高频程控增益前置放大器的设计及其在医学仪器中的应用

目的：设计一种高频程控增益前置放大器，以满足“便携式数字型医用超声声功率计”研究的需要。方法：根据医用超声源频率范围宽、输出功率相差悬殊的特点，权衡便携、低功耗与低失真度、价格等因素，针对不同应用条件，制作出分别由集成电路和分立元件构成的两种结构不同的高频程控增益前置放大器，经调试、优化后，应用到医用超声声功率计中。结果：两种电路分别应用于“便携式数字型医用超声声功率计”，经试用，效果良好。结论：实践证明，由集成电路组成的放大器具有体积小、功耗低、电路结构简单、易与微处理器接口等优点，但它对器件依赖性强，信号保真度差，价格昂贵；而分立元件组成的放大器虽然体积、功耗、与微处理器接口等方面逊于前者，但它元器件易得，信号保真度好，价格低廉。在体积、功耗等条件许可的情况下，该放大器不失为上乘选择。     

高频宽增益小信号放大器的设计及在医用超声功率计中的应用

介绍供医用超声功率计用的两种高频、宽增益的小信号放大器，并比较了它们彼此的优缺点。     

Isokinetic quadriceps training in patients with patellofemoral pain syndrome

The aims of the present investigation were (a) to evaluate the effect of eccentric quadriceps training in patients with unilateral patellofemoral pain and (b) to compare the effect of eccentric and concentric quadriceps training in patients with bilateral patellofemoral pain. Fifteen patients (9 male and 6 female, aged 17–36 years with a mean of 27.5 years) participated in this study. Nine patients had unilateral pain and trained their painful leg eccentrically, while six had bilateral pain and trained one leg eccentrically and the other concentrically. Quadriceps muscle training was performed on a Kin-Com dynamometer at 90°/s and 120°/s angular velocity twice a week for 8 weeks. Before and after the treatment period the thigh muscle torques were measured on the Kin-Com dynamometer at 60°/s, 90°/s, 120°/s and 180°/s for quadriceps and at 60°/s and 180°/s for hamstrings. Nine controls, matched for gender and age with the group with unilateral pain, were tested in the same way on the Kin-Com dynamometer. For functional evaluation a knee score was calculated before training, after 8 weeks of training and at a mean of 3.4 years after completion of the training. After 8 weeks of training and at follow-up times of 1 and 3.4 years the patients were also questioned regarding whether or not they felt improvement from the training programme. To determine the degree of knee pain during the training Borg's pain scale was used. The results showed that, compared with the controls, the patients had a significantly lower knee extensor torque in their painful leg at all velocities measured. The greatest difference was found during eccentric actions. However, in comparison with the controls there were no significant differences in eccent ic and concentric knee flexor torques. After training there was a significant increase particularly in eccentric but also in concentric torque of the knee extensor in the painful leg of the eccentrically trained group. Of the six patients in the bilateral training group there were five who increased their concentric knee extensor torque and three who increased their eccentric torque. There were no significant differences in concentric and eccentric knee flexor torques before and after training in either of the legs in both training groups. The hamstring/quadriceps ratio was significantly higher in the patients' painful leg before training. However, due to increased quadriceps strength the hamstring/quadriceps ratio dropped after training. Patients in both groups reported no pain or mild pain during the training sessions. The eccentrically trained group was significantly improved both after 8 weeks of treatment and at follow-up 3.4 years later as evaluated using the knee score. The bilaterally trained group was significantly improved 3.4 years after completion of the training programme as evaluated using the knee score.     

等速离心训练对肩关节内外旋肌的肌力平衡及神经肌肉控制能力的影响

背景 肩关节内外旋肌肌力失衡会增加肩部运动损伤的风险,研究等速离心训练(IET)能否提高肌力平衡并改善神经肌肉控制能力具有重要的损伤预防意义。目的 探讨IET对健康青年人肩关节内外旋肌的肌力平衡及神经肌肉控制能力的影响。方法 2020年12月至2021年11月在复旦大学附属中山医院招募32例健康青年志愿者为研究对象,随机将其分为试验组(n=16)和对照组(n=16)。试验组接受4周IET,对照组接受4周连续被动运动训练(2次/周)。采用Biodex System 4 Pro多关节等速肌力测试与训练系统(美国Biodex公司)对两组研究对象的优势侧肩关节内、外旋肌群进行训练干预,分别在60(°)/s、120(°)/s速度下进行,干预前1周、干预结束后1周对两组肩关节内外旋肌的功能性比率(FR)、加速时间(AT)和达峰力矩时间(TPT)进行评估并比较。结果 试验组全部完成了4周的训练干预和评估,对照组2例中途退出。最终共30例研究对象数据纳入统计学分析。在60(°)/s和120(°)/s速度下,试验组干预后FR高于对照组(P<0.001),试验组干预后FR高于干预前(配对t检验：t<...     

