Absolute reliability of isokinetic knee flexion and extension measurements adopting a prone position

The main purpose of this study was to determine the absolute and relative reliability of isokinetic peak torque (PT), angle of peak torque (APT), average power (PW) and total work (TW) for knee flexion and extension during concentric and eccentric actions measured in a prone position at 60, 180 and 240° s^?1. A total of 50 recreational athletes completed the study. PT, APT, PW and TW for concentric and eccentric knee extension and flexion were recorded at three different angular velocities (60, 180 and 240° s^?1) on three different occasions with a 72‐ to 96‐h rest interval between consecutive testing sessions. Absolute reliability was examined through typical percentage error (CV_TE), percentage change in the mean (ChM) and relative reliability with intraclass correlations (ICC_3,1). For both the knee extensor and flexor muscle groups, all strength data (except APT during knee flexion movements) demonstrated moderate absolute reliability (ChM < 3%; ICCs > 0·70; and CV_TE < 20%) independent of the knee movement (flexion and extension), type of muscle action (concentric and eccentric) and angular velocity (60, 180 and 240° s^?1). Therefore, the current study suggests that the CV_TE values reported for PT (8–20%), APT (8–18%) (only during knee extension movements), PW (14–20%) and TW (12–28%) may be acceptable to detect the large changes usually observed after rehabilitation programmes, but not acceptable to examine the effect of preventative training programmes in healthy individuals.     

等速测试技术的临床应用研究

评价等速运动技术的临床应用价值，探讨其生理学基础。方法用Ｃｙｂｅｘ－６０００型等速肌力测试系统测试２２２例各种运动系统后患者的肌肉功能。结论：等速肌肉测试技术是一种全新的肌肉功能评价方法，可提供可靠的量化指标。     

膝关节骨性关节炎等速肌力测试的研究

运用Ｃｙｂｅｘ－６０００型等速测力系统对３４名膝关节骨性关节炎（ｏｓｔｅｏａｒｔｈｒｉｔｉｓ，ＯＡ）患者的两侧膝伸肌和屈肌进行肌力测试。结果表明患膝屈肌和伸肌的峰力矩在不同运动速度下（６０°／ｓ，１２０°／ｓ和１８０°／ｓ）均较健侧明显下降，尤以６０°／ｓ时峰力矩下降明显。患膝屈肌和伸肌峰力矩出现的时间与健侧相比有延迟趋势。由于患膝屈肌力和伸肌力同步下降，屈肌、伸肌峰力矩比值与健侧相比无明显差异。认为对膝ＯＡ患者的肌力训练，应同时考虑伸膝力和屈膝力的训练，以便提高肌力，改善关节稳定性。     

Clinical uses of isokinetic measurements. Critical issues

Isokinetic measurements are widely used by physical therapists for evaluation and treatment planning. We believe that some use of isokinetic measurements is unwarranted in view of the paucity of credible scientific research on these measurements. With increased emphasis from third-party payers and from the medical community for documentation of the effectiveness of physical therapy services, we believe that therapists must be aware how they can and cannot use isokinetic measurements in their clinical settings. Concepts that relate to isokinetic testing are discussed and critically examined.     

3种姿势对高血压病人血压测量值的影响

血压测量受很多因素影响,其中包括体位姿势、环境等因素。因此被认为是执行最不准确的检查之一[1]。血压测量指南中对血压测量的体位也没有明确的规定,通常认为测量血压时,只要病人测量的上臂放在心脏水平,则可以取坐位、卧位和     

Reliability of measurements of concentric and eccentric isokinetic loading

The purpose of this study was to assess the reliability of a method for testing peak torque and work output of the knee extensor muscle during concentric and eccentric loading at three velocities of exercise (60 degrees, 120 degrees, and 180 degrees/sec). Fourteen healthy men (23-32 years of age) performed exercises of the quadriceps femoris muscles during concentric and eccentric loading, with a five-second pause between each contraction. Three different tests were performed on different occasions. The first exercise session was a practice session, and the next two sessions were established to collect data in a test-retest format. Peak torque and work were measured for the two testing sessions. The results of this study demonstrated that with a very specific protocol, the reliability of concentric peak torque and work measurements was excellent at 60 degrees and 120 degrees/sec and good at 180 degrees/sec. In contrast, reliability of eccentric peak torque and work measurements was good at 120 degrees and 180 degrees/sec but low at 60 degrees/sec.     

