CHARACTERIZATION OF FINGER ISOMETRIC FORCE PRODUCTION WITH MAXIMUM POWER OF SURFACE ELECTROMYOGRAPHY

2009 ◽  
Vol 21 (03) ◽  
pp. 193-199 ◽  
Author(s):  
Wensheng Hou ◽  
Xiaoying Wu ◽  
Jun Zheng ◽  
Li Ma ◽  
Xiaolin Zheng ◽  
...  
Keyword(s):  
Surface Electromyography ◽  
Force Production ◽  
Neuromuscular Control ◽  
Maximum Power ◽  
Ar Model ◽  
Force Level ◽  
Hand Muscles ◽  
Significant Difference ◽  
Target Force ◽  
Hand Muscle

Finger's action has been controlled by both intrinsic and extrinsic hand muscles. Characterizing the finger action with the activations of hand muscles could be useful for evaluating the neuromuscular control strategy of finger's motor functions. This study is designed to explore the correlation of isometric fingertip force production and frequency-domain features of surface electromyography (sEMG) recorded on extrinsic hand muscles. To this end, 13 subjects (five male and eight female university students) have been recruited to conduct a target force-tracking task. Each subject is required to produce a certain level of force with either the index or middle fingertip to match the pseudo-random ordered target force level (4N, 6N, or 8N) as accurate as possible. During the finger force production process, the sEMG signals are recorded on two extrinsic hand muscles: flex digitorum superficials (FDS) and extensor digitorum (ED). For each sEMG trail, the power spectrum is estimated with the autoregressive (AR) model and from which the maximum power is obtained. Our experimental results reveal three findings: (1) the maximum power increases with the force level regardless of the force producing finger (i.e. index or middle) and the extrinsic hand muscle (i.e. FDS or ED). (2) The sEMG maximum power of index finger is significantly lower than that of the middle finger under the same force level and extrinsic hand muscle. (3) No significant difference can be found between the maximum powers of FDS and ED. The results indicate that the activations of the extrinsic muscles are affected by both the force level and the force producing finger. Based on our findings, the sEMG maximum power of the extrinsic hand muscles could be used as a key parameter to describe the finger's actions.

IMPACT OF FINGERTIP ACTIONS ON TOTAL POWER OF SURFACE ELECTROMYOGRAPHY FROM EXTRINSIC HAND MUSCLES

2012 ◽  
Vol 12 (03) ◽  
pp. 1250056
Author(s):  
D. D. YANG ◽  
W. S. HOU ◽  
X. Y. WU ◽  
J. ZHENG ◽  
X. L. ZHENG ◽  
...  
Keyword(s):  
Surface Electromyography ◽  
Index Finger ◽  
Statistical Significance ◽  
Middle Finger ◽  
Total Power ◽  
Force Level ◽  
Hand Muscles ◽  
Fingertip Force ◽  
Hand Muscle ◽  
The Relationship

Quantizing the relationship between finger force and multitendoned extrinsic hand muscles could be useful for understanding the control strategies that underlie the coordination of finger movements and forces. The objective of this study is to explore the relationship of fingertip force production and total power of surface electromyography (sEMG) recorded on extrinsic hand muscles under isometric voluntary contraction. Thirteen healthy volunteers were recruited to participate in this study. In the designed force-tracking tasks, all volunteers were required to produce a certain force with either index finger or middle finger to match the target force for 5 s. Meanwhile, the sEMG signals were acquired from two extrinsic hand muscles: extensor digitorum (ED) and flexor digitorum superficialis (FDS). For each trial, sEMG of the effective force segment was extracted; then, the power spectrum was estimated based on autoregressive (AR) model and from which the corresponding total power of sEMG was computed. The experimental results reveal that the total power of sEMG linearly increases with force level regardless of the task finger and extrinsic hand muscle. It is also found that the total power obtained from index finger is significantly less than that of middle finger for FDS at the same force level (p < 0.05), while this kind of statistical significance cannot be found for ED. However, with respect to the measurement of total power, the type of extrinsic hand muscle has not exhibited significantly different contribution to the task finger under a certain fingertip force level. The findings of this study indicate that the total power of the extrinsic hand muscle's sEMG can be used to characterize finger's activities.

