基于蓝牙通信的等长肌力测试仪的设计

设计一种集肌力测试与评定于一体的等长肌力测试仪.采用无线蓝牙通信技术,手持式肌力测试装置与上位机之间可在10 m距离范围内进行无线通信,将肌力相关的数据进行传输,由上位机对肌肉功能障碍患者不同部位的等长肌力、肌张力、峰力矩等参数进行定量检测与分析.软件采用统一的建模语言(UML),使用VC++应用软件编程,并通过开放数据库互连(ODBC)的方式,实现肌力、肌电数据同步采集和处理.对20名正常人进行初步测试,各参数的组内相关系数(ICC)均大于0.6.该仪器具有操作简便,实用性强等特点,可为临床制定康复计划和评价康复疗效提供客观的数据.     

等长收缩时食指肌力分析

本文详尽深入地探讨了在等长收缩时食指肌力冗余问题的求解方法。分别采用二维和三维肌骨模型选用７ 类２１ 种优化目标函数,求得食指在进行按压动作时的肌肉作用力;在此基础上,分析了不同模型和不同的优化目标函数对肌力解的影响,得到了一些很有意义的结论,如：三维模型中不同目标函数的选择对肌力解的影响比在二维模型中小,浅层屈肌和深层屈肌作用力的之和基本不随优化目标函数的不同而改变,而蚓状肌和骨间肌的力解对优化目标函数的选择却很敏感     

微机控制大鼠肌力测试模型及意义

肌力测试是医学生物力学实验的常用手段。以往由于设备技术所限，测试值数据采集不便。我们采用微机控制建立该测试模型，在技术手段上更进了一步。并且数据采集也更为精确方便。１材料和方法１１实验动物 实验动物由第一军医大学实验动物中心提供。正常成年雄性ＳＤ大鼠２４只，体重２４０～２６０ｇ。１．２设备 丹麦产Ｄａｎｔｅｃ牌Ｍ２０００型神经肌电图仪；力学试验微机控制及数据采集系统（Ｔｗａｙ），微机软件程序由本研究室与本校医工系合作开发；上海产显微手术器机及头戴式手术放大镜。１．３模型制作 实验准备：２％戊巴比妥…     

等速肌力测试技术在髋关节运动及创伤评估中的应用

目的探讨等速肌力测试技术在髋关节运动及创伤评估中的应用现状。方法在PubMed、万方等数据库上以“髋关节”、“生物力学”、“肌力”、及“等速测试”为关键词检索1990年1月—2014年5月国内外有关等速肌力测试技术在髋关节运动及损伤评估中应用的相关文献,进行分析总结。结果等速肌力测试技术作为一种动态肌力测试技术,不仅能够对运动员髋关节的肌肉功能进行定量测试,指导运动员进行专项训练;同时,能够为髋关节创伤后的功能情况提供客观评价指标,对设计合理的、有针对性的康复训练方案有指导意义。采用等速肌力测试技术可对髋关节运动创伤的发生进行相关性研究,有望探索一套预防运动创伤发生的基本方法。结论等速肌力测试技术对髋关节运动及创伤的评估、治疗及预防有重要意义。     

87例慢性阻塞性肺疾病患者上下肢肌力等速测试分析

目的　运用等速肌力测试分析慢性阻塞性肺疾病（COPD）患者上、下肢屈、伸肌群的肌力情况。 方法　对87例COPD患者（实验组,其中轻度17例、中度44例、重度26例）和34例健康体检者（对照组）进行肘和膝屈、伸肌群等速肌力测试,分别记录角速度60°/s、180°/s时上、下肢屈、伸肌群的峰力距;计算下肢屈、伸肌群的易疲劳指数。 结果　实验组屈肘肌群和伸肘肌群峰力距分别为（20.56±7.54）N·m、（22.61±9.26）N·m,屈膝肌群和伸膝肌群峰力距分别为（35.78±16.99）N·m、（71.86±27.98）N·m,均低于对照组（P＜0.05）;实验组下肢屈、伸肌群的易疲劳指数低于对照组（P<0.05）。 结论　等速肌力测试可作为分析COPD患者外周肌力变化的一种方法。     