Effect of isometric and isokinetic muscle training on static strength and dynamic power

Summary This study investigated whether isokinetic strength training might induce changes in static and dynamic power already achieved as a result of isometric strength training. The subjects were twelve males. The isometric strength and dynamic power of elbow flexors were tested by means of an electric dynamometer and fly-wheel every two weeks. During the first 8 weeks all subjects trained the elbow flexors isometrically at four different positions of elbow joints. This training produced 27–36% gains in isometric strength and 34–46% in power. Thereafter the subjects were divided into two groups: the FG group who trained isokinetically at a fast velocity of 157·s^–1, and the SG group at slow velocity of 73·s^–1. After 6 weeks of training, the FG group produced a significant gain in power with light equivalent masses and the SG group did so with heavy equivalent masses. Neither group showed change in isometric strength.     

Muscular fatigue during repeated isokinetic shoulder forward flexions in young females

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.     

Relationship between passive properties of the calf muscles and plantarflexion concentric isokinetic torque characteristics

The purpose of this study was to use a model of aging to examine the relationships between passive properties of the calf muscles and plantarflexion concentric isokinetic torque characteristics. Eighty-one active women 20–84 years of age were tested using a Kin-Com isokinetic dynamometer interfaced with electromyography (EMG). The passive properties were tested by stretching the muscles from relaxed plantarflexion to a maximal dorsiflexion (DF) angle at a rate of 5°·s^–1 (0.087 rad·s^–1) with minimal raw EMG activity (<0.05 mV). The maximal concentric torque was tested from maximal passive DF into plantarflexion at four randomly ordered velocities of 30, 60, 120, and 180°·s^–1. Pearson correlation coefficients (Bonferroni adjusted) indicated a hierarchical order of high to moderate positive correlations between four passive properties and the peak and mean concentric torque for all test velocities. Correlation coefficients for the four passive properties ranged from 0.50 to 0.78 (P<0.001), and the coefficients of determination (r ²) from higher to lower were: (1) maximal DF passive resistive torque (r ²: 0.50–0.62), (2) length extensibility (r ²: 0.40–0.49), (3) maximal muscle length (r ²: 0.28–0.41), and (4) passive elastic stiffness in the last half of the full-stretch range of motion (r ²: 0.25–0.31). The maximal DF passive resistive torque and the length extensibility accounted for 50–62% and 40–49% of the variability in the concentric torque, respectively. The results indicate that the concentrically stronger calf muscles of active women were positively correlated with passively stronger, longer, and stiffer calf muscles, which are characteristics of the calf muscles of younger women. Further studies are needed to examine whether therapeutic interventions, such as stretching and strengthening, can promote adaptations in the calf muscles of older women to attain these more youthful characteristics. Electronic Publication     

Effects of Kinesio tape application to trunk isokinetic strength in female participants

ABSTRACT

The purpose of this study is to analyse the effects of KT on trunk strength with respect to different angular speeds when applied to the trunks of healthy women. Forty healthy female participants were randomly distributed into two groups: the placebo group (PG) in which placebo KT was applied and the experimental group (EG). Participants’ trunk concentric flexion and extension muscle strength were measured using an isokinetic dynamometer in two different angular speeds (60°/s ? 180°/s). In both PG and EG groups, there was no significant difference measured immediately after taping at the two angular speed values. In the measurements taken 48 h later, as regards PG trunk flexion, extension muscle strength increased significantly (p = 0.0001) at 60°/sc. angular speed while, for the EG only, the strength of trunk extension muscle increased significantly (p = 0.002). It was observed, that to ensure an increase in strength, waiting for a certain length of time was required. Lower angular speeds and short-term applied KT improved the strength of the trunk extension muscle.     

膝骨关节炎与膝关节伸、屈肌群肌力的相关性研究

目的通过研究膝骨关节炎(knee osteoarthritis,KOA)症状及病变阶段与膝关节伸、屈肌群肌力的相关性,探讨KOA患者肌力训练的关键肌群。方法社区募集健康老年人、单膝KOA患者、双膝KOA患者共99位志愿者,应用膝关节等速肌力测试、WOMAC评分、6 min步行测试、CS-30测试,分析志愿者膝关节伸、屈肌群峰力矩与KOA症状、全身有氧运动能力、关节功能等的相关性。结果单膝KOA组患者患侧膝关节伸肌群等速峰力矩显著低于健侧。双膝KOA组患者症状严重侧和症状较轻侧膝关节伸、屈肌群等速峰力矩差异均有统计学意义。双膝KOA组患者膝关节伸肌群等速峰力矩显著低于健康组。KOA患者膝关节伸、屈肌群等速峰力矩与CS-30测试、6 min步行测试均呈正相关,均与年龄呈负相关;膝关节伸肌群等速峰力矩与WOMAC评分的疼痛和功能障碍项呈负相关。结论膝关节伸、屈肌群均与KOA相关,KOA康复过程中不仅需重视股四头肌等伸肌群的训练,而且要兼顾腘绳肌、腓肠肌等屈肌群的训练。     

Analyse vidéographique 2D d’exercices fonctionnels avec déplacements verticaux et mesure de la force musculaire isocinétique du genou après ligamentoplastie du ligament croisé antérieur

Introduction

After anterior cruciate ligament (ACL) ligamentoplasty, muscular recovery is often compared to asymmetries in monopodal length jumps, but rarely to functional exercises with vertical displacements. The objective of this study is to analyze these asymmetries and to determine the correlations with the muscular force.