scholarly journals When Antagonist Muscles at the Ankle Interfere with Maximal Voluntary Contraction under Isometric and Anisometric Conditions

2021 ◽  
Author(s):  
Maxime Billot ◽  
Julien Duclay ◽  
Philippe Rigoard ◽  
Romain David ◽  
Alain Martin
Keyword(s):  
Muscle Contraction ◽  
Maximal Voluntary Contraction ◽  
Voluntary Contraction ◽  
Triceps Surae ◽  
Emg Activity ◽  
Muscular Performance ◽  
Rehabilitation Programs ◽  
Antagonist Muscles ◽  
Contraction Type ◽  
The Difference

Purpose: While resultant maximal voluntary contraction (MVC) is commonly used to assess muscular performance, the simultaneous activation of antagonist muscles could dramatically underestimate the strength of the agonist muscles. While quantification of antagonist torque has been performed in plantar- (PF) and dorsi-flexion (DF) joint in isometric conditions, it has yet to be determined in anisometric (concentric and eccentric) conditions. Methods: The experiment was performed in 9 participants through 2 sessions (reliability). The MVCs in DF and PF were measured in isometric, concentric and eccentric conditions (10°.s-1). Electromyographic (EMG) activities from the soleus, gastrocnemius medialis and lateralis, and tibialis anterior muscles were simultaneously recorded. The EMG biofeedback method was used to quantify antagonist torque, where participants were asked to maintain a level of EMG activity, corresponding to antagonist EMG activity and related to the muscle contraction type, according to a visual EMG bio-feedback displayed on a screen. Results: Resultant torque significantly underestimated agonist torque in DF MVC (30-65%) and to a lesser extent in PF MVC (3%). Triceps surae antagonist torque was significantly modified with muscle contraction type, showing higher antagonist torque in isometric (29 Nm) than eccentric (23 Nm, p < 0.001) and concentric (14 Nm, p < 0.001) conditions and resulting in modification of the DF MVC torque-velocity shape. The difference between DF eccentric and concentric MVC was attenuated when considered agonist torque (12%) rather than resultant torque (45%). Conclusion: Estimation of the antagonist torque in isometric or anisometric condition brings new insights to assessment of muscular performance and could result in costly misinterpretation in strength training and/or rehabilitation programs.

Limiting mechanisms of force production after repetitive dynamic contractions in human triceps surae

2004 ◽  
Vol 96 (4) ◽  
pp. 1516-1521 ◽  
Author(s):  
M. Klass ◽  
N. Guissard ◽  
J. Duchateau
Keyword(s):  
Maximal Voluntary Contraction ◽  
Muscle Activation ◽  
Voluntary Contraction ◽  
Triceps Surae ◽  
Medial Gastrocnemius ◽  
Emg Activity ◽  
Neutral Position ◽  
M Wave ◽  
Human Triceps Surae ◽  
Fatiguing Contractions

The influence of repetitive dynamic fatiguing contractions on the neuromuscular characteristics of the human triceps surae was investigated in 10 subjects. The load was 50% of the torque produced during a maximal voluntary contraction, and the exercise ended when the ankle range of motion declined to 50% of control. The maximal torque of the triceps surae and the electromyographic (EMG) activities of the soleus and medial gastrocnemius were studied in response to voluntary and electrically induced contractions before and after the fatiguing task and after 5 min of recovery. Reflex activities were also tested by recording the Hoffmann reflex (H reflex) and tendon reflex (T reflex) in the soleus muscle. The results indicated that whereas the maximal voluntary contraction torque, tested in isometric conditions, was reduced to a greater extent ( P < 0.05) at 20° of plantar flexion (-33%) compared with the neutral position (-23%) of the ankle joint, the EMG activity of both muscles was not significantly reduced after fatigue. Muscle activation, tested by the interpolated-twitch method or the ratio of the voluntary EMG to the amplitude of the muscle action potential (M-wave), as well as the neuromuscular transmission and sarcolemmal excitation, tested by the M-wave amplitude, did not change significantly after the fatiguing exercise. Although the H and T reflexes declined slightly (10-13%; P < 0.05) after fatigue, these adjustments did not appear to have a direct deleterious effect on muscle activation. In contrast, alterations in the mechanical twitch time course and postactivation potentiation indicated that intracellular Ca2+-controlled excitation-contraction coupling processes most likely played a major role in the force decrease after dynamic fatiguing contractions performed for short duration.