A STUDY OF MODELS FOR HANDGRIP FORCE PREDICTION FROM SURFACE ELECTROMYOGRAPHY OF EXTENSOR MUSCLE

2009 ◽  
Vol 21 (02) ◽  
pp. 81-88 ◽  
Author(s):  
Wensheng Hou ◽  
Xiaolin Zheng ◽  
Yingtao Jiang ◽  
Jun Zheng ◽  
Chenglin Peng ◽  
...  
Keyword(s):  
Root Mean Square ◽  
Surface Electromyography ◽  
Random Sequence ◽  
Maximum Voluntary Contraction ◽  
Force Production ◽  
Voluntary Contraction ◽  
Mean Square ◽  
Force Level ◽  
Force Output ◽  
Mean Square Errors

Force production involves the coordination of multiple muscles, and the produced force levels can be attributed to the electrophysiology activities of those related muscles. This study is designed to explore the activity modes of extensor carpi radialis longus (ECRL) using surface electromyography (sEMG) at the presence of different handgrip force levels. We attempt to compare the performance of both the linear and nonlinear models for estimating handgrip forces. To achieve this goal, a pseudo-random sequence of handgrip tasks with well controlled force ranges is defined for calibration. Eight subjects (all university students, five males, and three females) have been recruited to conduct both calibration and voluntary trials. In each trial, sEMG signals have been acquired and preprocessed with Root–Mean–Square (RMS) method. The preprocessed signals are then normalized with amplitude value of Maximum Voluntary Contraction (MVC)-related sEMG. With the sEMG data from calibration trials, three models, Linear, Power, and Logarithmic, are developed to correlate the handgrip force output with the sEMG activities of ECRL. These three models are subsequently employed to estimate the handgrip force production of voluntary trials. For different models, the Root–Mean–Square–Errors (RMSEs) of the estimated force output for all the voluntary trials are statistically compared in different force ranges. The results show that the three models have different performance in different force ranges. Linear model is suitable for moderate force level (30%–50% MVC), whereas a nonlinear model is more accurate in the weak force level (Power model, 10%–30% MVC) or the strong force level (Logarithmic model, 50%–80% MVC).

scholarly journals Effect of bilateral contraction on the ability and accuracy of rapid force production at submaximal force level

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247099
Author(s):  
Yoichi Ohta
Keyword(s):  
Grip Force ◽  
Force Production ◽  
Standing Position ◽  
Voluntary Contraction ◽  
Force Level ◽  
Noticeable Effect ◽  
Force Ratio ◽  
Significant Difference ◽  
Small Effect Size ◽  
The Difference

The present study aims to clarify the effects of bilateral contraction on the ability and accuracy of rapid force production at the submaximal force level. Eleven right-handed participants performed rapid gripping as fast and precisely as they could in unilateral (UL) and bilateral (BL) contractions in a standing position. Participants were required to impinge a grip force of 30% and 50% of their maximal voluntary contraction (MVC). Ability and accuracy of rapid force production were evaluated using the rate of force development (RFD) and force error, respectively. The data analysis did not observe a significant difference in the RFD between UL and BL contractions in both 30% (420±86 vs. 413±106%MVC/s, p = 0.34) and 50% of MVC (622±84 vs. 619±103%MVC/s, p = 0.77). Although the RFD to peak force ratio (RFD/PF) in BL contraction was lower than in UL in 30% of MVC (12.8±2.8 vs. 13.4±2.7, p = 0.003), it indicated a small effect size (d = 0.22) of the difference between UL and BL in RFD/PF. The absolute force error of BL contraction was higher than of UL contraction in 30% (4.67±2.64 vs. 3.64±1.13%MVC, p = 0.005) and 50% of MVC (5.53±2.94 vs. 3.53±0.71%MVC, p = 0.009). In addition, medium and large effect sizes were observed in absolute force error from 30% (d = 0.51) and 50% of MVC (d = 0.94), respectively. In conclusion, results indicated that the bilateral contraction reduced in the ability and accuracy of rapid force production at the submaximal force level. Nevertheless, the present results suggest that the noticeable effect of bilateral contraction is more prominent on the accuracy than in the ability of rapid force production at the submaximal force level.

scholarly journals Force-Independent Distribution of Correlated Neural Inputs to Hand Muscles During Three-Digit Grasping

