Task dependency of motor adaptations to an acute noxious stimulation

2014 ◽  
Vol 111 (11) ◽  
pp. 2298-2306 ◽  
Author(s):  
François Hug ◽  
Paul W. Hodges ◽  
Kylie Tucker
Keyword(s):  
Elastic Modulus ◽  
Degrees Of Freedom ◽  
Isometric Force ◽  
Vastus Lateralis ◽  
Knee Extension ◽  
Noxious Stimulation ◽  
Shear Elastic Modulus ◽  
Emg Amplitude ◽  
Single Leg Squat ◽  
Control Pain

This study explored motor adaptations in response to an acute noxious stimulation during three tasks that differed in the number of available degrees of freedom. Fifteen participants performed three isometric force-matched tasks (single leg knee extension, single leg squat, and bilateral leg squat) in three conditions (Control, Pain, and Washout). Pain was induced by injection of hypertonic saline into the vastus medialis muscle (VM; left leg). Supersonic shear imaging was used to measure muscle shear elastic modulus as this is considered to be an index of muscle stress. Surface electromyography (EMG) was recorded bilaterally from six muscles to assess changes in neural strategies. During tasks with fewer degrees of freedom (knee extension and single leg squat task), there was no change in VM EMG amplitude or VM shear elastic modulus. In contrast, during the bilateral leg squat, VM (−32.9 ± 15.8%; P < 0.001) and vastus lateralis (−28.7 ± 14.8%; P < 0.001) EMG amplitude decreased during Pain. This decrease in activation was associated with reduced VM shear elastic modulus (−17.6 ± 23.3%; P = 0.029) and reduced force produced by the painful leg (−10.0 ± 10.2%; P = 0.046). This work provides evidence that when an obvious solution is available to decrease stress on painful tissue, this option is selected. It confirms the fundamental assumption that motor adaptations to pain aim to alter load on painful tissue to protect for further pain and/or injury. The lack of adaptation observed during force-matched tasks with fewer degrees of freedom might be explained by the limited potential to redistribute stress or a high cost induced by such a compensation.

Between-muscle differences in the adaptation to experimental pain

2014 ◽  
Vol 117 (10) ◽  
pp. 1132-1140 ◽  
Author(s):  
François Hug ◽  
Paul W. Hodges ◽  
Wolbert van den Hoorn ◽  
Kylie Tucker
Keyword(s):  
Elastic Modulus ◽  
Vastus Lateralis ◽  
Experimental Pain ◽  
Rectus Femoris ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Shear Elastic Modulus ◽  
Emg Amplitude ◽  
Extension Force ◽  
Muscle Stress

This study aimed to determine whether muscle stress (force per unit area) can be redistributed between individual heads of the quadriceps muscle when pain is induced into one of these heads. Elastography was used to measure muscle shear elastic modulus (an index of muscle stress). Electromyography (EMG) was recorded from vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF). In experiment I ( n = 20), participants matched a knee extension force, and thus any reduction of stress within the painful muscle would require compensation by other muscles. In experiment II ( n = 13), participants matched VL EMG amplitude and were free to vary external force such that intermuscle compensation would be unnecessary to maintain the experimental task. In experiments I and II, pain was induced by injection of hypertonic saline into VM or RF. Experiment III aimed to establish whether voluntary drive to the individual muscles could be controlled independently. Participants ( n = 13) were asked to voluntarily reduce activation of VM or RF while maintaining knee extension force. During VM pain, there was no change in shear elastic modulus ( experiments I and II) or EMG amplitude of VM ( experiment II). In contrast, RF pain was associated with a reduction in RF elastic modulus ( experiments I and II: −8 to −17%) and EMG amplitude ( experiment II). Participants could voluntarily reduce EMG amplitude of RF ( −26%; P = 0.003 ) but not VM ( experiment III). These results highlight between-muscle differences in adaptation to pain that might be explained by their function (monoarticular vs. biarticular) and/or the neurophysiological constraints associated to their activation.

Effect of vastus lateralis fatigue on load sharing between quadriceps femoris muscles during isometric knee extensions

2014 ◽  
Vol 111 (4) ◽  
pp. 768-776 ◽  
Author(s):  
Killian Bouillard ◽  
Marc Jubeau ◽  
Antoine Nordez ◽  
François Hug
Keyword(s):  
Elastic Modulus ◽  
Vastus Lateralis ◽  
Shear Wave Elastography ◽  
Rectus Femoris ◽  
Load Sharing ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Control Session ◽  
Shear Elastic Modulus ◽  
Control Load

