前交叉韧带损伤并发或不并发髌股关节软骨损伤等速角度力矩曲线的差异

目的 探讨前交叉韧带损伤并发或不并发髌股关节软骨损伤患者的等速角度力矩曲线差异。方法 回顾分析2018年9月至2019年9月行膝关节镜探查术并在术前行等速肌力测试的患者,选取年龄、性别、半月板损伤相匹配的前交叉韧带损伤并发或不并发髌股关节软骨损伤患者各17例。术前采用等速肌力测试仪进行180°/s、60°/s的膝关节等速和等长屈伸测试。采用1°递增的平均力矩结果进行标准化(力矩/体质量),比较两组间角度力矩曲线差异。结果 180°/s下,两组间健侧和患侧屈膝力矩比较均无显著性差异(P > 0.05);两组间健侧伸膝力矩比较无显著性差异( P > 0.05),患侧伸膝力矩在88°~90°有显著性差异( t > 2.102, P < 0.05),余角度均无显著性差异( P > 0.05)。60°/s下,两组间健侧屈膝力矩在62°~82°有显著性差异(| t| >2.056, P < 0.05),余角度无显著性差异;两组间患侧屈膝力矩比较无显著性差异( P > 0.05);两组间健侧和患侧伸膝力矩比较均无显著性差异( P > 0.05),但无软骨损伤的伸膝力矩有高于髌股软骨损伤的趋势。在180°/s等速屈伸力矩曲线的起始阶段会出现一个曲线变化。髌股软骨损伤组患侧等长伸膝力矩明显小于无髌股软骨损伤组( t = 2.858, P < 0.01),两组间患侧等长屈膝及健侧屈、伸力矩比较无显著性差异( t < 1.905, P > 0.05)。 结论 前交叉韧带损伤并发髌股软骨损伤较不并发髌股软骨损伤患者的等速运动速度越低,力量差异越显著。并发髌股软骨损伤的前交叉韧带损伤患者训练力量时建议采用高速运动。     

Differences in elbow flexion torque measured concentrically, eccentrically, and isometrically

The purposes of this study were to describe torque-velocity relationships during concentric, eccentric, and isometric testing of elbow flexor muscles and to determine test-retest reliability of a specific isokinetic testing protocol. Thirty healthy women were tested using an isokinetic dynamometer at velocities of 0 degrees, 30 degrees, 120 degrees, and 210 degrees/sec. Reliability was assessed in 20 of the subjects by retesting concentric and eccentric torques at 30 degrees and 120 degrees/sec after a 30-minute rest interval. The highest torque from three maximal efforts was considered to be peak torque. Mean eccentric peak torque was greater than either isometric or concentric peak torque; as isokinetic test velocity increased, the differences between concentric and eccentric torques became larger. Intraclass correlation coefficients ranged from .72 to .83, indicating lack of consistency between test and retest torques. Consecutive concentric-eccentric testing and lack of mechanical stabilization might have contributed to test-retest variability and to the relatively small differences between concentric and eccentric torques. Continued study of reliability of isokinetic testing protocols and further investigation of concentric-eccentric torque-velocity relationships are advocated.     

The relationships of functional capacity, pain, and isometric and isokinetic torque in osteoarthrosis of the knee

Thirty-nine patients suffering from osteoarthrosis of the knee were repeatedly measured. The relationship was studied for two groups of variables. The first group consisted of subjective assessments of functional capacity and pain and a walking test. The second group consisted of isometric knee extension torque and isokinetic knee flexion and extension torque at 30 degrees/sec, 60 degrees/sec, 120 degrees/sec and 180 degrees/sec. High correlations between each of the static and dynamic torque values were found. Multiple regression analysis showed that isometric and isokinetic torque measures are unsatisfactory predictors of functional capacity, since only 23-35% of the variation of functional capacity, pain and walking test variables was explained by the variation of torque variables. Dynamic torque measurements had very little advantage over static torque tests. It is concluded that outcome measures in studies of osteoarthrosis should be problem-oriented and include direct assessments of functional capacity, pain and walking ability.     

Is quadriceps muscle strength a determinant of the physical function of the elderly?