速度因素对躯干等速肌力测试影响的研究

研究速度因素对躯干等速肌力测试的影响,探讨等速肌力测试用于躯干肌肌力评定的最佳速度参数。方法:健康男性30例,使用美国产BIODEXⅡAP多关节等速测试及康复系统测定躯干峰力矩(PT)、相对峰力矩(PT/BW)、总功(TW)、相对总功(TW/BW)、功率(AP)和屈/伸比值(F/E),测试角速度分别选用60°/s、180°/s和240°/s,利用单因素方差分析和SNK-q检验对结果进行统计学分析。结果:各组间的PT、PT/BW、TW/BW和AP比较差异有显著性意义(P<0.05),60°/s组PT、PT/BW、TW/BW和AP同180°/s组比较差异显著(P<0.05),而180°/s组同240°/s组比较差异无显著性意义(P>0.05)。结论:速度对躯干肌肉的等速肌力测试的影响是明显的,进行测试和训练时,选择低速指标比较可靠。     

Influence of ventilatory settings and sampling position on measurements of simulated exhaled nitric oxide levels

Chronic lung disease is a common adverse outcome of prematurely born infants and is associated with an early inflammatory response, which persists over weeks. As a consequence, it is possible that exhaled nitric oxide levels might be raised in affected infants. The majority of such infants will be ventilated in the first weeks of birth and thus it is important to determine the influence of mechanical ventilation on nitric oxide levels. As a consequence, our aim was to determine whether, during mechanical ventilation, simulated exhaled nitric oxide levels were influenced by changes in ventilator settings or the sampling catheter position. A lung model was created consisting of a rubber bag inside a 11 jar. An endotracheal tube (ETT) was fixed securely within the neck of the bag. Nitric oxide was delivered into the bag at a constant rate to simulate production and sampled from within the ETT and the bag. The sampled nitric oxide was analysed using a Sievers chemiluminescence analyser. The ETT was attached to a neonatal ventilator and a nitric oxide scavenger placed in the ventilator's inspiratory limb to ensure nitric oxide free gas was delivered. Comparison of different sampling positions revealed that the highest peak nitric oxide level within the ETT was at the tip. Increasing peak inflating pressure and ventilator rate resulted in a decrease in the peak nitric oxide levels. Increasing the inspired oxygen concentration also was associated with a reduction in the peak nitric oxide levels, the effect being more pronounced when larger volume lung models were examined. The results emphasized that the conditions of measurement must be standardized in infants receiving respiratory support, if exhaled nitric oxide results are to be appropriately interpreted.     

Reliability of isokinetic measurements of hip muscle torque in young boys

The purpose of this study was to determine the reliability of measurements of hip muscle torque obtained with the Cybex II isokinetic dynamometer from healthy young boys. Twenty-nine healthy boys, aged 6 to 10 years, were tested two times at one- to two-week intervals. Torque of the hip flexors and extensors and the hip abductors and adductors was assessed at angular velocities of 30 degrees and 90 degrees/sec. The torque generated by each muscle group at 30 degrees/sec was similar to the torque generated at 90 degrees/sec. Intraclass correlation coefficients (ICCs) were used to determine test-retest reliability for measurements of each of the muscle groups at both angular velocities. The ICCs were higher for hip flexion and extension than they were for hip abduction and adduction. The highest ICC (ICC = .84) was found for hip extension at 90 degrees/sec. The ICCs for hip abduction and adduction at both angular velocities were less than .60. Factors that possibly contributed to the relatively low reliability in hip abduction and adduction are discussed.     