The present study aimed to investigate the effects of selective fatigue (i.e., one muscle of the quadriceps) on load sharing strategies during submaximal knee extensions. Shear wave elastography was used to measure muscle shear elastic modulus, as this is considered to be an index of individual muscle force. Sixteen participants attended two experimental sessions that each involved six 10-s knee extensions at 20% of maximal voluntary contraction (MVC) followed by a sustained submaximal isometric knee extension at 20% of MVC, until task failure (Tlim). Between the 10-s contractions and Tlim, participants were required to rest (5 min) for the control session or underwent 5 min of electromyostimulation (EMS) on vastus lateralis (EMS session). Compared with the control session, vastus lateralis shear elastic modulus values were significantly lower after EMS considering both the start of Tlim (54.6 ± 11.8 vs. 68.4 ± 19.2 kPa; P = 0.011) and the entire Tlim contraction (59.0 ± 14.0 vs. 74.4 ± 20.3 kPa; P = 0.019). However, no significant differences were observed for the other recorded muscles (vastus medialis and rectus femoris; both P = 1), i.e., different patterns of changes were found between participants. In conclusion, this study demonstrates that prefatiguing a single agonist muscle does not lead to a consistent redistribution of load sharing among the quadriceps muscles between individuals. These results suggest that the central nervous system does not use a common principle among individuals to control load sharing when neuromuscular fatigue occurs.

Shear elastic modulus can be used to estimate an index of individual muscle force during a submaximal isometric fatiguing contraction

2012 ◽  
Vol 113 (9) ◽  
pp. 1353-1361 ◽  
Author(s):  
Killian Bouillard ◽  
François Hug ◽  
Arnaud Guével ◽  
Antoine Nordez
Keyword(s):  
Elastic Modulus ◽  
Muscle Force ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Load Sharing ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Activity Level ◽  
Shear Elastic Modulus ◽  
Individual Muscle

The present study was designed to determine whether fatigue alters the ability to estimate an index of individual muscle force from shear elastic modulus measurements ( experiment I), and to test the ability of this technique to highlight changes in load sharing within a redundant muscle group during an isometric fatiguing task ( experiment II). Twelve subjects participated in experiment I, which consisted of smooth linear torque ramps from 0 to 80% of maximal voluntary contraction (MVC) performed before and after an isometric fatigue protocol, beginning at 40% of MVC and stopped when the force production dropped below 30% of MVC. Although the relationships between modulus and torque were very similar for pre- and postfatigue [root mean square deviation (RMSdeviation) = 3.7 ± 2.6% of MVC], the relationships between electromyography activity level and torque were greatly altered by fatigue (RMSdeviation = 10.3 ± 2.6% of MVC). During the fatiguing contraction, shear elastic modulus provided a significantly lower RMSdeviation between measured torque and estimated torque than electromyography activity level (5.7 ± 0.9 vs. 15.3 ± 3.8% of MVC). Experiment II performed with eight participants consisted of an isometric knee extension at 25% of MVC sustained until exhaustion. Opposite changes in shear elastic modulus were observed between synergists (vastus medialis, vastus lateralis, and rectus femoris) of some participants, reflecting changes in load sharing. In conclusion, despite the fact that we did not directly estimate muscle force (in Newtons), this is the first demonstration of an experimental technique to accurately quantify relative changes in force in an individual human muscle during a fatiguing contraction.

Change in Shear Elastic Modulus of Thigh Muscle by Changing Muscle Length Using Ultrasound Shear Wave Elastography in Beagle Dogs

2019 ◽  
Vol 32 (06) ◽  
pp. 454-459 ◽  
Author(s):  
Miki Shimizu ◽  
Yu Ito
Keyword(s):  
Elastic Modulus ◽  
Shear Wave ◽  
Vastus Lateralis ◽  
Muscle Length ◽  
Shear Wave Elastography ◽  
Biceps Femoris ◽  
Percentage Change ◽  
Thigh Muscle ◽  
Beagle Dogs ◽  
Shear Elastic Modulus

Objectives This study investigated the relationship between the change in the shear elastic modulus and the change in muscle length using ultrasound shear wave elastography. Study Design Four thigh muscles, cranial part of the sartorius, vastus lateralis, biceps femoris and semitendinosus muscles, of 21 pelvic limbs in 12 clinically healthy Beagle dogs were used. The muscle length was estimated using a radiograph and the flexed and extended positions of the coxofemoral and stifle joints, respectively. The shear elastic modulus (kPa) was measured in two joint positions using ultrasound shear wave elastography. Shear elastic modulus was expressed as median of 10 consecutive measurements. The percentage change of elastic modulus was calculated from the shear elastic modulus in elongated condition and pre-elongated condition of muscle. Results The elastic modulus of all muscles increased when the muscle was elongated. The shear elastic modulus for both joint positions and the percentage change of the shear elastic modulus (%) in cranial part of the sartorius were highest in all muscles. Intra-observer correlation coefficient (1.2) was 0.75 to 0.96 and intra-observer correlation coefficients (2.2) was 0.46 to 0.96. Conclusion This study revealed that the shear elastic modulus of muscle was changed by the change in muscle length and increased when the muscle was elongated. Ultrasound shear wave elastography can be used to assess the elastic properties of canine muscle.