Contraction level-related modulation of corticomuscular coherence differs between the tibialis anterior and soleus muscles in humans

2012 ◽  
Vol 112 (8) ◽  
pp. 1258-1267 ◽  
Author(s):  
Junichi Ushiyama ◽  
Yoshihisa Masakado ◽  
Toshiyuki Fujiwara ◽  
Tetsuya Tsuji ◽  
Kimitaka Hase ◽  
...  
Keyword(s):  
Frequency Band ◽  
Sensorimotor Cortex ◽  
Maximal Voluntary Contraction ◽  
Tibialis Anterior ◽  
Voluntary Contraction ◽  
Moderate Intensity ◽  
Emg Activity ◽  
Scalp Eeg ◽  
Maximal Peak ◽  
Frequency Changes

The sensorimotor cortex activity measured by scalp EEG shows coherence with electromyogram (EMG) activity within the 15- to 35-Hz frequency band (β-band) during weak to moderate intensity of isometric voluntary contraction. This coupling is known to change its frequency band to the 35- to 60-Hz band (γ-band) during strong contraction. This study aimed to examine whether such contraction level-related modulation of corticomuscular coupling differs between muscles with different muscle compositions and functions. In 11 healthy young adults, we quantified the coherence between EEG over the sensorimotor cortex and rectified EMG during tonic isometric voluntary contraction at 10–70% of maximal voluntary contraction of the tibialis anterior (TA) and soleus (SOL) muscles, respectively. In the TA, the EEG-EMG coherence shifted from the β-band to the γ-band with increasing contraction level. Indeed, the magnitude of β-band EEG-EMG coherence was significantly decreased, whereas that of γ-band coherence was significantly increased, when the contraction level was above 60% of maximal voluntary contraction. In contrast to the TA, the SOL showed no such frequency changes of EEG-EMG coherence with alterations in the contraction levels. In other words, the maximal peak of EEG-EMG coherence in the SOL existed within the β-band, irrespective of the contraction levels. These findings suggest that the central nervous system regulates the frequency of corticomuscular coupling to exert the desired levels of muscle force and, notably, that the applicable rhythmicity of the coupling for performing strong contractions differs between muscles, depending on the physiological muscle compositions and functions of the contracting muscle.

Influence of joint position on ankle plantarflexion in humans

1982 ◽  
Vol 52 (6) ◽  
pp. 1636-1642 ◽  
Author(s):  
D. Sale ◽  
J. Quinlan ◽  
E. Marsh ◽  
A. J. McComas ◽  
A. Y. Belanger
Keyword(s):  
Relaxation Times ◽  
Voluntary Contraction ◽  
Triceps Surae ◽  
Emg Activity ◽  
Optimum Length ◽  
M Wave ◽  
Optimum Position ◽  
Human Muscles ◽  
Slow Twitch ◽  
Torque Development

The contractile properties of the triceps surae (medial and lateral gastrocnemii and soleus) have been studied in humans. In comparison with most other human muscles, the triceps complex had a slow twitch (mean contraction and half-relaxation times 112.4 +/- 11.1 and 99.6 +/- 14.4 ms, respectively) and a low tetanus fusion frequency (60 Hz). Stretching the muscle caused both the contraction and half-relaxation times to become longer. With the knee bent, the optimum length for torque development corresponded to almost full dorsiflexion of the ankle. Similar results were obtained with the knee extended. The optimum position of the ankle differed considerably from the position of the joint when the leg was at rest. Although the position of the ankle joint affected electromyographic (EMG) activity recorded during maximal voluntary contraction, there was little change in the EMG-to-M wave ratio.

Possible mechanisms of muscle cramp from temporal and spatial surface EMG characteristics

2000 ◽  
Vol 88 (5) ◽  
pp. 1698-1706 ◽  
Author(s):  
K. Roeleveld ◽  
B. G. M. van Engelen ◽  
D. F. Stegeman
Keyword(s):  
Maximal Voluntary Contraction ◽  
Muscle Fibers ◽  
Motor Units ◽  
Spatial Arrangement ◽  
Surface Emg ◽  
Voluntary Contraction ◽  
Triceps Surae ◽  
Muscle Cramp ◽  
Channel Surface ◽  
Temporal And Spatial

In this study, the initiation and development of muscle cramp are investigated. For this, we used a 64-channel surface electromyogram (EMG) to study the triceps surae muscle during both cramp and maximal voluntary contraction (MVC) in four cramp-prone subjects and during cramp only in another four cramp-prone subjects. The results show that cramp presents itself as a contraction of a slowly moving fraction of muscle fibers, indicating that either the spatial arrangement of the motoneurons and muscle fibers is highly related or that cramp spreads at a level close to the muscle. Spectral analyses of the EMG and peak-triggered average potentials show the presence of extremely short potentials during cramp compared with during MVC. These results can also be interpreted in two ways. Either the motoneurons fire with enlarged synchronization during MVC compared with cramp, or smaller units than motor units are active, indicating that cramp is initiated close to or even at the muscle fiber level. Further research is needed to draw final conclusions.

