等长收缩运动治疗单纯颈伸肌劳损的疗效观察

目的总结等长收缩运动治疗单纯颈伸肌劳损的疗效。方法随机将56例单纯颈伸肌劳损分为两组,一组应用等长收缩运动进行治疗,另一组应用手法治疗,对比两组患者疗效。结果治疗1周后,两组患者的总有效率均为100%（P〉0.05）。结论等长收缩运动治疗单纯颈伸肌劳损的疗效与手法治疗相近,但该法具有更安全、经济、且不受条件、时间限制,更有主动巩固疗效和积极预防的作用。     

等距和非等距前交叉韧带重建的对比实验

目的 观察等距和非等距前交叉韧带(anterior cruciate ligament，ACL)重建对膝关节功能的影响。方法 采用新鲜尸体观察等距ACL的解剖结构，在尸体和模型上重建等距和非等距ACL，分别观察重建后ACL长度和胫骨平台表面压强的变化。结果 等距ACL的重建在膝关节的全范围活动中长度的变化值最小，胫骨平台所受的压强也最小。结论 只有等距的ACI。的重建才能恢复膝关节的正常生理功能，而非等距重建的ACL会造成膝关节的不稳定(或活动受限)，或者使膝关节表面的压强增加。     

EMG power spectra of elbow extensors during ramp and step isometric contractions

Summary The goal of the present study was to compare electromyogram (EMG) power spectra obtained from step (constant force level) and ramp (progressive increase in the force level) isometric contractions. Data windows of different durations were also analysed for the step contractions, in order to evaluate the stability of EMG power spectrum statistics. Fourteen normal subjects performed (1) five ramp elbow extensions ranging from 0 to 100% of the maximum voluntary contraction (MVC) and (2) three stepwise elbow extensions maintained at five different levels of MVC. Spectral analysis of surface EMG signals obtained from triceps brachii and anconeus was performed. The mean power frequency (MPF) and the median frequency (MF) of each power spectrum were obtained from 256-ms windows taken at 10, 20, 40, 60 and 80% MVC for each type of contraction and in addition on 512-, 1024-and 2048-ms windows for the step contractions. No significant differences (P>0.05) were found in the values of both spectral statistics between the different window lengths. Even though no significant differences (P>0.05) were found between the ramp and the step contractions, significant interactions (P<0.05) between these two types of contraction and the force level were found for both the MPF and the MF data. These interactions point out the existence of different behaviours for both the MPF and the MF across force levels between the two types of contraction.     

Use of the iso-inertial force mass relationship in the prediction of dynamic human performance

The purpose of this investigation was to develop a new test of muscle function, termed the isoinertial force-mass relationship, and to determine its relationship to dynamic physical performance in comparison to an isometric test. A group of 13 trained subjects performed an isometric, and a series of iso-inertial maximal upper body tests, in a bench press movement at loads of 30%, 60%, 100% (concentric) and 100%, 130% and 150% (eccentric) of maximum. Vertical forces exerted throughout the movement were recorded by a force plate. In addition, the subjects performed the following three performance tests: a maximal bench press, a seated shotput, and two drop bench-press throws from a height of 0.25 m, with loads of 10 kg and 30% of maximum. Correlation analysis demonstrated that in each instance the iso-inertial force mass tests were the best predictors of performance (r=0.78–0.88) with both contraction type and mass specific effects apparent. Maximal isometric force and rate of force development were significantly related to some performance variables (r=0.22–0.78). However, for all the performance movements assessed, the iso-inertial test modality recorded the highest relationship to performance. The difference in the relationship between performance and iso-inertial and isometric test modalities was particularly evident in the light load dynamic performance of the seated shotput (r=0.86 vsr=0.38, respectively). These results are explained in part by the neural and mechanical differences between iso-inertial and isometric muscle actions and their respective specificity to dynamic physical performance.     

Human motor compensations for thixotropy‐dependent changes in muscular resting tension after moderate joint movements

Aim: This study on healthy subjects explores history‐dependent changes in the resting tension of relaxed wrist muscles after moderate joint excursions and the motor control consequences of these changes during voluntary wrist joint position maintenance. Methods: Integrated surface electromyogram (IEMG) was recorded from wrist extensor/flexor muscles. Angular position and torque were recorded from the wrist joint. Changes in wrist flexor muscle resting tension were sensed by a force transducer pressed against the tendons. Results: Consecutive stepwise changes (7.5°) in wrist joint position (within the dorsiflexed range) were either imposed on relaxed subjects or actively performed while the subjects under visual guidance tried to mimic the passive movements. In relaxed subjects, passive joint torque resistance at a given steady dorsiflexed position either gradually declined or rose depending on the direction of the previous transition movements. In corresponding voluntary contraction experiments, the IEMG amplitude from position holding wrist extensors was found to vary in a similar way as the passive torque resistance. Further, there was a strong correlation between history‐dependent changes in extensor IEMG amplitude and stress alterations exhibited by the relaxed antagonist flexors. The above described, slowly subsiding post‐movement mechanical and motor adaptations were accelerated by brief forceful cocontractions of the forearm muscles. Conclusion: Moderate stepwise changes in joint position are sufficient to induce history‐dependent after‐effects in passive muscular resting tension, after‐effects which during voluntary position holding are effectively compensated for by the motor control system.     

