前交叉韧带损伤患者及健康人膝关节屈肌协同收缩的对比研究

目的:探索一种适合评估膝关节稳定功能的电生理评估指标。方法:前交叉韧带损伤(ACLD)患者33例为ACLD组,健康志愿者29例为对照组,用ME6000表面肌电仪器记录终末伸膝最大等长收缩和上台阶运动过程中伸肌(股外侧肌、股内侧肌)、屈肌(股二头肌、半腱肌)表面肌电信号,分析测试肌肉的积分肌电平均值、屈肌协同收缩程度及协同收缩率。结果:前交叉韧带损伤患者终末伸膝最大等长收缩和上台阶运动的屈肌协同收缩率明显高于健肢及正常对照组(P<0.05),伸肌收缩降低(P<0.05),屈肌协同收缩程度增加(P<0.05)。结论:伸膝运动中,前交叉韧带损伤患者通过降低伸肌的主动收缩,增加屈肌协同收缩来提高关节稳定性,屈肌的协同收缩率可以反映膝关节的稳定功能。     

膝关节屈肌和伸肌等速向心、等速离心及等长测试的研究

本文通过运用Ｃｙｂｅｘ－６０００型等速测力系统对２５名健康男青年膝屈肌和伸肌进行等速向心、等速离心及等长测试，来比较膝肌肉向心收缩、离心收缩和等长收缩的功能，并探讨其相互间的关系。结果表明：等速测试时，膝屈肌和伸肌离心收缩的肌力明显大于向心收缩。在膝屈曲６０°时，离心收缩和等长收缩的肌力同样明显大于向心收缩，但离心收缩与等长收缩相比无显著性差异。随运动速度增加，屈肌和伸肌向心收缩的肌力明显下降，而离心收缩的肌力无明显变化。     

肌肉运动点电刺激治疗中风后手功能障碍的临床疗效

 目的 观察肌肉运动点电刺激与常规针刺法治疗中风后手功能障碍的临床疗效差异。方法 选取武警特色医学中心中风后手功能障碍患者60例,随机分为针刺组和肌肉运动点电刺激组,每组30例。在西医常规治疗基础上,针刺组采用手局部取穴的单纯针刺治疗,电刺激组采用指伸肌、拇长展肌、指浅屈肌及拇长屈肌肌肉运动点电刺激治疗,1次/d;均治疗2周后采用Brunnstrom手运动功能评定量表,Fugl-Meyer上肢运动功能评定表,CSS临床神经功能缺损程度表进行评定并评价临床疗效。结果 两组治疗后Brunnstrom评定量表、Fugl-Meyer评分及CSS评分较治疗前均有改善,电刺激组较针刺组改善更明显,差异具有统计学意义。结论 两种方法治疗中风后手功能障碍均可提高患手的肌力与活动能力,促进手功能恢复,但肌肉运动点电刺激治疗的疗效较常规针刺法更优。     

悬吊大鼠后肢骨骼肌等长收缩功能变化的动态特征

目的观测模拟失重1、2和4周大鼠比目鱼肌与趾长伸肌收缩性能的变化,并分析萎缩比目鱼肌收缩性能变化的可能机制.方法采用离体骨骼肌肌条灌流技术,观测比目鱼肌与趾长伸肌的等长收缩功能.结果悬吊1周大鼠比目鱼肌即出现萎缩,悬吊2周与4周进一步萎缩,在各时间点两组的差别均具有显著性或非常显著性意义.比目鱼肌等长收缩的最大张力在悬吊第1周仅呈降低趋势[对照组(1.76±0.18)g/mm2,悬吊组(1.46±0.26)g/mm2,P＞0.05],第2周的降低具有显著性意义[(1.25±0.09)g/mm2,P＜0.05],第4周则进一步降低[(0.90±0.06)g/mm2,P＜0.01].悬吊1周组大鼠趾长伸肌的最大张力未改变,2周与4周组的降低具有非常显著性意义(P＜0.01).悬吊1、2和4周组大鼠比目鱼肌等长收缩达到最大张力一半的时间与同步对照组相比,两组间的差别均无显著性意义(P＞0.05),但是,悬吊1与2周组达到最大张力的时间与从张力峰值到舒张75%的时间缩短(P＜0.05),悬吊4周组则进一步缩短(P＜0.01).与同步对照组相比,悬吊组趾长伸肌的时间参数均未发生改变(P＞0.05).结论由于比目鱼肌最大张力的降低与其萎缩在发生时间上不同步,而等长收缩的时间参数却较早发生改变,提示模拟失重萎缩比目鱼肌中调节性收缩蛋白可能较早发生改变,进而影响收缩性能.     