87例慢性阻塞性肺疾病患者上下肢肌力等速测试分析

目的　运用等速肌力测试分析慢性阻塞性肺疾病（COPD）患者上、下肢屈、伸肌群的肌力情况。 方法　对87例COPD患者（实验组,其中轻度17例、中度44例、重度26例）和34例健康体检者（对照组）进行肘和膝屈、伸肌群等速肌力测试,分别记录角速度60°/s、180°/s时上、下肢屈、伸肌群的峰力距;计算下肢屈、伸肌群的易疲劳指数。 结果　实验组屈肘肌群和伸肘肌群峰力距分别为（20.56±7.54）N·m、（22.61±9.26）N·m,屈膝肌群和伸膝肌群峰力距分别为（35.78±16.99）N·m、（71.86±27.98）N·m,均低于对照组（P＜0.05）;实验组下肢屈、伸肌群的易疲劳指数低于对照组（P<0.05）。 结论　等速肌力测试可作为分析COPD患者外周肌力变化的一种方法。     

自动肌力训练仪在脑瘫康复中的应用

目的观察自动肌力训练仪配合功能训练对提高脑瘫患儿肌力的治疗效果。方法50例脑瘫患儿分为治疗组30例,对照组20例。所有病人都进行常规康复训练,治疗组在此基础上加用自动肌力训练仪进行训练,每天1-2次,每次20-40min,2-3个月为1个疗程。治疗前后都进行运动功能评定（采用GMFM粗大运动功能评定量表）。结果对照组和治疗组GMFM评定站立项和走、攀登项评分比治疗前明显提高,但治疗组提高更显著（P〈0.05）。结论自动肌力训练仪训练能有效提高脑瘫患儿运动功能,可作为重要的肌力训练辅助手段。     

青少年运动员肩关节屈伸肌等速肌力测试与分析

BACKGROUND: The isokinetic muscle strength test system can quantitatively test the shoulder flexor and extensor muscles and objectively analyze the relationship between size and balance of flexor and extensor. Therefore, it could be used for strength training monitoring as well as prediction and rehabilitation of sports injuries. OBJECTIVE: To understand shoulder flexor and extensor strength characteristics of adolescent softball players, and find out shortcomings in the shoulder flexor and extensor strength to provide guidance for adolescent athletes’ strength training and point out possible sports injury risks caused by imbalanced strength. METHODS: ISOMED2000 isokinetic testing system (D&R, Germany) was employed to test the isokinetic strength of shoulder flexor and extensor of 12 adolescent female softball players from Shanghai Sports University, China. RESULTS AND CONCLUSION: With the increase of test speed, the bilateral shoulder flexor and extensor peak torque, the flexor and extensor average power ratio, and the flexor and extensor powers were reduced, but the flexor and extensor average power was on the rise. Under the same test speed, flexor and extensor peak torque, the flexor and extensor peak torque ratio, the flexor and extensor average power, the flexor and extensor average power ratio and the flexor powers of the throwing shoulder were significantly larger than those of the non-throwing shoulder (P < 0.05), while the extensor peak torque and the extensor average power of the throwing and non-throwing shoulders showed no significant differences (P > 0.05). Under the same test speed, bilateral shoulder homonymous flexor strength ratio was larger than that of the extensor, and the extensor power of the throwing shoulder was less than that of the non-throwing shoulder. The ratio of homolateral shoulder flexor and extensor ranged from 70% to 80%. These results indicate that there is a significant difference between the flexor strength of the bilateral shoulders in adolescent softball players, but the bilateral extensor strength is similar. Flexor fast strength and extensor maximum strength of the throwing shoulder are lower. Besides, the isokinetic muscle strength test system can be used to evaluate the flexor and extensor strength in adolescent softball athletes, based on which coaches can give targeted strength training in adolescent softball athletes. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