[Purpose] To determine the relationships of the quadriceps rate of torque development and the time to peak torque with the physical function of the elderly. [Subjects and Methods] Twenty-one subjects participated in this study. Quadriceps strength was measured using isometric and isokinetic torque tests. Time to peak torque and rate of torque development were calculated from the torque time curve of the isokinetic and isometric torque tests, respectively. Physical activities were measured using 4 physical activity tests. Pearson correlation coefficients were used to examine the relationships among the variables. [Results] The time to peak torque showed significant correlations with all measures of physical activity tests. Rate of torque development showed significant correlation with the timed stair-climbing test. Isometric and isokinetic torques had no significant correlations with any of the physical activity tests. [Conclusion] Time to maximum torque and the rate of torque development might be more important than peak torque in determining the physical function of the elderly.Key words: Elderly, Rate of torque development, Quadriceps muscle strength     

Measurement of torque of trunk flexors at different velocities.

The purpose of this study was to determine the test-retest reliability of recording isometric and isokinetic torque of the trunk flexors and to examine the effect of velocity on the torque curves. Thirty healthy subjects were tested on two occasions for isometric torque of trunk flexion at four angles and eccentric and concentric torque at three velocities. Two subjects repeated these tests in the passive mode to determine the torque produced by the trunk when there was no active flexion effort. Intraclass correlation coefficients were above 0.85 for all isometric and isokinetic measures. Standard errors of measurement ranged from 6.9 to 19.5 Nm. Student t-tests indicated no significant differences between occasions for all outcome measures. Examination of passive and active torque curves indicated that the torque produced by the mass of the trunk increased with increasing velocity. It is concluded that both isometric and isokinetic testing of the trunk flexors are reliable, but that testing at higher velocities may not provide a valid measure of muscle performance.     

Rate of isometric knee extension strength development and walking speed after stroke

The relationship between lower-limb weakness and walking speed after stroke is not clear. This may be related to the measurement used to quantify weakness, typically peak strength. This study examined the relationship between two measures of isometric knee extension strength, i.e., peak torque and the rate of torque development and walking speed in adults with stroke. This study had 83 stroke survivors who participated. For the affected lower limb, rate and peak torque explained 12% of the variance in gait speed. Removing rate from the model significantly reduced the explained variance; in contrast, removing peak torque did not reduce the variance. For the less affected lower limb, rate tended to be more predictive of gait speed than peak torque. Diminished ability to rapidly generate knee extension torque contributes more to decreased walking speed after stroke than does maximal strength. Of note, 88% of the variance in gait speed is not explained by rate and peak isometric knee extension strength. Further studies are needed to determine if rehabilitation poststroke can increase the rate of knee strength development and if it results in faster walking speeds.     

Obtaining reliable measurements of knee extensor torque produced during maximal voluntary contractions: an experimental investigation.

The purpose of this study was to develop and test a protocol that could be used to obtain reliable measurements of knee extensor torque produced during maximal voluntary contractions. On each of 3 days, 10 subjects performed six consecutive maximal voluntary contractions, in the same randomized order, for each of the following 10 conditions: concentric isokinetic contractions at velocities of 30 degrees, 90 degrees, 120 degrees, and 180 degrees/s; eccentric isokinetic contractions at velocities of 30 degrees, 90 degrees, 120 degrees, and 180 degrees/s; and isometric contractions at 40 and 60 degrees of knee flexion. The peak torques produced were examined to determine on which day and during which contraction subjects produced the greatest torques for each condition. This information was used to develop a practice protocol. Fifteen different subjects were tested following this protocol. Subjects participated in two practice sessions, a test session, and a retest session. Intraclass correlation coefficients (ICCs) were calculated to determine the degree of agreement between torques for the test and retest sessions. The ICCs ranged from .87 to .98. The protocol developed appears to be useful for obtaining reliable measurements of knee extensor torque.     

Isometric and isokinetic measurement of hamstring and quadriceps strength.

This study evaluates quadriceps strength at varying movement velocities in a group of healthy subjects. Specific objectives included (1) investigating the effect of angular velocity on peak torque (PT) (2) investigating the effect of angular velocity on joint angle at peak torque (JAPT) and (3) evaluating whether the use of a relatively new isokinetic testing device yields new insights to previously accepted relationships between angular velocity and PT or JAPT. Twenty healthy subjects were tested for isometric and isokinetic knee extension and flexion strength on a LIDO Active Isokinetic Rehabilitation System at velocities of 0 degrees, 60 degrees, 120 degrees, and 180 degrees/sec. Isometric PT (0 degrees/sec) was found to be highly correlated with isokinetic PT for both extensors and flexors at all velocities (r = .88-.93, p less than .01). PT declined significantly as angular velocity increased for both extension (p less than .01) and flexion (p less than .05). A relationship between isometric and isokinetic JAPT was significant for extension only at 60 degrees and 180 degrees/sec (r = .48-.52, p less than .05). These results indicate that knee isometric and isokinetic PT as measured on the LIDO Active system are highly related for both extension and flexion. PT declined as isokinetic angular velocity increased. Isometric and isokinetic JAPT are significantly related only for extension.     