2010 ◽  
Vol 104 (2) ◽  
pp. 1141-1154 ◽  
Author(s):  
Brach Poston ◽  
Alessander Danna-Dos Santos ◽  
Mark Jesunathadas ◽  
Thomas M. Hamm ◽  
Marco Santello
Keyword(s):  
Muscle Activation ◽  
Force Production ◽  
Emg Activity ◽  
Muscle Coordination ◽  
Single Digit ◽  
Hand Muscles ◽  
Hand Muscle ◽  
Grasp Force ◽  
Independent Distribution ◽  
Coordination Patterns

The ability to modulate digit forces during grasping relies on the coordination of multiple hand muscles. Because many muscles innervate each digit, the CNS can potentially choose from a large number of muscle coordination patterns to generate a given digit force. Studies of single-digit force production tasks have revealed that the electromyographic (EMG) activity scales uniformly across all muscles as a function of digit force. However, the extent to which this finding applies to the coordination of forces across multiple digits is unknown. We addressed this question by asking subjects ( n = 8) to exert isometric forces using a three-digit grip (thumb, index, and middle fingers) that allowed for the quantification of hand muscle coordination within and across digits as a function of grasp force (5, 20, 40, 60, and 80% maximal voluntary force). We recorded EMG from 12 muscles (6 extrinsic and 6 intrinsic) of the three digits. Hand muscle coordination patterns were quantified in the amplitude and frequency domains (EMG–EMG coherence). EMG amplitude scaled uniformly across all hand muscles as a function of grasp force (muscle × force interaction: P = 0.997; cosines of angle between muscle activation pattern vector pairs: 0.897–0.997). Similarly, EMG–EMG coherence was not significantly affected by force ( P = 0.324). However, coherence was stronger across extrinsic than that across intrinsic muscle pairs ( P = 0.0039). These findings indicate that the distribution of neural drive to multiple hand muscles is force independent and may reflect the anatomical properties or functional roles of hand muscle groups.

Continuous theta-burst stimulation to primary motor cortex reveals asymmetric compensation for sensory attenuation in bimanual repetitive force production

2013 ◽  
Vol 110 (4) ◽  
pp. 872-882 ◽  
Author(s):  
Amanda S. Therrien ◽  
James Lyons ◽  
Ramesh Balasubramaniam
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Force Production ◽  
Force Level ◽  
Theta Burst Stimulation ◽  
Burst Stimulation ◽  
Task Goal ◽  
Target Force ◽  
Theta Burst ◽  
Continuous Theta Burst Stimulation

Studies of fingertip force production have shown that self-produced forces are perceived as weaker than externally generated forces. This is due to mechanisms of sensory reafference where the comparison between predicted and actual sensory feedback results in attenuated perceptions of self-generated forces. Without an external reference to calibrate attenuated performance judgments, a compensatory overproduction of force is exhibited. It remains unclear whether the force overproduction seen in the absence of visual reference stimuli differs when forces are produced bimanually. We studied performance of two versions of a bimanual sequential force production task compared with each hand performing the task unimanually. When the task goal was shared, force series produced by each hand in bimanual conditions were found to be uncorrelated. When the bimanual task required each hand to reach a target force level, we found asymmetries in the degree of force overproduction between the hands following visual feedback removal. Unilateral continuous theta-burst stimulation of the left primary motor cortex yielded a selective reduction of force overproduction in the hand contralateral to stimulation by disrupting sensory reafference processes. While variability was lower in bimanual trials when the task goal was shared, this influence of hand condition disappeared when the target force level was to be reached by each hand simultaneously. Our findings strengthen the notion that force control in bimanual action is less tightly coupled than other mechanisms of bimanual motor control and show that this effector specificity may be extended to the processing and compensation for mechanisms of sensory reafference.

Altered neuromuscular control of a hand muscle in chronic rotator cuff tears

2009 ◽  
Vol 130 (5) ◽  
pp. 705-710 ◽  
Author(s):  
Alexander Berth ◽  
Géza Pap ◽  
Wolfram Neumann ◽  
Friedemann Awiszus
Keyword(s):  
Rotator Cuff ◽  
Neuromuscular Control ◽  
Rotator Cuff Tears ◽  
Hand Muscle

Neuromuscular drive and force production are not altered during bilateral contractions