等长收缩运动中血浆内啡呔的检测及评价

目的观察健康青年人在等长收缩运动(IE)时血浆内啡肽(EOPs)的变化.方法选择健康自愿受试者40例,男女各20例,平均年龄(23.7±2.9)岁,研究设置二种模型即主观运动和被动运动.观察指标包括血浆中的亮氨酸脑啡肽(LEK)、β-内啡呔(β-END)和强啡呔(DYN).结果LEK、β-END、DYN在IE中均有不同程度的变化.结论在IE中LEK、DYN的变化程度较β-END明显(P＜0.01).     

NIOSH提举指数在下背痛流行病学研究中的应用

[目的 ]探讨美国国家职业安全卫生研究所提出的手工作业提举指数 (LI)与下背痛患病率的关系。[方法 ]在 3个具有典型提举作业的工厂中采用流行病学横断面调查方法 ,利用NIOSH提出的提举指数进行接触负荷评价 ,按照Nordic肌肉骨骼症状分析调查表对 491名从事手工提举作业的工人和 3 4名无明显提举任务的行政人员进行问卷调查 ,并对静态肌力进行测试。根据提举指数分为 0 ,～ 1,～ 2 ,～ 3 ,>3共 5组。观察各组工人不同部位肌肉骨骼疾患的患病情况 ,并分析提举指数与下背痛患病的关系。 [结果 ]在肌肉骨骼症状中 ,下背痛的发生率最高。当LI增高时 ,下背痛的OR值也随之增加 ,但其峰值出现在～ 3组 (OR =1.3 5 ) ,而LI >3 ,其OR值并非最高 ,仅为 1.3 0。平均腰拉力最大的为～ 1组 ( 95 .5 9± 2 1.76)kg ,而对照组和LI >3组则分别为 ( 80 .3 6± 14 .49)kg、( 86.85± 2 0 .3 3 )kg。 [结论 ]提举指数对手工提举所引起的下背痛是一个有意义的危险度评价指标。过度手工提举活动可能降低腰拉力。     

Key changes in denervated muscles and their impact on regeneration and reinnervation

The neuromuscular junction becomes progressively less receptive to regenerating axons if nerve repair is delayed for a long period of time. It is difficult to ascertain the denervated muscle＇s residual receptivity by time alone. Other sensitive markers that closely correlate with the extent of denervation should be found. After a denervated muscle develops a fibrillation potential, muscle fiber conduction velocity, muscle fiber diameter, muscle wet weight, and maximal isometric force all decrease; remodeling increases neuromuscular junction fragmentation and plantar area, and expression of myogenesis-related genes is initially up-regulated and then down-regulated. All these changes correlate with both the time course and degree of denervation. The nature and time course of these denervation changes in muscle are reviewed from the literature to explore their roles in assessing both the degree of detrimental changes and the potential success of a nerve repair. Fibrillation potential amplitude, muscle fiber conduction velocity, muscle fiber diameter, mRNA expression levels of myogenic regulatory factors and nicotinic acetylcholine receptor could all reflect the severity and length of denervation and the receptiveness of denervated muscle to regenerating axons, which could possibly offer an important clue for surgical choices and predict the outcomes of delayed nerve repair.     

Development,validity and reliability of a new pressure air biofeedback device (PAB) for measuring isometric extension strength of the lumbar spine

This study describes the development of a new portable muscle testing device, using air pressure as a biofeedback and strength testing tool. For this purpose, a pressure air biofeedback device (PAB^®) was developed to measure and record the isometric extension strength of the lumbar multifidus muscle in asymptomatic and low back pain (LBP) persons. A total of 42 subjects (age 47.58 years, ±18.58) participated in this study. The validity of PAB^® was assessed by comparing a selected measure, air pressure force in millibar (mb), to a standard criterion; calibrated weights in kilograms (kg) during day-to-day tests. Furthermore, clinical trial-to-trial and day-to-day tests of maximum voluntary isometric contraction (MVIC) of L5 lumbar multifidus were done to compare air pressure force (mb) to electromyography (EMG) in microvolt (μV) and to measure the reliability of PAB^®. A highly significant relationship were found between air pressure output (mb) and calibrated weights (kg). In addition, Pearson correlation calculations showed a significant relationship between PAB^® force (mb) and EMG activity (μV) for all subjects (n?=?42) examined, as well as for the asymptomatic group (n?=?24). No relationship was detected for the LBP group (n?=?18). In terms of lumbar extension strength, we found that asymptomatic subjects were significantly stronger than LBP subjects. The results of the PAB^® test differentiated between LBP and asymptomatic subject’s lumbar isometric extension strength without any risk to the subjects and also indicate that the lumbar isometric extension test with the new PAB^® device is reliable and valid.