股四头肌作等长收缩时的粘弹性分析

本文用一个粘弹性流变学模型来模拟股四头肌作等长收缩时的松驰过程。在求解非线性松弛函数时，采用了蒙特卡洛，最速下降，牛顿，马柯尔特和共轭梯度法等最优化方法。其结果表明所设的粘弹性模型很好地模拟了股四头肌作等长收缩的松驰过程。两位测试者的Ｅ１和μ比较接近，而对于Ｅ２，运动员约是普通人的２倍。说明运动训练对Ｅ２有显著的影响。在本文优化计算过程中，蒙特卡洛方法是一种有效的方法，其它几种方法由于指数项的存在和因初始参数的不恰当而常常发散。     

The isometric force that induces maximal surface muscle deoxygenation

To determine the external force that induces maximal deoxygenation of brachioradialis muscle 32 trained male subjects maintained isometric contractions using the elbow flexor muscles up to the limit time (isotonic part of the isometric contraction, IIC) and beyond that time for 120 s (anisotonic part of the isometric contraction). During IIC each subject maintained relative forces of either 25% and 70% maximal voluntary contraction (MVC), 50% and 100% MVC, or 40% and 60% MVC. Muscle oxygenation was assessed using a near infrared spectroscope, and expressed as a percentage of the reference value (ΔO_2rest) which was the difference between the minimal oxygenation obtained after 6 min of ischaemia at rest and the maximal reoxygenation following the release of the tourniquet. During IIC at 25% MVC, muscle oxygenation decreased to 17 (SEM 3)% ΔO_2rest, then it levelled off [25 (SEM 1)% ΔO_2rest]. After the point at which target force could not be maintained, reoxygenation was very weak. During IIC at 40%, 50%, 60%, and 70% MVC, the lowest muscle oxygenation values were obtained after 15–20 s of contraction and corresponded to ?18 (SEM 6), ?59 (SEM 12) ?31 (SEM 6), and ?29 (SEM 6)% ΔO_2rest, respectively. For the contraction at 100% MVC, the lowest oxygenation [?19 (SEM 9)% ΔO_2rest] was obtained while force was decreasing (69% MVC). During the anisotonic part of the isometric contractions, the greatest reoxygenation rate was obtained after 50% MVC IIC (P?相似文献   

Gradual potentiation of isometric muscle force during constant electrical stimulation

An investigation was carried out into how stimulation frequency and stimulation history affect the potentiation of muscle force during 20s of constant stimulation of the two knee extensors in isometric conditions. Stimulation frequency significantly affected the potentiation pattern: low-frequency (2.5–10 Hz) stimulation showed a reduction and subsequent enhancement of force, and high-frequency (14.3–25 Hz) stimulation showed only enhancement of force. The degree of enhancement in force and time-to-peak decreased with the stimulation frequency. Whereas conditioning stimulation (both 40 Hz and 14.3 Hz) significantly enhanced the muscle force above 85%, following main stimulation (14.3 Hz) after short rest (10 s and 50 s, respectively) induced little force enhancement (below 8%). In particular, when the frequency of the conditioning stimulation was 14.3 Hz, the initial force at the main stimulation showed a very similar value to the final force value of the conditioning stimulation (above 90% similarity). The potentiated twitch force slowly decayed during rest, with an average time constant of 2.4 min. These observations indicate that muscle potentiation depends on the stimulation frequency and stimulation history, and therefore a computer model of potentiation can play an important role in predicting muscle force and body movement induced by electrical stimulation.     

Biomimetic model of skeletal muscle isometric contraction: I. an energetic-viscoelastic model for the skeletal muscle isometric force twitch

This paper describes a revision of the Hill-type muscle model so that it will describe the chemo-mechanical energy conversion process (energetic) and the internal-element stiffness variation (viscoelastic) during a skeletal muscle isometric force twitch contraction. The derivation of this energetic-viscoelastic model is described by a first-order linear ordinary differential equation with constant energetic and viscoelastic coefficients. The model has been implemented as part of a biomimetic model, which describes the excitation-contraction coupling necessary to drive the energetic-viscoelastic model. Finally, the energetic-viscoelastic model is validated by comparing its isometric force-time profile with that of various muscles reported in the literature.     