Altered reflex sensitivity after repeated and prolonged passive muscle stretching

1999 ◽  
Vol 86 (4) ◽  
pp. 1283-1291 ◽  
Author(s):  
Janne Avela ◽  
Heikki Kyröläinen ◽  
Paavo V. Komi
Keyword(s):  
Maximal Voluntary Contraction ◽  
Large Diameter ◽  
Compound Action Potential ◽  
Muscle Spindles ◽  
Voluntary Contraction ◽  
Creatine Kinase Activity ◽  
Triceps Surae ◽  
Electromyographic Activity ◽  
Zero Crossing ◽  
Maximal Mass

Experiments were carried out to test the effect of prolonged and repeated passive stretching (RPS) of the triceps surae muscle on reflex sensitivity. The results demonstrated a clear deterioration of muscle function immediately after RPS. Maximal voluntary contraction, average electromyographic activity of the gastrocnemius and soleus muscles, and zero crossing rate of the soleus muscle (recorded from 50% maximal voluntary contraction) decreased on average by 23.2, 19.9, 16.5, and 12.2%, respectively. These changes were associated with a clear immediate reduction in the reflex sensitivity; stretch reflex peak-to-peak amplitude decreased by 84.8%, and the ratio of the electrically induced maximal Hoffmann reflex to the maximal mass compound action potential decreased by 43.8%. Interestingly, a significant ( P < 0.01) reduction in the stretch-resisting force of the measured muscles was observed. Serum creatine kinase activity stayed unaltered. This study presents evidence that the mechanism that decreases the sensitivity of short-latency reflexes can be activated because of RPS. The origin of this system seems to be a reduction in the activity of the large-diameter afferents, resulting from the reduced sensitivity of the muscle spindles to repeated stretch.

Wide-pulse-width, high-frequency neuromuscular stimulation: implications for functional electrical stimulation

2006 ◽  
Vol 101 (1) ◽  
pp. 228-240 ◽  
Author(s):  
Evan R. L. Baldwin ◽  
Piotr M. Klakowicz ◽  
David F. Collins
Keyword(s):  
Electrical Stimulation ◽  
Nerve Stimulation ◽  
Maximal Voluntary Contraction ◽  
Neuromuscular Electrical Stimulation ◽  
Initial Step ◽  
Voluntary Contraction ◽  
Triceps Surae ◽  
Muscle Stimulation ◽  
Plantar Flexors ◽  
Wrist Flexors

Electrical stimulation (1-ms pulses, 100 Hz) produces more torque than expected from motor axon activation (extra contractions). This experiment investigates the most effective method of delivering this stimulation for neuromuscular electrical stimulation. Surface stimulation (1-ms pulses; 20 Hz for 2 s, 100 Hz for 2 s, 20 Hz for 3 s) was delivered to triceps surae and wrist flexors (muscle stimulation) and to median and tibial nerves (nerve stimulation) at two intensities. Contractions were evaluated for amplitude, consistency, and stability. Surface electromyograph was collected to assess how H-reflexes and M-waves contribute. In the triceps surae, muscle stimulation produced the largest absolute contractions (23% maximal voluntary contraction), evoked the largest extra contractions as torque increased by 412% after the 100-Hz stimulation, and was more consistent and stable compared with tibial nerve stimulation. Absolute and extra contraction amplitude, consistency, and stability of evoked wrist flexor torques were similar between stimulation types: torques reached 11% maximal voluntary contraction, and extra contractions increased torque by 161%. Extra contractions were 10 times larger in plantar flexors compared with wrist flexors with muscle stimulation but were similar with nerve stimulation. For triceps surae, H reflexes were 3.4 times larger than M waves during nerve stimulation, yet M waves were 15 times larger than H reflexes during muscle stimulation. M waves in the wrist flexors were larger than H reflexes during nerve (8.5 times) and muscle (18.5 times) stimulation. This is an initial step toward utilizing extra contractions for neuromuscular electrical stimulation and the first to demonstrate their presence in the wrist flexors.

scholarly journals Motor unit firing patterns on increasing force during force and position tasks

2021 ◽  
Author(s):  
Shun Kunugi ◽  
Ales Holobar ◽  
Tsutomu Kodera ◽  
Heishiro Toyoda ◽  
Kohei Watanabe
Keyword(s):  
Firing Rate ◽  
Motor Unit ◽  
Maximal Voluntary Contraction ◽  
Gastrocnemius Muscle ◽  
Voluntary Contraction ◽  
Medial Gastrocnemius ◽  
Firing Patterns ◽  
Motor Unit Firing ◽  
The Difference ◽  
Medial Gastrocnemius Muscle