躯干肌慢速等速向心收缩肌力的测试研究

目的:研究不同速度对躯干肌慢速等速肌力测试的影响,探讨用于躯干肌肌力评定的慢速等速肌力测试合理的速度参数。方法:健康受试者43例,使用美国产BiodexⅡAP型多关节等速测试系统测定躯干肌峰力矩(PT)、相对峰力矩(PT/BW)、总功(TW)、相对总功(TW/BW)和屈伸比值(F/E),测试角速度分别选用30°/s和60°/s。结果:伸展收缩测试时两组间的PT、PT/BW、TW和TW/BW比较差异有显著性意义(P<0.05),屈曲收缩测试时上述指标比较差异无显著性意义(P>0.05),两组间F/E差异有显著性意义(P<0.05)。结论:躯干肌慢速等速测试中,速度明显影响伸展测试值,30°/s比60°/s等速测试似更能反映躯干肌的力学特征,而对屈曲测试值的影响并不明显,在慢速范围内,屈肌肌力测试值似处于稳定的峰值状态。     

Reproducibility of isokinetic muscle strength measurements in normal and arthritic individuals

The serial reproducibility of an individual's isokinetic torque was assessed in order to establish a reliable baseline value for future comparison. Thirty-two controls and twenty arthritic patients were tested for their peak isokinetic torque on knee flexion and extension and hip flexion at three velocities on five occasions, at fortnightly intervals. The first test was found to provide a reliable baseline for controls and subjects who could generate a peak torque of 54 Newton meters (Nm) or more. The second test was found to be more representative of the series for groups containing weaker subjects. Variation related to torque: for subjects who generate a peak torque of 54 Nm or more, a range of +/- 20% accommodates the variability of 95% of tests. We conclude that a +/- 20% range applied to either the first or second test, depending on the nature of the group to be studied, serves as a representative baseline value.     

Effect of lumbar lordotic angle on lumbosacral joint during isokinetic exercise: A simulation study

Background

It is important to consider lumbar lordotic angle for setup of training program in field of sports and rehabilitation to prevent unexpected posture deviation and back pain. The purpose of this study was to to analyze the biomechanical impact of the level of lumbar lordosis angle during isokinetic exercise through dynamic analysis using a 3-dimensional musculoskeletal model.

Methods

Gait analysis and isokinetic exercise for the healthy adults (n = 10) were performed to design a 3-dimensional musculoskeletal model and then we made each model for normal lordosis, excessive lordosis, lumbar kyphosis, and hypo-lordosis according to lordotic angle and inputted experimental data as initial values to perform inverse dynamic analysis to quantify muscle joint torque, joint forces of each joint, system energy, and estimated muscle forces at lumbosacral joint.

Findings

Comparing the joint torques, the largest torque of excessive lordosis was 16.6% larger than that of normal lordosis, and lumbar kyphosis was 11.7% less than normal lordosis. There existed no significant difference in the compressive intervertebral forces of each lumbar joint (P > 0.05), but statistically significant difference in the anterioposterior shear force (lumbar kyphosis > hypo-lordosis > excessive lordosis > normal lordosis, P < 0.05). Lastly, lumbar kyphosis required the least and most energy during flexion and extension respectively.

Interpretation

During the rehabilitation process, more efficient training will be possible by taking into consideration not simply weight and height but biomechanical effects on the skeletal muscle system according to lumbar lordortic angles.     

Efficacy of isokinetic exercise on joint position sense and muscle strength in patellofemoral pain syndrome

OBJECTIVE: The objective of this study was to demonstrate the impairment of knee joint position sense in individuals with patellofemoral pain syndrome and investigate the effects of isokinetic exercise on knee joint position sense and muscle strength. DESIGN: A total of 24 male patients complaining of anterior knee pain caused by overexertion and 24 male healthy individuals without symptoms were included for this investigation. Isokinetic exercise protocol was carried out at angular velocities of 60 degrees/sec and 180 degrees/sec. These sessions were repeated three times per week and lasted for 6 wks. At the beginning and after 6 wks of knee passive joint position sense, quadriceps and hamstring muscle strength and pain assessments were performed. RESULTS: After the isokinetic exercise, flexion peak torque (P < 0.05), extension peak torque (P < 0.01), flexion total work (P < 0.001), extension total work (P < 0.001), passive reproduction of knee joint position sense for 40 degrees of flexion (P < 0.05) and 50 degrees of extension (P < 0.01), and pain score (P < 0.001) improved significantly in the patellofemoral pain syndrome group. CONCLUSION: Isokinetic exercises have positive effects on passive position sense of knee joints, increasing the muscular strength and work capacity. These findings show that using the present isokinetic exercise in rehabilitation protocols of patients with patellofemoral pain syndrome not only improves the knee joint stabilization but also the proprioceptive acuity.     