Mechanisms underlying the reduction of isometric force in skeletal muscle fatigue

A decline of isometric force production is one characteristic of skeletal muscle fatigue. In fatigue produced by repeated short tetani, this force decline can be divided into two components: a reduction of the cross-bridges' ability to generate force, which comes early; and a reduction of the sarcoplasmic reticulum Ca²⁺ release, which develops late in fatigue. Acidification due to lactic acid accumulation has been considered as an important cause of the reduced cross-bridge force production. However, in mammalian muscle it has been shown that acidification has little effect on isometric force production at physiological temperatures. By exclusion, in mammalian muscle fatigue, the reduction of force due to impaired cross-bridge function would be caused by accumulation of inorganic phosphate ions, which results from phosphocreatine breakdown. The reduction of sarcoplasmic reticulum Ca²⁺ release in late fatigue correlates with a decline of ATP and we speculate that the reduced Ca²⁺ release is caused by a local increase of the ADP/ATP ratio in the triads.     

Estimation of elbow flexion force during isometric muscle contraction from mechanomyography and electromyography

Mechanomyography (MMG) is the muscle surface oscillations that are generated by the dimensional change of the contracting muscle fibers. Because MMG reflects the number of recruited motor units and their firing rates, just as electromyography (EMG) is influenced by these two factors, it can be used to estimate the force exerted by skeletal muscles. The aim of this study was to demonstrate the feasibility of MMG for estimating the elbow flexion force at the wrist under an isometric contraction by using an artificial neural network in comparison with EMG. We performed experiments with five subjects, and the force at the wrist and the MMG from the contributing muscles were recorded. It was found that MMG could be utilized to accurately estimate the isometric elbow flexion force based on the values of the normalized root mean square error (NRMSE = 0.131 ± 0.018) and the cross-correlation coefficient (CORR = 0.892 ± 0.033). Although MMG can be influenced by the physical milieu/morphology of the muscle and EMG performed better than MMG, these experimental results suggest that MMG has the potential to estimate muscle forces. These experimental results also demonstrated that MMG in combination with EMG resulted in better performance estimation in comparison with EMG or MMG alone, indicating that a combination of MMG and EMG signals could be used to provide complimentary information on muscle contraction.     

Changes in isometric force of mouse soleus muscle during the oestrous cycle

 Muscles excised from young female mice at known phases of the oestrous cycle were studied in vitro to determine if there are variations in force analogous to those that occur in vivo during the menstrual cycle in women. Oestrous phase was determined from vaginal smears. The maximum isometric and eccentric forces of pairs of isolated soleus muscles were measured. The first muscle was studied immediately after dissection, the second after incubation in Ringer solution for up to 2 h. Normalised isometric muscle force in the first muscle of each pair depended on the oestrous phase, the force being greatest during dioestrus. There was a negative correlation between normalised force and the eccentric/isometric force ratio. Neither of these phenomena was found with the second muscle of each pair. These results show that in mouse soleus muscle cross-bridge function does vary according to the phase of the oestrous cycle. However, the rise in force does not follow the pattern of the rise in blood oestrogen levels as it does in humans, and in the mouse the effect on cross-bridge function washes out after a few hours in vitro. Received: 7 October 1997 / Received after revision: 20 April 1998 / Accepted: 3 September 1998     

Error associated with antagonist muscle activity in isometric knee strength testing

