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31.
32.
目的:建立腹直肌肌电图(EMG)运动单位动作电位(MUAP)各参数正常值。方法:测定109例正常人腹直肌EMG的MUAP的时限、波幅及多相波。结果:腹直肌EMG的MUAP参数分别为:波幅373.78±56.46μV,时限9.95±1.13 ms,多相波19.40%±1.52%。结论:腹直肌EMG各参数能可靠、稳定地测出,有助于脊髓胸段下运动神经元病变的检测。 相似文献
33.
K. B. Veiersted 《European journal of applied physiology》1991,62(2):91-98
Summary The main purpose of this study was to evaluate the reproducibility of electromyographic (EMG) measurements and specifically to test a calibration procedure with submaximal test contractions. Bipolar surface electrodes (20 mm fixed distance) were repositioned by a tracing sheet on both trapezius muscles, halfway between acromion and processus prominens. Submaximal test contractions were performed by keeping both arms straight abducted 90° and forward flexed 10° for 15-s periods. The arm position could be precisely reproduced in the frontal plane, but deviated forwards by 4° in the horizontal plane, where the sensitivity of the EMG response to arm position was lowest. The electrodes were repositioned within a radius of 3 mm with a probability of 90%. Large deviations in the EMG response were found within this radius and a significant depression of the EMG response was recorded over the middle part of the muscle (the innervation zone?). This change in sensitivity of the EMG response with electrode position occurred in parallel for the test and maximal contractions. The total coefficient of variation was estimated to be 23% for recurrent EMG measurements using the calibration procedure described. 相似文献
34.
Björn Gerdle Jessica Elert Karin Henriksson-Larsén 《European journal of applied physiology》1989,58(6):666-673
Summary Peak torque, work, mean power and electromyographic (EMG) activity were recorded for each of 150 repeated isokinetic maximal shoulder flexions (45°–90°) in 23 healthy females. From the EMG signals of trapezius, deltoid, infraspinatus and biceps brachii the mean power frequency and the signal amplitude were determined in real time. The mechanical output showed a steep decrease during the first 40 contractions, followed by a plateau maintained until the end. In all muscles, except the biceps brachii, significant decreases in mean power frequency occurred during the first 40 contractions, showing a tendency to stabilize around the same absolute frequency value. Signal amplitude increased in the trapezius, the deltoid and the infraspinatus, but was constant in the biceps brachii. For some individuals rather high EMG activity was recorded in the muscles during the time the arm was supposed to be passively extended to the starting position, and this was found to be associated with lower strength and endurance levels. Longitudinal analyses showed that the mean power frequencies correlated better than the signal amplitudes with the three mechanical variables. The results suggest that the initial steep decrease in mechanical performance and mean power frequency is caused by fatiguing of type 2 motor units. 相似文献
35.
Independent coactivation of shoulder and elbow muscles 总被引:1,自引:0,他引:1
Paul L. Gribble D. J. Ostry 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1998,123(3):355-360
The aim of this study was to examine the possibility of independent muscle coactivation at the shoulder and elbow. Subjects
performed rapid point-to-point movements in a horizontal plane from different initial limb configurations to a single target.
EMG activity was measured from flexor and extensor muscles acting at the shoulder (pectoralis clavicular head and posterior
deltoid) and elbow (biceps long head and triceps lateral head) and flexor and extensor muscles acting at both joints (biceps
short head and triceps long head). Muscle coactivation was assessed by measuring tonic levels of electromyographic (EMG) activity
after limb position stabilized following the end of the movements. It was observed that tonic EMG levels following movements
to the same target varied as a function of the amplitude of shoulder and elbow motion. Moreover, for the movements tested
here, the coactivation of shoulder and elbow muscles was found to be independent – tonic EMG activity of shoulder muscles
increased in proportion to shoulder movement, but was unrelated to elbow motion, whereas elbow and double-joint muscle coactivation
varied with the amplitude of elbow movement and were not correlated with shoulder motion. In addition, tonic EMG levels were
higher for movements in which the shoulder and elbow rotated in the same direction than for those in which the joints rotated
in opposite directions. In this respect, muscle coactivation may reflect a simple strategy to compensate for forces introduced
by multijoint limb dynamics.