Differentiation of maximal and submaximal knee extension efforts by isokinetic testing

The variability of torque produced during maximal and subject selected submaximal isokinetic knee extension efforst was compared. Subjects were 40 healthy volunteers (20 men and 20 women). Following three warm-up efforts subjects randomly performed one set of both four repeated maximal and submaximal knee extension efforts at 60°/s. Torque was measured at 30 and 45° of flexion and corrected for gravity. Variability of torque was examined by first calculating for each subject the mean, standard deviation (s.d.), and coefficient of variation (CV) for the four trials under the maximal and submaximal conditions. The s.d. was used to represent the absolute variation from the mean, whereas the CV was used to represent the relative variation from the mean. The CVs and s.d.s were compared between the maximal and submaximal efforts using analysis of variance. Variability, as demonstrated by s.d.s, was not consistently greater during submaximal than during maximal efforts. Variability, as demonstrated by CVs, was significantly greater during submaximal than during maximal efforts. In spite of finding statistical differences in the variability of maximal and submaximal efforts, no clear cut-off was identified above and below which performance could be dichotomized into the submaximal and maximal groups based on variability.

Relevance

Although the variability of angle specific knee-extension torques is greater during submaximal than during maximal efforts, the range of variability associated with maximal and submaximal efforts does not appear to be mutually exclusive. Therefore clinicians should exercise caution in judging the sincerity of an individual's maximal effort based solely on isokinetic measurement variability.     

Anatomical measurements of porcine lumbar vertebrae

BACKGROUND: Porcine spines are frequently used as an alternative to human specimens for spinal implant testing. Morphometric data of the normal porcine lumbar vertebrae are lacking at this time, yet these data are crucial for application to such studies. This study provides such a database and highlights the differences between porcine and human specimens. METHODS: All the lumbar vertebrae (L1-L6) from six adult (18-24 month old, 60-80 kg) male porcine spines were used in our study (n=36). A total of 15 anatomical parameters from each vertebra were measured by two observers. Linear parameters were measured using digital calipers. The mean, standard deviation and standard error of mean were calculated using Microsoft Excel. Results from our study were compared with available data on human vertebra. FINDINGS: Compared to the human vertebrae, there were several anatomical differences in the porcine thoracolumbar vertebrae including smaller end plate area, larger pedicles, taller and narrower vertebral bodies, narrower spinal canals and smaller spinous process lengths. INTERPRETATION: Our results provide a database of anatomical measurements for porcine lumbar vertebrae and highlight their differences with human vertebrae. Porcine vertebrae may be used as an alternative to human specimen if these differences are taken into account. Studies which involve testing implants such as interbody cages, disc replacements and pedicle screw-rod systems in porcine spines should match implant size appropriately.     

腰屈伸等速向心收缩肌力测试的效度研究

目的：研究腰屈伸的等速肌力测试效度,研究合适的角速度测试。方法：由同一个测试人员对30例正常无腰痛的自愿者、60例普通慢性腰痛患者及30例运动员慢性腰痛患者进行腰屈伸的等速肌力测试,并同步采用表面肌电图对相关肌群进行检测,对腰屈伸的等速肌力以三种不同角速度测试进行效度分析。结果：60°/s和90°/s的效度满意;180°/s的效度不理想[普通腰痛组中绝大多数患者腰屈曲和腰伸展时的峰力矩（PT）、总功（TW）和平均功率（AP）均为0,呈典型的“地板效应”]。结论： 对正常人进行腰屈伸的等速肌力测试时可以使用     

Continuous versus separate isokinetic test protocol: the effect of estradiol on the reproducibility of concentric and eccentric isokinetic measurements in knee muscles.