伏案工作人群职业性颈肩肌肉疼痛运动处方的效果

目的:为有效防治伏案工作人群职业性颈肩肌肉疼痛的发生与发展,制定一套该类人群工作中运动处方并评价其效果。方法:筛选符合入选标准的颈肩肌肉疼痛人员44名,随机分为实验组(n=22人)和对照组(n=22人)。实验组进行运动处方练习:(1)放松:头部旋转,肩带部旋转;(2)牵伸:前外侧肩颈肌牵伸,后外侧肩颈肌牵伸,肩背部牵伸;(3)力量练习:颈前肌肌力训练,颈后及背部肌力训练,肩背部肌力训练,背部肌力训练。每次练习20 min,2次/日,5天/周,共6周。对照组相应时间内暂停工作,适当休息。运动干预前后对两组受试者均进行VAS疼痛评分、颈部关节活动度、上斜方肌最大等长收缩肌力、疲劳检测,所得数据应用t检验进行组内/间分析。结果:6周运动干预后,实验组VAS疼痛评分显著低于对照组(P<0.001);颈椎左右侧屈、左右旋转活动度均显著大于对照组(P<0.05),其他各指标两组无显著性差异。实验组干预前后组内VAS评分显著性降低(P<0.001);左右侧屈关节活动度显著增大(P<0.01);上斜方肌最大收缩肌力显著增大(P<0.01)。对照组运动干预前后各指标均无显著变化(P>0.05)。结论:以颈肩背部肌肉放松、牵伸、等长收缩练习为主的工作中运动处方简便、有效、可行,通过增强颈肩背部关节肌肉功能,能有效改善伏案工作人群颈肩肌肉疼痛症状及颈椎活动情况。     

脊柱软组织诊断治疗仪在颈椎间盘突出症治疗中的应用价值

目的比较脊柱软组织诊断治疗仪加手法治疗与单纯手法治疗颈椎间盘突出症的疗效。方法将56例颈椎间盘突出症随机分为两组:治疗组32例采用手法结合脊柱软组织诊断治疗仪治疗,对照组24例采用单纯手法治疗。结果治疗组总有效率96.6%,明显优于对照组总有效率79.1%(P<0.05)。结论手法结合脊柱软组织诊断治疗仪治疗颈椎间盘突出症能明显缩短病程提高疗效,同时其智能化诊断系统可对临床诊断与判断疗效提供可靠依据。     

女性慢性颈痛患者颈深肌肉形态特征及其与颈肩部姿势相关性研究

目的:观察女性慢性颈痛人群颈椎周围深部肌群的形态特征及其与颈肩部姿势的相关性,为临床开展更有针对性的运动疗法提供依据。方法:按纳入标准共筛选了61名女性受试者,其中38名慢性颈痛患者为颈痛组,无颈痛受试者23名为对照组。采用高频超声成像技术采集卧位两侧头半棘肌和颈深屈肌横截面的前后径和横径作为形态学指标,测量头前伸角度和圆肩角度为颈肩部姿势指标,比较两组间和组内差异,并分别对两组形态学指标和姿势指标进行相关分析。结果:1)头半棘肌组内两侧比前后径和横径之间差异均不显著(P>0.05);组间比较颈痛组左侧横径较对照组大(P<0.05)。颈深屈肌组内两侧比,颈痛组横径之间差异非常显著(P<0.01),对照组前后径之间差异显著(P<0.05);组间比较颈痛组左侧前后径和横径分别小于对照组(P<0.05,P<0.01)。2)颈痛组头前伸角度和圆肩角度两项指标均大于对照组,且差异均非常显著(P<0.01,P<0.01)。3)颈痛组中头前伸角度和圆肩角度之间呈正相关(r=0.434,P<0.05);右侧头半棘肌前后径与头前伸角度呈正相关(r=0.401,P<0.05),左侧颈深屈肌前后径和横径与头前伸角度呈负相关(r=-0.411,P<0.05;r=-0.456,P<0.05)。左侧颈深屈肌的前后径与圆肩角度具有非常显著的负相关性(r=-0.497,P<0.01)。在对照组的相关性分析中,未出现显著相关性。结论:在肌肉形态方面,颈痛组颈深屈肌形态小于对照组,且左右侧差异大;而头半棘肌在形态上大于对照组。在颈肩部姿势方面,颈痛组头前伸和圆肩姿势较对照组更突出。此外,颈深屈肌与颈肩部姿势有较强相关性。在慢性颈痛患者的运动疗法中,应进一步强化颈深屈肌练习。     