Isokinetic strength training in below-knee amputees

Eight below-knee amputees performed isokinetic training of knee extensor- and knee-flexor muscles for a period of 8-12 weeks at angular velocities of 60 degrees/s, 180 degrees/s and 240 degrees/s. Before and after training isokinetic and isometric knee extensor/flexor strength was measured. Muscle biopsies were taken from the vastus lateralis and the cross-sectional area of the thigh muscles was measured with computerized tomography. Peak torque of the amputated leg increased significantly in all knee-extension tests and in knee-flexion at 180 degrees/s, and in the non-amputated leg in extension at 180 degrees/s, 240 degrees/s and for isometric strength at 60 degrees knee angle. Knee-flexion strength increased at 240 degrees/s. The cross-sectional area of the muscle fibers increased in the amputated leg in all patients except one. There was no significant increase in the non-amputated leg which also was trained. The quotient between the cross-sectional areas of type II and type I fibers increased from 1.04 to 1.20 in the amputated leg, demonstrating an increase specially in the type II fibers. There was no difference in the non-amputated leg. The cross-sectional area of the thigh muscles did not show any significant change in either leg. The patients estimated their ability to walk after training to more than double the distance compared to before training. They could also manage better without walking aids. The increase in strength and the synchronous increase in the size of type II (fast twitch) fibers indicate that the training model has activated also these motor units which probably have not been given as much training earlier.     

Importance of correcting isokinetic peak torque for the effect of gravity when calculating knee flexor to extensor muscle ratios

The purpose of our investigation was to compare, for the hamstring and quadriceps femoris muscles, peak torque values uncorrected for gravity with the peak torque values corrected for gravity and to determine the effect of making this correction on the hamstring to quadriceps femoris muscle peak torque ratio at slow and fast isokinetic speeds. We measured peak torques isokinetically at 60 degrees/sec (slow) and 240 degrees/sec (fast) in 25 female university soccer players. The gravity effect torque (GET) is the torque resulting from the effect of gravity on the combined weight of the leg and dynamometer arm at the precise angle of extension and flexion peak torque. The GET was added to the measured quadriceps femoris muscle peak torque and subtracted from the hamstring muscle peak torque to yield gravity corrected values. Failure to consider GET greatly underestimated quadriceps femoris muscle torque and overestimated hamstring muscle torque and the ratio between these torques at both speeds. Whereas the uncorrected hamstring to quadriceps femoris muscle peak torque ratio increased as speeds went from 60 degrees/sec to 240 degrees/sec, the gravity corrected ratio significantly decreased. Clinicians must remember the importance of making the gravity correction in patients with reduced torque output where the gravitational torque is a greater percentage of the measured torque to ascertain correctly the relative strength of antagonists inversely affected by gravity.     

Effect on maximal strength of submaximal exercise in Duchenne muscular dystrophy.

Four Duchenne muscular dystrophy patients, with quadriceps of at least antigravity strength, exercised one quadriceps submaximally 4 or 5 days per week for six months. The exercise was done under supervision and consisted of extending one knee from 90 degrees to full extension using the Cybex isokinetic exerciser. The other side was not exercised at all. The two sides were tested for maximal isokinetic strength monthly for twelve months and at 18 and 24 months after the beginning of the study. On the average, the exercised leg had a greater maximal torque both during and after the exercise period until the torques on both sides decreased to zero. The results indicate that submaximal exercise has no negative effect and may be of limited value in increasing strength in Duchenne muscular dystrophy.     

Determinants of maximum walking speed in hemiparetic stroke patients

The time necessary to walk 10 m with the fastest speed, the sway path of the center of feet pressure in station, and the isokinetic strength for knee extension of each side were examined in 29 hemiparetic stroke patients. The maximum walking speed of the patients was related to the sway path and the isokinetic muscle strength of affected side. The patients could be divided into two groups based on their sway path. The determinants of the maximum walking speed in the unstable group were the sway path and the isokinetic muscle strength of the both sides, whereas that in the stable group was only the isokinetic muscle strength of affected side.     