The purpose of this study was to determine the measurement error associated with antagonist muscle activity in isometric knee strength testing at 60° of knee flexion in both sexes. Muscle specific EMG–contraction intensity relationships were obtained from 22 young people by having them match moment targets ranging from 10% to 100% peak moment. The moments attributed to each of the quadriceps and hamstrings muscles were partitioned using a practical mathematical model. Subject specific EMG–moment relationships were defined for each muscle using second-order polynomial equations. These equations were subsequently used to predict the countermoment associated with antagonist muscle activity. Error during strength testing was calculated by expressing net antagonist moments as a percentage of net agonist moments. The net antagonist moments associated with quadriceps and hamstrings muscle activity were 11.0% and 8.7% of the peak moment values recorded when the same muscle groups were acting as agonists. The error associated with antagonist activity was significantly higher in knee flexion (20.1%) than in knee extension (4.5%). Females displayed significantly higher error in knee flexor testing (P < 0.001). Limb symmetry indices did not change significantly when the countermoments generated by the antagonist muscles were accounted for (P > 0.05). The results of this study indicate that the error associated with antagonist activity in knee extensor testing is relatively small, whereas the error in knee flexor testing is larger. This is due to the quadriceps being much stronger than the hamstrings muscles while displaying similar levels of antagonist activity.     

Mechanomyogram and force relationship during voluntary isometric ramp contractions of the biceps brachii muscle

The aim of the present study was to examine the non-stationary mechanomyogram (MMG) during voluntary isometric ramp contractions of the biceps brachii muscles using the short-time Fourier transform, and to obtain more detailed information on the motor unit (MU) activation strategy underlying in the continuous MMG/force relationship. The subjects were asked to exert ramp contractions from 5% to 80% of the maximal voluntary contraction (MVC) at a constant rate of 10% MVC/s. The root mean squared (RMS) amplitude of the MMG began to increase slowly at low levels of force, then there was a slight reduction between 12% and 20% MVC. After that, a progressive increase was followed by a decrease beyond 60% MVC. As to the mean power frequency (MPF), a relatively rapid increase up to 30% MVC was followed by a period of slow increment between 30% and 50% MVC. Then temporary reduction at around 50% MVC and a further rapid increase above 60% MVC was observed. The interaction between amplitude and MPF of the MMG in relation to the MU activation strategy is discussed for five force regions defined on the basis of their inflection points in the RMS-amplitude/force and MPF/force relationships. It was found that the MMG during ramp contractions enables deeper insights into the MU activation strategy than those determined during traditional separate contractions. In addition, this contraction protocol is useful not only to ensure higher force resolution in the MMG/force relationship, but also to markedly shorten the time taken for data acquisition and to reduce the risk of fatigue. Accepted: 31 August 2000     

Actomyosin energy turnover declines while force remains constant during isometric muscle contraction

Energy turnover was measured during isometric contractions of intact and Triton-permeabilized white fibres from dogfish ( Scyliorhinus canicula ) at 12°C. Heat + work from actomyosin in intact fibres was determined from the dependence of heat + work output on filament overlap. Inorganic phosphate (P_i) release by permeabilized fibres was recorded using the fluorescent protein MDCC-PBP, N-(2-[1-maleimidyl]ethyl)-7-diethylamino-coumarin-3 carboxamide phosphate binding protein. The steady-state ADP release rate was measured using a linked enzyme assay. The rates decreased five-fold during contraction in both intact and permeabilized fibres. In intact fibres the rate of heat + work output by actomyosin decreased from 134 ± s.e.m. 28 μW mg⁻¹ ( n = 17) at 0.055 s to 42% of this value at 0.25 s, and to 20% at 3.5 s. The force remained constant between 0.25 and 3.5 s. Similarly in permeabilized fibres the P_i release rate decreased from 5.00 ± 0.39 mmol l⁻¹ s⁻¹ at 0.055 s to 39% of this value at 0.25 s and to 19% at 0.5 s. The steady-state ADP release rate at 15 s was 21% of the P_i rate at 0.055 s. Using a single set of rate constants, the time courses of force, heat + work and P_i release were described by an actomyosin model that took account of the transition from the initial state (rest or rigor) to the contracting state, shortening and the consequent work against series elasticity, and reaction heats. The model suggests that increasing P_i concentration slows the cycle in intact fibres, and that changes in ATP and ADP slow the cycle in permeabilized fibres.