非特异性慢性腰背痛飞行员与无症状飞行员之间腰部竖脊肌表面肌电特征比较（摘要）

目的非特异性慢性腰背痛飞行员与无症状飞行员之间腰部竖脊肌表面肌电特征比较,为飞行员非特异性慢性腰背痛患者的客观诊断提供依据。方法用芬兰MEGA公司ME6000一T8表面肌电仪测量43名非特异性慢性腰背痛飞行员与9名无症状飞行员腰部竖脊肌等长收缩与站立位屈伸运动时表面肌电。     

神经肌肉电刺激对前交叉韧带重建术后腘绳肌功能的影响

目的:观察神经肌肉电刺激(NMES)对前交叉韧带(ACL)重建术后腘绳肌功能的影响,为预防自体腘绳肌腱重建ACL术后患侧腘绳肌肌力的下降、及早促进膝关节功能恢复提供依据。方法:选取自体腘绳肌重建ACL男性患者30名为对象,随机分为常规康复组、等长收缩组、神经肌肉电刺激(NMES)组,采用BIODEX等速肌力测试仪测试双侧腘绳肌等长肌力,采用Tensiomyography肌肉状态测试分析仪测试电机械延迟(EMD)和收缩持续时间;行IKDC膝关节主观功能评分。结果:术后3个月患侧腘绳肌等长肌力常规组较术前有所下降,而等长收缩组和NMES组则较术前有所增加,且与常规组均有显著性差异(P<0.05)。半腱肌EMD:术后NMES组较常规康复组和等长收缩组增加较少,均有显著差异性(P<0.05,P<0.01)。股二头肌EMD:术后三组受试对象EMD患侧均较健侧增加,等长收缩组较常规康复组有显著差异性(P<0.05)。半腱肌和股二头肌收缩持续时间:三组患者术前和术后无论是健侧还是患侧股二头肌收缩持续时间均无显著差异性。IKDC评分:三组患者术后3个月与术前差值,常规康复组较等长收缩组差异显著(P<0.05)。结论:术后早期应用NMES可以有效地预防自体腘绳肌腱重建ACL术后腘绳肌肌力的下降以及电机械延迟的延长。     

歼击机飞行员非特异性慢性腰背痛患者腰部竖脊肌表面肌电特征

目的测量分析非特异性慢性腰背痛歼击机飞行员与对照组歼击机飞行员腰部竖脊肌表面肌电（surface electromyography,sEMG）,为歼击机飞行员非特异性慢性腰背痛患者的客观诊断评价提供参考依据。方法芬兰ME6000-T8表面肌电仪测量39名非特异性慢性腰背痛歼击机飞行员（病例组）与12名无症状歼击机飞行员（对照组）腰部竖脊肌俯卧位等长收缩、站立位屈伸运动时的表面肌电。MEGAWIN700046,2．4版软件处理等长收缩时疲劳性肌电信号,获取中位频率下降率（median frequency slope,MFs）、平均功率频率下降率（mean power frequency slope,MPFs）、过零率下降频率（zero crossing rate slope,ZCRs）、平均电压下降率（average electromyography slope,AEMGs）,分析屈伸动作时的肌电信号,得出屈曲伸直动作时的平均肌电电压（averageelectromyography,AEMG）,并由此计算屈曲伸直比（flexion extension ratio,FER）。分析病例组与对照组各指标的差别。结果竖脊肌等长收缩时病例组与对照组疲劳性肌电指标之间无统计学差异。屈伸运动时病例组与对照组AEMG及FER指标有统计学差异（t=1．979～5．387,P％0．05或P％0．01）。结论非特异性慢性腰背痛歼击机飞行员与无症状歼击机飞行员之间的表面肌电指标FER差异显著,屈曲时竖脊肌AEMG增高,伸直时竖脊肌AEMG降低,FER可以作为歼击机飞行员非特异性慢性腰背痛诊断及疗效评价的客观量化参考指标。     