Received: 7 July 1998 / Accepted: 28 July 1998 相似文献
36.
目的探讨旋后肩法用于肩难产产妇,对其产后盆底肌功能的改善作用。 方法选择2018年7月至2020年1月,在宁波市妇女儿童医院采用旋后肩法完成肩难产助产的28例产妇为研究对象,并纳入研究组。选取同期在本院分娩,采用耻骨联合上加压法完成肩难产助产的25例产妇纳入对照组。采用表面肌电图(sEMG),获取2组产妇分娩8周后盆底肌收缩运动肌电值。采用成组t检验,对2组产妇一般临床资料、盆底sEMG检测结果进行统计学分析。采用χ2检验,对2组产妇分娩巨大儿所占比例等进行统计学分析。本研究遵循的程序符合病例收集医院伦理委员会制定的伦理学标准,得到该委员会批准[审批文号:[2018]伦审字(28)号]。与所有受试者签署临床研究知情同意书。 结果①2组产妇身高、体重,分娩时人体质量指数(BMI)、孕龄、年龄等一般临床资料比较,差异均无统计学意义(P>0.05)。②2组产妇分娩新生儿的出生体重和巨大儿所占比例分别比较,差异亦均无统计学意义(P>0.05)。③研究组产妇前基线值、快肌收缩最大值、混合肌收缩最大值、混合肌收缩平均值、耐力肌收缩平均值、后基线值分别为(1.4±0.3) μV、(23.8±5.5) μV、(19.9±3.4) μV、(17.2±2.9) μV、(13.7±3.0) μV、(1.3±0.3) μV,均超过对照组的(1.3± 0.3) μV、(20.6±4.4) μV、(17.7±3.3) μV、(14.2±4.1) μV、(11.8±3.4) μV、(1.1±0.3) μV,并且差异均有统计学意义(P<0.05)。而2组产妇耐力肌收缩最大值比较,差异无统计学意义(P>0.05)。 结论旋后肩法用于肩难产产妇助产,较传统耻骨联合上加压法,可改善产妇产后短期内的盆底肌功能。 相似文献
37.
Functionally complex muscles of the cat hindlimb 总被引:2,自引:0,他引:2
C. M. Chanaud J. M. Macpherson 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1991,85(2):271-280
The biceps femoris (BF) muscle is divided into three neuromuscular compartments defined by the innervation patterns of the main nerve branches (English and Weeks 1987). The goals of this study were i) to determine how different regions of the biceps femoris muscle are activated in the intact cat during a broad range of limb movements evoked by perturbations of stance posture, and ii) to determine the relationship between the anatomical compartments of biceps femoris and the functional units as defined in this task. Cats were trained to stand on a moveable platform with each paw on a triaxial force plate. The animal's stance was perturbed by linear translation of the platform in each of sixteen different directions in the horizontal plane. EMG activity was recorded from eight sites across the width of the left biceps femoris muscle. During quiet stance only the anterior compartment was tonically active, presumably contributing to hip extensor torque in the maintenance of stance. During platform translation, evoked EMG activity was recorded from each electrode pair for a wide range of directions of perturbation; as direction changed progressively, the amplitude of evoked activity from any electrode pair increased to a maximum and then decreased. When the EMG amplitude was plotted in polar coordinates as a function of translation direction, the region of response formed a petal shaped area in the horizontal plane, termed the EMG tuning curve. The compartments of the BF muscle were not activated homogeneously. The tuning curve of the anterior BF compartment was similar to that of other hip extensors, and coincided with the region of postero-lateral force production by the hindlimb against the support. The tuning curve of the middle BF compartment was shifted in a counterclockwise direction from that of the anterior compartment, but overlapped extensively with it; the middle BF tuning curve was similar to that of anterior gracilis. The tuning curve of the posterior biceps compartment was rotated further counterclockwise and overlapped very little with that of the middle BF compartment. The posterior BF was activated in a pattern similar to that of other knee flexors. The functional units of BF activation were not identical with the neuromuscular compartments defined by the main nerve branches. As direction of the perturbation changed, the region of BF that was activated moved progressively across the muscle. This progression of the active region was continuous across BFa and BFm, whereas there was a jump, or discontinuity at the border between BFm and BFp.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
38.