Hip Adduction Does not Affect VMO EMG Amplitude or VMO:VL Ratios during a Dynamic Squat Exercise

2006 ◽  
Vol 15 (3) ◽  
pp. 195-205 ◽  
Author(s):  
Michelle Boling ◽  
Darin Padua ◽  
J. Troy Blackburn ◽  
Meredith Petschauer ◽  
Christopher Hirth
Keyword(s):  
Outcome Measures ◽  
Knee Flexion ◽  
Healthy Subjects ◽  
Vastus Lateralis ◽  
Test Session ◽  
Surface Emg ◽  
Knee Extension ◽  
Emg Amplitude ◽  
Squat Exercise ◽  
History Of

Context:Clinicians commonly attempt to facilitate vastus medialis oblique (VMO) activity by instructing patients to squeeze a ball between their knees during squatting exercises.Objective:To determine whether VMO activation amplitude and the VMO to vastus lateralis (VL) activation ratio (VMO:VL) were altered when performing active hip adduction during a dynamic squat exercise.Design:Single test session.Participants:Fifteen healthy subjects, with no history of knee pain, volunteered for this study.Intervention:Surface EMG of the VMO, VL, and hip adductor (ADD) muscles were recorded while subjects performed 10 consecutive squats against their body weight through a range of 0° to 90° of knee flexion. Subjects performed the squat exercises during two different conditions: (1) active hip adduction and (2) no hip adduction.Main Outcome Measures:Average VMO EMG amplitude and VMO:VL ratio were determined during the knee flexion (0° to 90°) and knee extension (90° to 0°) phases of the squat exercise.Results:Active hip adduction did not significantly change VMO amplitude or VMO:VL ratio during the knee flexion or knee extension phases of the dynamic squat exercise.Conclusions:Based on these results, we conclude that VMO amplitude and the VMO: VL ratio are not influenced by performing active hip adduction during a dynamic squat exercise in healthy subjects.

scholarly journals Comparison of quadriceps muscle activation in exercises with different duration of concentric and eccentric contractions

2020 ◽  
Vol 37 (5) ◽  
pp. 291-297
Author(s):  
G Freire da Silva ◽  
F Douglas Tourino ◽  
RC Ribeiro Diniz ◽  
L Túlio de Lacerda ◽  
HC Martins Costa ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Muscle Activation ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Rectus Femoris ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Muscle Action ◽  
Emg Signal ◽  
Knee Extension Exercise

Aim: The objective of the present study was to compare the amplitude of the electromyographic (EMG) signal of the quadriceps muscle portions vastus medialis (VM), vastus lateralis (VL) and rectus femoris (RF) and the activation ratio (VM/VL, VM/RF and VL/RF) in protocols with different durations of concentric and eccentric muscular actions. Material and method: Twelve female volunteers performed the knee extensor exercise with two different protocols [1s for concentric muscle action and 5s for eccentric muscle action (1:5); 5s of concentric muscle action and 1s of eccentric muscle action (5:1)] and 3 sets of 6 repetitions, 180s of pause between each sets and a intensity of 50% of 1RM. The root mean square of the amplitude of the normalized EMG signal was calculated for each repetition in each series. Results: it was observed an increase in the activation of the VM and VL portions in equivalent repetitions of each series and for the VL portion, the 1: 5 protocol provided greater activation compared to the other protocol. No differences were found for muscles activation ratios VM/RF and VL/RF, being that for the VM/VL ratio there was only change at one repetition. Conclusion: The results suggest that the portions of the quadriceps muscle may present different EMG responses in similar protocols, but this fact may not interfere in the synergism between them. The reduced degrees of freedom of the knee extension exercise and the characteristics of the protocols adopted may be the elements that contributed to the limited alterations that occurred in the present study.