Neck strength and myoelectric fatigue in fighter and helicopter pilots with a history of neck pain

INTRODUCTION: Flight-induced neck pain at high Gz loads or during sustained rotary-wing missions may be caused by limitations in neck muscle function. A better understanding of the contributing factors of excessive external load and internal neck-stabilizing mechanisms would improve the ability to prevent and treat such pain. The aim of this single-blinded cross-sectional study was to evaluate neck neuromuscular function in fighter and helicopter pilots who suffered from frequent neck pain. METHODS: Subjects with pain were 16 fighter pilots (FP-P) and 15 helicopter pilots (HP-P) with frequent neck pain episodes who were compared with pain-free controls (FP-C and HP-C). In all groups, neck extensor and flexor muscles were studied by measuring 1) the strength of maximum voluntary contraction (MVC), and 2) fatigue due to a submaximal isometric contraction. The decline (slope) of the electromyogram (EMG) median frequency power spectra was used as an index of fatigue, while initial median frequency (fi) was taken from the intercept of the regression line. RESULTS: Two-way analysis of variance (ANOVA) revealed interaction effects for extensor MVC. Post hoc testing showed that FP-P had significantly lower extensor MVC (p = 0.03) than FP-C, while there was no such difference for the HP-P vs. HP-C or between the two control groups. There were no significant effects for MVC-balance (flexors/extensors); nor were there any fi or extensor EMG-slope effects. However, there were interaction effects for flexor EMG-slopes: HP-P showed lower slopes than did HP-C (p = 0.02). CONCLUSIONS: To protect and stabilize the head and neck in high Gz environments, higher neck muscle strength is needed; less muscle strength in FP-P may cause further pain and perhaps reduced mission effectiveness. Less localized steep slopes for HP-P might reflect impaired muscle functioning. Specific preventive and clinical attention may be warranted for different types of pilot.     

Sports exercise effect on shortening of saccadic reaction time associated with neck extensor muscle activity

We investigated sports exercise effect on shortening of saccadic reaction time associated with neck extensor muscle activity. Saccadic reaction time was measured in neck rest position, 20 degrees neck flexion, and 30 % muscle contraction of the shoulder girdle elevators for two groups. These groups were an untrained group that has never belonged to any sports club (UT group) and a group that has belonged to high-speed ball sports clubs (HS group). In the neck flexion and 30 % muscle contraction conditions, there was a significant shortening of the reaction time for the HS group. For the UT group, no significant shortening was found in those conditions, and the reaction time in the 30 % contraction was rather significantly longer than that in the rest position. Sports experience pursuing a high-speed ball will be effective in the shortening of the saccadic reaction time associated with the activity of neck extensors.     

Progressive versus rapid rate of contraction during 7 wk of isometric resistance training.