Effect of resisted knee flexion on knee extension torque

We tested the principle of "reversal of antagonists" by measuring the effect of resisted knee flexion on subsequent peak knee extension torque at velocities of 60 degrees/sec and 120 degrees/sec using an isokinetic dynamometer. We determined peak knee extension torques from torque curves produced during knee extension that was performed reciprocally with either passive or maximum voluntary resisted knee flexion. We used a crossover design so that all 18 healthy adult subjects performed knee extension reciprocally with both passive and resisted knee flexion. Paired means t tests revealed no statistically significant difference between the peak knee extension torques produced under the two knee flexion conditions either at 60 degrees/sec or 120 degrees/sec. We, therefore, concluded that resisted knee flexion does not augment peak knee extension torque under our conditions of testing. The concept of reversal of antagonists was not supported. Antagonistic muscle functioning, therefore, may be irrelevant to agonist isokinetic testing and training in neurologically healthy persons.     

Test-retest reliability of isokinetic muscle strength of the lower extremities in patients with stroke

OBJECTIVE: To i the test-retest reliability of isokinetic strength measurements of 3 muscle groups of the lower extremities in stroke patients. DESIGN: Isokineth tests of bilateral hip flexors, knee extensors, and ankle plantarflexors at 2 angular velocities, performed during 2 sessions scheduled 1 week apart for each subject. SETTING: Outpatilitation clinic of a local hospital in Taiwan. PARTICIPANTS: Nts with mild spastic hemiparesis secondary to stroke and with poststroke onset time of at least 6 months. All subjects could communicate and voluntarily move the affected lower extremity. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The maximal peak torque, total work, and average power of the 3 muscle groups on the affected side examined during each test were quantified by using the normalization and the deficit methods. The normalization method divides the measured strength value by the patient's body weight, whereas the deficit method divides the difference between the strengths of the unaffected and affected extremities by the strength of the unaffected extremity. RESULTS: The normalized strength measures for muscles on the affected side showed good to excellent test-retest reliability (intraclass correlation coefficient [ICC] range,.62-.94; P<.05), whereas the deficit strength measures did not always show good reliability (ICC range,.13-.91). The knee extensors and ankle plantarflexors, but not the hip flexors, on the affected side showed better test-retest reliability of isokinetic strength generated at faster velocity (ICC range,.73-.94) than that generated at slower velocity (ICC range,.62-.88). The normalized peak torque (ICC range,.76-.94) and total work (ICC range,.83-.91) were more reliable than the normalized average power (ICC range,.62-.90) for all 3 muscle groups on the affected side. CONCLUSIONS: Quantitative assessment of muscle strength of the affected lower extremity in patients with mild spastic hemiparesis secondary to stroke is feasible using isokinetic testing. However, the test-retest reliability of isokinetic strength measures is affected by the quantifying method, testing velocity, and strength measures.     

Reliability of knee extension and flexion measurements using the Con-Trex isokinetic dynamometer

The aim of this study was to evaluate the reliability of isokinetic and isometric assessments of the knee extensor and the flexor muscle function using the Con-Trex isokinetic dynamometer. Thirty healthy subjects (15 males, 15 females) were tested and retested 7 days later for maximal strength (isokinetic peak torque, work, power and angle of peak torque as well as isometric maximal voluntary contraction torque and rate of torque development) and fatigue (per cent loss and linear slope of torque and work across a series of 20 contractions). For both the knee extensor and the flexor muscle groups, all strength data - except angle of peak torque - demonstrated moderate-to-high reliability, with intraclass correlation coefficients (ICC) higher than 0.86. The highest reliability was observed for concentric peak torque of the knee extensor muscles (ICC = 0.99). Test-retest reliability of fatigue variables was moderate for the knee extensor (ICC range 0.84-0.89) and insufficient-to-moderate for the knee flexor muscles (ICC range 0.78-0.81). The more reliable index of muscle fatigue was the linear slope of the decline in work output. These findings establish the reliability of isokinetic and isometric measurements using the Con-Trex machine.     

Isometric hand grip strength correlated with isokinetic data of the shoulder stabilizers in individuals with chronic stroke

The purpose of this study was to examine the relationships between isometric hand grip (HG) strength and isokinetic strength data of the glenoumeral and scapulothoracic muscles in 12 individuals with chronic hemiparesis due to stroke. Measures of maximal grip strength were obtained on the HG dynamometer Jamar(?). Isokinetic measures of peak torque and work during shoulder rotations and scapular protraction-retraction movements were obtained with the isokinetic dynamometer at a speed of 60°/s. Pearson correlation coefficients between isometric HG and isokinetic strength data ranged between 0.60 and 0.82 for the peak torque and between 0.59 and 0.86 for the isokinetic work. The findings suggested that, in absence of isokinetic dynamometers, isometric HG strength measurements could be clinically used to monitor strength levels of the shoulder stabilizers and to guide load progressions during strengthening interventions for people with chronic hemiparesis.     

