matching contractions. The results are consistent with high-intensity isometric resistance training induced neural changes leading to increased strength, coupled with realignment of stretch reflex automatic gain compensation to the new maximal force output. Also, previous reported reductions in anisometric tremor following strength training may partly be due to changed stretch reflex behavior.

scholarly journals Spinal contribution to neuromuscular recovery differs between elbow-flexor and knee-extensor muscles after a maximal sustained fatiguing task

2020 ◽  
Vol 124 (3) ◽  
pp. 763-773 ◽  
Author(s):  
Gianluca Vernillo ◽  
John Temesi ◽  
Matthieu Martin ◽  
Renata L. Krüger ◽  
Guillaume Y. Millet
Keyword(s):  
Knee Extensor ◽  
Elbow Flexor ◽  
Knee Extensors ◽  
Elbow Flexors ◽  
Recovery Pattern ◽  
Motoneuron Excitability ◽  
Neural Processes ◽  
Extensor Muscles ◽  
Voluntary Contractions ◽  
Knee Extensor Muscles

By comparing the changes in motoneuron excitability in elbow-flexor and knee-extensor muscles after sustained fatiguing maximal voluntary contractions, this study shows that motoneuron recovery behavior depends on the muscle performing the exercise. A different recovery pattern in motoneuron excitability occurs in elbow flexors as it recovered by 60 s whereas knee extensors were unaffected by fatigue. This finding can help to increase understanding of the effect of a fatigue and subsequent recovery on neural processes.

Effects of age on human muscle torque, velocity, and power in two muscle groups

2003 ◽  
Vol 95 (6) ◽  
pp. 2361-2369 ◽  
Author(s):  
I. R. Lanza ◽  
T. F. Towse ◽  
G. E. Caldwell ◽  
D. M. Wigmore ◽  
J. A. Kent-Braun
Keyword(s):  
Dynamic Performance ◽  
Knee Extensor ◽  
Knee Extensors ◽  
Target Velocity ◽  
Downward Shift ◽  
Age Related ◽  
Extensor Muscles ◽  
Older Subjects ◽  
Muscle Groups ◽  
Knee Extensor Muscles

The purpose of this study was to test the hypotheses that, under isovelocity conditions, older compared with young humans would 1) be slower to reach target velocity and 2) exhibit a downward shift in the torque-velocity and power-velocity relationships in the ankle dorsiflexor and knee extensor muscles. We studied 12 young (26 ± 5 yr, 6 men/6 women) and 12 older (72 ± 6 yr, 6 men/6 women) healthy adults during maximal voluntary concentric contractions at preset target velocities (dorsiflexion: 0–240°/s; knee extension: 0–400°/s) using an isokinetic dynamometer. The time to target velocity was longer in older subjects in the dorsiflexors and knee extensors (both P ≤ 0.02). Averaged across all velocities, older subjects produced ∼26% less concentric torque and power in the dorsiflexors ( P < 0.01) and ∼32% less in the knee extensors ( P < 0.01). The downward shift in the torque-velocity relationship persisted even when torque was expressed relative to each subject's maximum. In the knee extensors only, the age-related decrement in power increased with increasing velocities, suggesting that this muscle group may be more susceptible to age-related losses of function than the dorsiflexor muscles are. In support of our hypotheses, these results demonstrate an age-related impairment in the dynamic performance of two functionally distinct muscle groups in healthy older adults. With age, the impairment of dynamic performance appears to exceed the loss of isometric performance, particularly in the knee extensor muscles.

Effects of chronic low-frequency electrical stimulation of human knee extensor muscles exposed to static passive stretching

2006 ◽  
Vol 32 (1) ◽  
pp. 74-80 ◽  
Author(s):  
B. S. Shenkman ◽  
E. V. Lyubaeva ◽  
D. V. Popov ◽  
A. I. Netreba ◽  
O. S. Tarasova ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Low Frequency ◽  
Knee Extensor ◽  
Human Knee ◽  
Passive Stretching ◽  
Extensor Muscles ◽  
Knee Extensor Muscles ◽  
Stimulation Of

scholarly journals Quadriceps Femoris and Hamstring Muscle Function in a Person With an Unstable Knee

1999 ◽  
Vol 79 (1) ◽  
pp. 66-75 ◽  
Author(s):  
Murray E Maitland ◽  
Stanley V Ajemian ◽  
Esther Suter
Keyword(s):  
Gait Analysis ◽  
Cruciate Ligament ◽  
Specific Treatment ◽  
Knee Extensor ◽  
Left Knee ◽  
Thigh Muscle ◽  
Knee Extensors ◽  
Term Outcome ◽  
Electromyographic Biofeedback ◽  
Muscle Inhibition

Abstract Background and Purpose. The purpose of this case report is to describe the evaluation, treatment, and short-term outcome for an individual with chronic, progressively worsening instability of the knee during gait associated with anterior cruciate ligament (ACL) insufficiency.Case Description. The patient was a 34-year-old man who sustained bilateral ACL injuries. Subsequently, an autograft reconstruction of the left knee ACL was performed. Eight months post-reconstruction, the left knee was unstable despite bracing. Gait analysis and tests to determine the presence of muscle inhibition were performed prior to and after 12 weeks of training. Isometric torque of the knee extensors and flexors was measured with the knee in 90 degrees of flexion. A training program primarily consisted of electromyographic biofeedback during thigh muscle exercises, balance exercises, and gait.Outcomes. Muscle inhibition decreased and maximal isometric knee flexion and extension torques increased during the 12-week training period. Gait analysis demonstrated a 50% decrease in the maximum knee extensor moment and an increase in walking speed.Discussion. Selected gait variables, torque production, and muscle inhibition may change in a person with an unstable knee. The measurement of variables that have previously been documented as mechanisms of knee instability during walking allows for the selection of a specific treatment approach.

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