Different neurophysiological strategies are used to perform angle adjustments during motor tasks such as car driving and force-control tasks using a fixed-rigid pedal. However, the difference in motor unit behavior in response to an increasing exerted force between tasks is unknown. This study aimed to investigate the difference in motor unit responsiveness on increasing force between force and position tasks. Twelve healthy participants performed ramp and hold contractions during ankle plantarflexion at 20 and 30% of the maximal voluntary contraction using a rigid pedal (force task) and a free pedal with an inertial load (position task). High-density surface electromyograms were recorded of the medial gastrocnemius muscle and decomposed into individual motor unit firing patterns. Ninety and 109 motor units could be tracked between different target torques in each task. The mean firing rate increased and firing rate variability decreased on 10% maximal voluntary contraction force gain during both force and position tasks. There were no significant differences in these responses between the two tasks. Our results suggest that the motor unit firing rate is similarly regulated between force and position tasks in the medial gastrocnemius muscle with an increase in the exerted force.

scholarly journals Effects of assistive force on the agonist and antagonist muscles in elbow flexion

2017 ◽  
Vol 6 (2) ◽  
Author(s):  
Nursalbiah Nasir ◽  
Keisuke Hayashi ◽  
Ping Yeap Loh ◽  
Satoshi Muraki
Keyword(s):  
Muscle Contraction ◽  
Perceived Exertion ◽  
Elbow Flexion ◽  
Emg Activity ◽  
Antagonist Muscle ◽  
Isometric Muscle Contraction ◽  
Antagonist Muscles ◽  
Agonist And Antagonist ◽  
Agonist And Antagonist Muscles ◽  
Isometric Muscle

This study investigated the responses of the agonist and antagonist muscles against assistive force during isometric muscle contraction. Participants performed isometric elbow flexion at 90º for 30 seconds under two workload conditions (20% and 40% of the maximal voluntary workload) with three levels of assistive force (0%, 50%, and 100% theoretical effectiveness) for 10 seconds. Electromyography (EMG) of the biceps (agonist muscle) and triceps (antagonist muscle) was measured during the task, and perceived exertion was obtained after the task. Assistive force significantly reduced EMG activity in the agonist muscle and the perceived exertion score only at 40% workload. However, the reduction of EMG activity and perceived exertion score were lower than that for the physical estimated effect. In addition, the EMG activity in the antagonist muscle was not influenced, irrespective of workload conditions and the level of assistive force. These results suggested that although the assistive force during isometric muscle contraction relieves exertion of the agonist muscle that accompanies the decrease in perceived exertion, their assistive effects are influenced by various human physiological and anatomical factors. 

scholarly journals The Effect of Static Stretching on Maximal Voluntary Contraction and Force-Time Curve Characteristics

2006 ◽  
Vol 15 (3) ◽  
pp. 185-194 ◽  
Author(s):  
Christos Papadopoulos ◽  
Vasilios I. Kalapotharakos ◽  
Georgios Noussios ◽  
Konstantinos Meliggas ◽  
Evangelia Gantiraga
Keyword(s):  
Maximal Voluntary Contraction ◽  
Isometric Force ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Voluntary Contraction ◽  
Emg Activity ◽  
Static Stretching ◽  
Time Curve ◽  
Significant Difference ◽  
Force Time

Objective:To examine the effect of static stretching on maximal voluntary contraction (MVC) and isometric force-time curve characteristics of leg extensor muscles and EMG activity of rectus femoris (RF), biceps femoris (BF), and gastrocnemius (GA).Design:A within subjects experimental design.Participants:Ten healthy students were tested after a jogging and a jogging/stretch protocol.Intervention:The stretching protocol involved a 10 min jog and seven static stretching exercises.Main Outcomes:Measurements included MVC, time achieved to MVC (TMVC), force at 100ms (F100), index of relative force (IRF), index of rate of force development (IRFD), and average integrated EMG activity (AEMG).Results:There were slight but no significant changes in MVC (1%), TMVC(4.8%), F100(7.8%), IRF (1%), and IRFD(3.5%) between measurement. A significant difference (21%;P< 0.05) in AEMG of RF was found.Conclusions:The present study indicated that a moderate volume of static stretching did not alter significantly the MVC and the isometric force-time curve characteristics. Neural inhibition, as it is reflected from AEMG of RF, did not alter MVC and isometric force-time curve characteristics.

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