Age-related changes in hip abductor and adductor joint torques

OBJECTIVE: To test the hypothesis that older age significantly affects hip abduction and adduction joint torque-time generating capability in women. DESIGN: Cross-sectional study, wherein subjects were tested in a supported standing position. SETTING: University human performance laboratory. PARTICIPANTS: Seventy-six healthy, adult women (38 young; 38 old). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The dependent variables were peak isometric torque and its corresponding torque rate and average peak isokinetic torque. Age group differences were assessed by analysis of variance. RESULTS: Isometric peak torques were significantly lower in older women (P相似文献   

Trunk muscle strength in relation to balance and functional disability in unihemispheric stroke patients

OBJECTIVE: To evaluate trunk muscle strength in unihemispheric stroke patients and to assess how it relates to body balance and functional disability in this patient group. DESIGN: This prospective case-comparison study investigated isometric and isokinetic reciprocal trunk flexion and extension strength at angular velocities in 38 unihemispheric stroke patients and 40 healthy volunteers. The Berg balance scale was used to assess balance and stability, and the FIM instrument was used to evaluate functional disability in the patient group. Patients were evaluated as soon as they were able to stand long enough for testing. RESULTS: Peak torque values for trunk flexion and extension were lower in the stroke patients than in the controls. The differences were significant for trunk flexion and for trunk extension. In both groups, peak torque values for trunk flexors were greater than peak torque values for trunk extensors. There was a significant positive correlation between trunk muscle strength and Berg balance scale score at discharge. Trunk muscle strength was not correlated with FIM total score or FIM motor score, but the locomotion-transfers FIM subscore at discharge was positively correlated with trunk muscle torque values, except for isometric extension. CONCLUSION: The findings indicate trunk flexion and extension muscle weakness in unihemispheric stroke patients, which can interfere with balance, stability, and functional disability.     

Évaluation isocinétique des muscles fléchisseurs et extenseurs du genou chez de jeunes footballeurs

Objective

To assess the knee muscles power using isokinetic in a population of young soccer players. To investigate the relationships between isokinetic peak torque and each player's position in the playground.

Population and methods

Thirty-eight young soccer players (mean age 14.57 years old with extremes ranging from 13 to 17 years old) underwent an isokinetic assessment on both knees on an isokinetic dynamometer Cybex-NORM™ on three angular velocities: 60 °/s, 180 °/s and 240 °/s concentric mode. The peak torque, the peak torque on the weight and the ratio of hamstring/quadriceps were noted. These athletes were divided into three groups: strikers (16), defenders (16), and goalkeepers (6).

Results

Hamstring/quadriceps ratio was at low speed 60 °/s between 72 and 74%, at medium speed (180 °/s) between 78 and 80%, and high speed (240 °/s) between 85 and 90%, the peak torque by extensor muscles weight was around 2.6 N m/kg. Overall, there was no significant difference between the three groups of players; there were no significant difference between the dominant side and the non dominant side.

Conclusion

There was no significant difference of the isokinetic peak torque between the players, no difference between agonist and antagonist muscles activity in isometric knee strength and no difference between the dominant side and the non dominant side. The isokinetic is a method for the assessment of the force and preventing muscle injuries of the knee.     

Isometric and isokinetic knee extension and flexion torque in men and women aged 20-70

An investigation was made of the influence of age and sex on peak muscle torque in knee extension and flexion during maximal isokinetic and isometric contraction. The study was performed on both legs of 139 clinically healthy men and 141 clinically healthy women aged 20, 30, 40, 50, 60 or 70 years. Maximum knee extension and flexion muscle torque (Newtonmetre, Nm) was measured isokinetically at various angles of velocity (12, 90 and 150 degrees/s) and isometrically under standardized conditions (Cybex II). No significant differences were found between the right and the left leg in the whole material. Muscle torque was higher in men than in women in all age groups (p less than 0.001). Both isokinetic and isometric torque decreased with age in both sexes. Isokinetic torque decreased significantly (p less than 0.05) between 20 and 30 years of age in men and between 40 and 50 years of age in women (at all velocities studied; p less than 0.05). A significant decrease (p less than 0.05) was found between the ages of 60 and 70 years in both sexes. Maximum isometric torque showed a significant decrease (p less than 0.05) between 60 and 70 years in men and women. There were no significant differences in isokinetic or isometric torque between moderately active and inactive men or women. Significant correlations were found between muscle torque and body weight, height and body surface area.