1998 ◽  
Vol 84 (1) ◽  
pp. 200-206 ◽  
Author(s):  
J. M. Jakobi ◽  
E. Cafarelli
Keyword(s):  
Motor Unit ◽  
Force Production ◽  
Young Male ◽  
Neuromuscular Control ◽  
Force Generation ◽  
Isometric Contractions ◽  
Firing Rates ◽  
Significant Limitation ◽  
Motor Unit Firing ◽  
Male Subjects

Jakobi, J. M., and E. Cafarelli. Neuromuscular drive and force production are not altered during bilateral contractions. J. Appl. Physiol. 84(1): 200–206, 1998.—Several investigators have studied the deficit in maximal voluntary force that is said to occur when bilateral muscle groups contract simultaneously. A true bilateral deficit (BLD) would suggest a significant limitation of neuromuscular control; however, some of the data from studies in the literature are equivocal. Our purpose was to determine whether there is a BLD in the knee extensors of untrained young male subjects during isometric contractions and whether this deficit is associated with a decreased activation of the quadriceps, increased activation of the antagonist muscle, or an alteration in motor unit firing rates. Twenty subjects performed unilateral (UL) and bilateral (BL) isometric knee extensions at 25, 50, 75, and 100% maximal voluntary contraction. Total UL and BL force (Δ3%) and maximal rate of force generation (Δ2.5%) were not significantly different. Total UL and BL maximal vastus lateralis electromyographic activity (EMG; 2.7 ± 0.28 vs. 2.6 ± 0.24 mV) and coactivation (0.17 ± 0.02 vs. 0.20 ± 0.02 mV) were also not different. Similarly, the ratio of force to EMG during submaximal UL and BL contractions was not different. Analysis of force production by each leg in UL and BL conditions showed no differences in force, rate of force generation, EMG, motor unit firing rates, and coactivation. Finally, assessment of quadriceps activity with the twitch interpolation technique indicated no differences in the degree of voluntary muscle activation (UL: 93.6 ± 2.51 Hz, BL: 90.1 ± 2.43 Hz). These results provide no evidence of a significant limitation in neuromuscular control between BL and UL isometric contractions of the knee extensor muscles in young male subjects.

scholarly journals Difference between Right and Left Facial Surface Electromyography in Healthy People

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Bo-Hyun Kim ◽  
Kyeong Han Kim ◽  
Lak-Hyung Kim ◽  
Jong-Uk Kim ◽  
Tae-Han Yook
Keyword(s):  
Surface Electromyography ◽  
Nerve Palsy ◽  
Facial Nerve Palsy ◽  
Asymmetry Index ◽  
Healthy People ◽  
Mean Square ◽  
Frontalis Muscle ◽  
Significant Difference ◽  
Orbicularis Oris Muscle ◽  
Age And Sex

Introduction. The study was to see whether there were differences in values of facial surface electromyography in subjects of good heath by muscles, age, and sex. Methods. It draws ratio between lower value and higher value (R-LV/HV) and asymmetry index (AI), based on root mean square (RMS) from measurement of facial surface electromyography (sEMG) in 154 people of healthy people (male:female = 70:84) aging between more than 20 and less than 70. Results. For R-LV/HV, it averages 81.70±14.60% on frontalis muscle, 73.74±19.12% on zygomaticus muscle, and 79.72±14.77% on orbicularis oris muscle. With analysis of the AI average was 10.87±10.14% on frontalis muscle, 16.71±14.79% on zygomaticus muscle, and 12.10±10.05% on orbicularis oris muscle. Both values were statistically significant in three parts of muscles as shown. Both of R-LV/HV and AI show no statistically significant difference on age and sex (p>0.05). Conclusions. It could provide basic data for the future diagnosis of facial nerve palsy patients by measuring facial sEMG values for healthy people.

scholarly journals Function, strength, and muscle activation of the shoulder complex in Crossfit practitioners with and without pain: a cross-sectional observational study

2022 ◽  
Vol 17 (1) ◽  
Author(s):  
Elisa Raulino Silva ◽  
Nicola Maffulli ◽  
Filippo Migliorini ◽  
Gilmar Moraes Santos ◽  
Fábio Sprada de Menezes ◽  
...  
Keyword(s):  
Shoulder Pain ◽  
Surface Electromyography ◽  
Shoulder Joint ◽  
Muscle Activation ◽  
National Registry ◽  
Kinetic Chain ◽  
Balance Test ◽  
Cross Sectional ◽  
Significant Difference ◽  
Lower Trapezius