Skin Cooling Alters the Activation Patterns of Different Heads of the Quadriceps

2005 ◽  
Vol 30 (2) ◽  
pp. 127-139 ◽  
Author(s):  
Ryuta Kinugasa ◽  
Kazumasa Yoshida ◽  
Takayuki Watanabe ◽  
Kousuke Kuchiki ◽  
Akira Horii
Keyword(s):  
Isometric Force ◽  
Vastus Lateralis ◽  
Maximum Voluntary Contraction ◽  
Force Production ◽  
Transverse Relaxation Time ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Activation Patterns ◽  
Skin Cooling ◽  
The Right

The purpose of this study was to examine the effect of selective skin cooling over m. vastus lateralis (VL) on the activation patterns of quadriceps femoris muscle during knee extension exercise (KEE) using muscle function magnetic resonance imaging (mfMRI). The isometric force production of the right thigh was tested in 7 healthy young men at maximum voluntary contraction (MVC), and the transverse relaxation time (T2) value was taken from mfMR images at rest and immediately after KEE with 4 sets of 10 repetitions at a load equal to 60% of their 10-rep maximum, with and without skin cooling. The cooling was carried out by ice pack on the surface of the skin of the VL for 3 min before resting mfMRI and MVC tests, and before KEE, during KEE, and during the KEE rest intervals. The percent change in T2 of the m. vastus intermedius was significantly increased by skin cooling in comparison to the change without skin cooling, p < 0.05. This result suggests that skin cooling alters the activation pattern of the different heads of the quadriceps. Key words: cold, mfMRI, synergy, recruitment, neuromuscular plasticity

scholarly journals Electromyographic Comparison of Five Lower-Limb Muscles between Single- and Multi-Joint Exercises among Trained Men

2021 ◽  
pp. 56-61
Author(s):  
Nicolay Stien ◽  
Atle Hole Saeterbakken ◽  
Vidar Andersen
Keyword(s):  
Resistance Training ◽  
Vastus Lateralis ◽  
Gluteus Maximus ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Knee Extension ◽  
Knee Extensors ◽  
Vastus Medialis ◽  
Leg Press ◽  
Emg Amplitude

Resistance-training exercises can be classified as either single- or multi-joint exercises and differences in surface electromyography (EMG) amplitude between the two training methods may identify which muscles can benefit from either training modality. This study aimed to compare the surface EMG amplitude of five hip- and knee extensors during one multi-joint (leg press) and two single-joint exercises (knee extension and kickback). Fifteen resistance-trained men completed one familiarization session to determine their unilateral six repetitions maximum (6RM) in the three exercises. During the following experimental session, EMG amplitudes of the vastus lateralis, vastus medialis, rectus femoris, gluteus maximus and biceps femoris of the left leg were measured while performing three repetitions on their respective 6RM loads. The multi-joint exercise leg press produced higher EMG amplitude of the vastus lateralis (ES = 0.92, p = 0.003) than the single-joint exercise knee extension, whereas the rectus femoris demonstrated higher EMG amplitude during the knee extension (ES = 0.93, p = 0.005). The biceps femoris EMG amplitude was higher during the single-joint exercise kickback compared to the leg press (ES = 2.27, p < 0.001), while no significant differences in gluteus maximus (ES = 0.08, p = 0.898) or vastus medialis (ES = 0.056, p = 0.025 were observed between exercises. The difference in EMG amplitude between single- and multi-joint exercises appears to vary depending on the specific exercises and the muscle groups tested. Leg press is a viable and time-efficient option for targeting several hip- and knee extensors during resistance training of the lower limbs, but the single-joint exercises may be preferable for targeting the rectus femoris and biceps femoris.

scholarly journals Acute Effect of Active and Passive Static Stretching on Elastic Modulus of the Hamstrings

2018 ◽  
Vol 02 (06) ◽  
pp. E163-E170 ◽  
Author(s):  
Gakuto Nakao ◽  
Keigo Taniguchi ◽  
Masaki Katayose
Keyword(s):  
Elastic Modulus ◽  
Biceps Femoris ◽  
Acute Effect ◽  
Knee Extension ◽  
Static Stretching ◽  
Semitendinosus Muscle ◽  
Shear Elastic Modulus ◽  
Significant Difference ◽  
Long Head ◽  
Biceps Femoris Long Head

AbstractThe purpose of this study was to investigate differences in the acute effects of passive knee extension (PKE) and active knee extension (AKE) stretching on the shear elastic modulus of the hamstrings. In 20 healthy men, maximum knee extension (maximum range of motion [ROM]) and shear elastic modulus of the hamstrings (biceps femoris long head, semitendinosus, semimembranosus) were measured before (Pre) and after (Post) AKE and PKE stretching. The maximum ROM during stretching was measured. In both stretching methods, maximum ROM increased and the shear elastic modulus decreased (p<0.01), but no difference was found between the procedures. No significant difference was observed in the maximum ROM during stretching between the procedures (p=0.06). The shear elastic modulus was significantly lower in the biceps femoris long head and semimembranosus than in the semitendinosus muscle (p<0.05). Static stretching with PKE and AKE stretching showed an increase in maximum ROM and a decrease in hamstring elasticity, but no difference was found between the methods. Both stretching protocols were effective for reducing elasticity of the biceps femoris long head and semimembranosus.

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