Terry J. Housh Herbert A. deVries Glen O. Johnson Sharon A. Evans Gerald D. Tharp Dona J. Housh Rommie J. Hughes 《European journal of applied physiology》1990,60(5):391-394
Summary The purpose of this investigation was to determine the effect of glycogen depletion and super-compensation on the physical working capacity at the fatigue threshold (PWCFT). Ten adult males (mean age 23 years, SD 3) volunteered as subjects for this study. During the first laboratory visit the subjects performed a maximal bicycle ergometer test for the determination of maximum oxygen consumption
. Between 48 and 72 h later, the subjects pedaled to exhaustion at a power output which corresponded to a mean of 76% of
(range, 72–80%) for the purpose of glycogen depletion. For the next 3 days, the subjects were fed a 10.5 MJ · day–1 low carbohydrate diet which consisted of 7.5% carbohydrates, 22.0% protein and 70.5% fat. The subjects then performed an incremental cycle ergometer test to the onset of fatigue or PWCFT, which was estimated from integrated electromyographic voltages of the vastus lateralis muscle. For the next 3 days the subjects were fed a 10.5 MJ high carbohydrate diet which consisted of 72.2% carbohydrates, 12.4% protein and 15.4% fats for the purpose of glycogen supercompensation. The subjects then performed a second PWCFT test. A paired t-test indicated that there was no significant (p > 0.05) difference between the means of the PWCFT values (depletion 246 W, SD 30; supercompensation 265 W, SD 28) and they were highly correlated atr=0.884. The results of this investigation suggested that the methods commonly used to affect glycogen depletion or supercompensation had no effect on PWCFT. 相似文献
39.
40.
Peter J. H. Jongen Hendrik M. Vingerhoets Karin Roeleveld Dick F. Stegeman 《Journal of neurology》1996,243(1):79-85
Automatic decomposition electromyography (ADEMG) is a commercially available software package with installed reference values that enables the objective measurement of motor unit action potentials (MUAPs). To assess the diagnostic yield of this package in idiopathic inflammatory myopathies (IIM) we performed biceps brachii ADEMG in 17 patients with polymyositis, dermatomyositis and inclusion body myositis. Results were compared with those in 12 controls, and with the results of conventional EMG of the biceps and other muscles. Decreased mean values for MUAP duration occurred significantly more frequently in IIM patients than in controls; other MUAP characteristics did not differ. In IIM patients, decreased mean amplitude and increased mean number of turns occurred significantly less frequently on ADEMG than did corresponding abnormalities on conventional biceps EMG. Decreased mean values for duration and amplitude, and increased mean values for number of turns were seen significantly less often on ADEMG than corresponding abnormalities on conventional EMG of four different, individually chosen muscles. Overall evaluation of ADEMG resulted in a diagnosis of possible myopathy in 1 and probable myopathy in 8 patients, whereas overall evaluation of conventional EMG led to a diagnosis suggestive of IIM in 13 patients. We conclude that, although measurement of mean MUAP duration might be valuable in IIM diagnosis, our results do not favour the use of biceps brachii ADEMG and the installed reference values for the diagnosis of IIM. We suggest modifications to improve ADEMG's applicability. 相似文献