Abstract Background The shoulder joint is the most commonly injured joint in CrossFit practitioners, because of the high intensity and loads associated with this sport. Despite the large number of clinical cases, there is a shortage of studies that investigate influence of biomechanical aspects of upper limbs' injuries on CrossFit practitioners. This study hypothesized that there would be a difference in function, strength, and muscle activation between Crossfit practitioners with and without shoulder pain. Methods We divided 79 Crossfit practitioners into two groups according to whether they reported pain (n = 29) or no pain (n = 50) in the shoulder during Crossfit training. Muscle function, strength, and activation were assessed using the Disability Arm, Shoulder and Hand function questionnaire, Upper Quarter Y Balance Test and Closed Kinetic Chain Upper Extremity Stability Test shoulder tests, isometric muscle strength assessment by manual dynamometry and muscle activation by surface electromyography and pain report. Results The function based on questionnaire was associated with pain (p = 0.004). We observed a statistically significant difference between the two groups only in the surface electromyography activity of the lower trapezius, and in the variables of shoulder pain and function (p = 0.038). Conclusion Crossfit practitioners with shoulder pain occurring during training showed good function and stability of the shoulder joint, but there was a reduction in the activation of stabilizing muscles, especially the lower trapezius. Trial registration Registro Brasileiro de Ensaios Clinico (Brasilian National Registry) with the ID: RBR-2gycyv.

scholarly journals Complexity of Knee Neuromuscular Control in Uninjured Physically Active Adults: Right/Left and Dominant/Nondominant Asymmetry Analyses

2021 ◽  
Author(s):  
Nicholas Clark ◽  
Jamie Pethick
Keyword(s):  
Motor Neurons ◽  
Neuromuscular Control ◽  
Approximate Entropy ◽  
Knee Extension ◽  
Fluctuation Analysis ◽  
Temporal Behavior ◽  
Individual Level ◽  
Significant Difference ◽  
Clinically Significant ◽  
The Right

Context: Motor pathways include upper motor-neurons from the cerebrum and brainstem and lower motor-neurons from the spinal cord. Together, these physiological components are effectors of knee neuromuscular control. Because multiple components are involved, each with an output that is asynchronous to the others, ‘whole-system’ output is characterized by irregular temporal behavior and signal fluctuations. The irregular temporal behavior of physiological signals is analyzed using ‘complexity’. Complexity-based measures reflect the ability to adapt motor output rapidly and accurately in response to external perturbations and provide physiological information missed by magnitude-based (variability) measures.Objective: To characterize side-to-side symmetry of knee neuromuscular control (sub-maximal isometric knee extension constant-force task) using variability (coefficient of variation [CV%]) and complexity (approximate entropy [ApEn], detrended fluctuation analysis [DFA α]) measures.Design: Cross-sectional.Setting: Laboratory.Patients or Other Participants: Sixteen (male/female n=11/5; age 24.0±5.3yr; height 1.74±0.08m; body-mass 68.3±11.1kg).Main Outcome Measure(s): Right/left and dominant/nondominant group-level (t-test) and individual-level (absolute-asymmetry [%]) comparisons. A limb-symmetry-index was calculated for each variable and clinically-significant absolute-asymmetry defined (&gt;15%). Clinically-significant absolute-asymmetry prevalence (%) was computed for each variable.Results: The only significant side-to-side difference was for right/left DFA α (P=.000). Maximum absolute-asymmetries were (right/left, dominant/nondominant): CV 18.2%, 18.0%; ApEn 34.5%, 32.3%; DFA α 4.9%, 5.0%. Clinically-significant absolute-asymmetry prevalence was (right/left, dominant/nondominant): CV 43.8%, 43.8%; ApEn 62.5%, 50.0%; DFA α 0.0%, 0.0%.Conclusions: Different side-to-side comparison methods yield different findings. Large proportions of participants demonstrated wide ranges of side-to-side absolute-asymmetries. The finding of a significant difference for the right/left DFA α comparison but not for the right/left ApEn comparison suggests that different complexity variables assess different aspects of complexity. Consideration for how side-to-side comparisons are performed (right/left, dominant/nondominant) is required. Approximate entropy and DFA α assess different aspects of complexity and both should be used alongside other traditional magnitude-based measures when studying knee neuromuscular control.

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