PURPOSE: The aim of this study was to compare the effects of isometric training performed with progressive versus rapid rate of contraction on the knee extensor neuromuscular properties over a 7-wk period. METHODS: Sixteen healthy male subjects trained quadriceps femoris muscle in a leg extension machine three times a week during 7 wk. The training sessions consisted of six sets of six maximal isometric contractions. A first group trained by performing progressive contractions lasting 4 s, whereas a second group performed contractions with a rapid rate of contraction (i.e., ballistic contractions) lasting about 1 s. RESULTS: Both groups significantly increased the isometric and isokinetic voluntary torque, and the respective absolute or relative gains were comparable. Isometric training performed with progressive rate of contraction affected the evoked action potential (M wave) of the vastus lateralis muscle and not the related twitch properties. On the other hand, the isometric training completed with ballistic contractions significantly modified the twitch contractile properties of the knee extensors and not the associated M waves of both vastus medialis and vastus lateralis. CONCLUSION: Knee extensors adapted specifically their neuromuscular properties to the type of rate of contraction performed during 7-wk isometric resistance training. Progressive isometric contractions produced modifications of the nervous system at peripheral level (i.e., muscle membrane electrical activity), whereas ballistic isometric contractions affected the knee extensor contractile muscle properties (i.e., excitation-contraction coupling).     

Cardiovascular responses to isometric neck muscle contractions: results after dynamic exercise with various headgear loading configurations

Experiments were conducted to quantify the cardiovascular response (blood pressure and heart rate) elicited by sustained isometric contractions of the neck muscles. The response was secondary to dynamic exercise with various headgear loading combinations. The neck muscles were loaded by the head itself (CON), the standard U.S. Army SPH-4 helmet (HEL), and a combination of the SPH-4 helmet with Night Vision Goggles (H/NVG). During two exercise periods of 5 min and 35 min, each of the five subjects would rotate the head from side-to-side in the CON, HEL, or H/NVG configuration. Immediately thereafter, the subject would position his head in an isometric head dynamometer and exert a sustained right lateral (LAT) neck contraction or forward (FOR) neck contraction at 70% of a maximal voluntary contraction (MVC). During this isometric neck muscle contraction, the subject's endurance time to fatigue was recorded, the blood pressure was manually recorded, and the heart rate was continuously recorded. Characteristic increases in the systolic and diastolic blood pressure and heart rate occurred with sustained isometric neck muscle contractions. There was an average 40% increase in the systolic blood pressure, an average 50% increase in the diastolic blood pressure, and an average 45% increase in the heart rate from resting to the end of a fatiguing 70% MVC (p less than 0.05). These responses appear to be relatively independent of the duration of the exercise period, the loading during the exercise period, and the specific muscle mass involved. The mechanisms for the pressor response and the heart rate response are reviewed.     

Fast unilateral isometric knee extension torque development and bilateral jump height

PURPOSE: We hypothesized that the initial rate (first 40 ms) of unilateral knee extensor torque development during a maximally fast isometric contraction would depend on the subjects' ability for fast neural activation and that it would predict bilateral jumping performance. METHODS: Nine males (21.8 +/- 0.9 yr, means +/- SD) performed unilateral fast isometric knee extensions (120 degrees knee angle) without countermovement on a dynamometer and bilateral squat jumps (SJ) and countermovement jumps (CMJ) starting from 90 and 120 degrees knee angles (full extension = 180 degrees ). The dynamometer contractions started either from full relaxation or from an isometric pre-tension (15% maximal isometric torque, Tmax). Torque time integral for the first 40 ms after torque onset (TTI-40, normalized to Tmax) and averaged normalized rectified knee extensor EMG for 40 ms before fast torque onset (EMG-40) were used to quantify initial torque rise and voluntary muscle activation. RESULTS: TTI-40 without pre-tension (range: 0.02-0.19% Tmax per second) was significantly lower than TTI-40 with pre-tension, and both were significantly (r = 0.81 and 0.80) related to EMG-40. During jumping, similar significant positive relations were found between jump height and knee extensor EMG during the first 100 ms of the rise in ground reaction force. There also were significant positive linear relations between dynamometer TTI-40 and jump height (r = 0.75 (SJ 90), 0.84 (SJ 120), 0.76 (CMJ 90), and 0.86 (CMJ 120)) but not between dynamometer Tmax and jump height (-0.16 < r < 0.02). CONCLUSION: One-legged TTI-40 to a large extent explained the variation in jump height. The ability to produce a high efferent neural drive before muscle contraction seemed to dominate performance in both the simple single-joint isometric task and the complex multijoint dynamic task.     