OBJECTIVE: To investigate the effects of estradiol on the reliability of concentric and eccentric isokinetic measurements of knee muscles and to compare the reproducibility of measurements in a continuous test protocol and a separate test protocol. DESIGN: Repeated measurements. SETTING: A university exercise physiology laboratory. PARTICIPANTS: Twenty healthy sedentary women volunteers, aged 19 to 37 years, who had regular menstrual cycles (ranging from 27 to 35 days). Subjects were randomly divided into two groups: continuous test group (n = 10) and separate test group (n = 10) and tested at the menstrual phase (days 1 to 3) and preovulatory phase (days 12 to 14) in both legs. METHODS: Continuous reciprocal flexion-extension contractions were used in the continuous test group, and separated flexion and extension contractions were used in the separate test group. Four different test protocols were designed to determine the effects of test mode and number of contractions on the isokinetic measurements: Group A, 4 reciprocal flexion-extension repetitions at each angular velocity of 60 degrees/sec and 180 degrees/sec in one leg in the continuous test group; Group B, 4 and 20 reciprocal flexion-extension repetitions at 60 degrees/sec and 180 degrees/sec, respectively, in the contralateral leg in the same group; Group C, 4 repetitions in extensors and flexors at each angular velocity of 60 degrees/sec and 180 degrees/sec with a 5-minute rest between the two muscle groups in one leg in the separate test group; and Group D, 4 repetitions at 60 degrees/sec and 20 repetitions at 180 degrees/sec for extensors and flexors with a 5-minute rest between the two muscle groups in the contralateral leg in the same group. Blood samples were analyzed for sex hormones, creatine kinase, and lactate dehydrogenase before the tests at the menstrual phase and the preovulatory phase. In addition subjective assessment of muscle soreness was made at each blood sampling. RESULTS: Concentric and eccentric peak torque, average power, total work, and endurance ratio at both angular velocities were not significantly different in the two phases of the cycle by paired observation t test for each of the four groups. Except for concentric and eccentric endurance ratios of quadriceps and hamstrings, and concentric peak torque and average power of hamstrings at 180 degrees/sec in Group D, intraclass correlation coefficients of tested variables showed correlations that were moderate to excellent (p < .05) between two phases. In addition, there were no significant correlations between estradiol and the tested variables. Resting serum creatine kinase and lactate dehydrogenase activities and the score of muscle soreness were at the baseline and not significantly different prior to the tests performed at preovulatory and menstrual phases. CONCLUSIONS: The results suggest that: (1) reproducibility of isokinetic tests during the menstrual cycle is not influenced by sex hormone fluctuations, particularly estradiol; (2) when compared with the separate test protocol used in this study, the continuous test protocol is more appropriate to measure peak torque, average power, total work, and endurance ratio for both muscle groups of the knee even if the number of contractions is changed. However, these conclusions are specific to sedentary individuals; to make more valid conclusions, further studies with different subject groups are needed.     

Influence of age and physical activity on isokinetic characteristics of hamstring and quadriceps muscles of young gymnasts and soccer players]

OBJECTIVE: The aim of this work is the assessment of age and sport influences on the isokinetic knee muscle characteristics. SUBJECTS AND METHOD: Subjects performed a bilateral knee flexion/extension test on an isokinetic device at 60 and 180 degrees.s(-1) speed in concentric mode. The three parameters studied in this work were the Peak Torque, Average Power and hamstring/quadriceps ratio. Thirty-eight soccer players (16,6 +/- 1.4 years old) and 22 gymnasts (18 +/- 2.8 years old) were tested. The population was separated into three groups : 15 years old, 17 years old, 20 years old. RESULTS: The isokinetic values of soccer players were significantly higher (p < 0.0001) than those of the the gymnasts. The isokinetic values of the oldest soccer players were significantly higher (0.005 < p < 0.05) for hamstrings than those of the younger soccer players. The isokinetic values of the oldest gymnasts were significantly higher (0.005 < p < 0.05) for the quadriceps than those of the younger gymnasts. There were no significant differences between dominant and non dominant limbs in soccer players. CONCLUSION: In the present study, the muscular maturation improves the absolute strength of the older sportsmen in comparison to the younger. Soccer favor most the absolute strength of the inferior member in comparison to the gymnastics.