The effects of 12 weeks of functional strength training on muscle strength,volume and activity upon exposure to elevated Gz forces in high-performance aircraft personnel

Background:Technological advancements in modern military and acrobatic jet planes have resulted in extraordinary psychophysiological loads being exerted upon flying personnel,including inducing neck and back pain.The purpose of this study was to examine the effects of 12 weeks of functional strength training on 1) the volume and strength of the neck and shoulder muscles and 2) muscular activity upon exposure to helmets of different masses and elevated Gz forces in a long-arm centrifuge in high-performance aircraft personnel.Methods:Eighteen participants underwent 12 weeks of functional strength training (n=12) or the control protocol(n=6) without additional strength training.Pre-and post-intervention tests included evaluations of isometric strength of the head extensor muscles,flexion,and lateral flexion and rotation,as well as magnetic resonance imaging (MRI)to measure the volume of the m.stemocleidomastoideus,m.trapezius,and deep neck muscles.Furthermore,during a long-arm centrifuge (+1.4 and +3Gz) protocol,the muscular activity levels of the m.sternocleidomastoideus,m.trapezius and m.erector spinae muscles were assessed without a flight helmet,with a helmet,and with a helmet and night vision goggles.Each participant's perception of muscular strain was noted immediately after the long-arm centrifuge protocol.Results:The maximal isometric strength in all exercises and muscle volumes increased in the training group but not the control group (P＜0.05).Relative muscle activity (％MVC) with a helmet decreased after the intervention in the training but not the control group (P=0.01).Relative muscle activity while wearing a helmet and night vision goggles was higher after intervention in the control group than in the training group (P＜0.01).The perceived muscular strain of the neck muscles induced by the long-arm centrifuge did not differ between the groups.Conclusions:Twelve weeks of functional strength training improves the maximal isometric strength and volume of neck and shoulder muscles and leads to lower relative muscle activation upon exposure to elevated Gz forces in a long-arm centrifuge.     

Effects of prior exercise on the performance of intense isometric exercise.

The influence of a regimen designed to lower the muscle glycogen content on the capacity to perform a single brief isometric contraction has been studied. Eight male subjects performed a single exhausting isometric contraction of the knee extensor muscles at a tension corresponding to 60% of maximum voluntary contraction (MVC). This was followed by prolonged cycling exercise at a work rate equivalent to approximately 75% of maximum oxygen uptake in order to reduce the muscle glycogen content. A diet low in carbohydrate was consumed for the remainder of this day in order to retard the resynthesis of muscle glycogen. The isometric contraction at 60% of MVC was repeated on the following day. Endurance time on the first day was 53.8 +/- 8.4 s (mean +/- SD); this was reduced (45.8 +/- 12.1 s; p less than 0.02) on the second day. From previously published data on rates of muscle glycogen utilisation during isometric exercise, it seems probable that insufficient glycogen is available in the muscle under the low carbohydrate condition to enable maximum performance to be achieved.     

Shared genetic and environmental effects on strength and power in older female twins

PURPOSE: This study examined the relative contribution of genetic and environmental effects on maximal leg extensor power and also investigated whether leg extensor power and maximum voluntary isometric knee extensor strength share a genetic component. METHODS: Muscle functions were measured as part of the Finnish Twin Study on Aging in 101 monozygotic (MZ) and 116 dizygotic (DZ) female twin pairs aged 63-76 yr. Leg extensor power was measured using the Nottingham Leg Extensor Power Rig and maximum voluntary isometric knee extensor strength using an adjustable dynamometer chair. The analyses were carried out using the maximum likelihood method in Mx-program on the raw data set. RESULTS: A bivariate Cholesky decomposition model showed that leg extensor power and isometric knee extensor strength shared a genetic component in common, which accounted for 32% of the total variance in leg extensor power and 48% in isometric knee extensor strength. In addition, power and strength had a nonshared environmental effect in common accounting for four percent of the variance in power and 52% in strength. Remaining variance for leg extensor power was due to trait-specific shared and nonshared environmental effects. CONCLUSION: Observed genetic effect in common for leg extensor power and maximum voluntary isometric knee extensor strength indicated that these two traits are regulated by the same genes. However, also environmental effects have a significant role in explaining the variability in power and strength.