title: Muscle strength of trunk flexion-extension in post-stroke hemiplegic patients. Reliability of isokinetic normalized peak torque assessments for knee muscles in post-stroke hemiparesis. Trunk rotatory muscle performance in post-stroke hemiplegic patients. Reliability of Dynamic Muscle Performance in the Hemiparetic Upper Limb Reliability of concentric and eccentric torque during isokinetic knee extension in post-stroke hemiparesis.
abstract: This study was undertaken to determine muscle strength of trunk flexion-extension in hemiplegic patients after stroke compared with that of normal controls . The design consisted of a nonr and omized control trial in a secondary care setting ( a rehabilitation unit at a hospital facility ) . The subjects included 25 post-stroke male hemiplegic patients and 25 male healthy controls . The maximal peak torques of trunk flexion-extension  at angular velocities of 0 degrees ( isometric contraction ) , 60 degrees , 120 degrees , and 150 degrees/s were measured by using an isokinetic dynamometer ( Cybex Trunk Extension-Flexion Unit , Cybex , Ronkonkoma , NY ) . Peak torque of trunk flexion and extension in hemiplegic patients was significantly smaller than that of healthy controls ( P < 0.05 ) , except isometric trunk flexion ( P > 0.05 ) . The weakness of trunk flexion-extension muscles in hemiplegic patients might be accounted for by the bilateral innervation from the motor cortex , the insufficient use of high threshold motor units , and disuse atrophy The purpose of this study was to establish test-retest reliability of measurement procedures for quantifying isokinetic concentric peak torque ( PT ) at the knee using normalization methods post-stroke . A second aim was to estimate the change required to show clinical ly significant improvements in knee muscles strength .  The isokinetic normalized PT ( NPT ) values for the knee extensors and flexors were measured in each participant at two different angular velocities during two sessions 1 day apart . Thirty participants with mild to moderate hemiparesis after stroke who were able to walk were tested . The normalized PT measures for the knee muscles of the affected lower extremity were highly reliable ( intraclass correlation coefficients ranged from 0.85 to 0.98 ; p<0.05 ) . Size of relative changes ( the percent smallest real difference , SRD% ) for extensors NPT ( ranged from 22.35 % to 25.68 % ) were lower than flexors NPT ( ranged from 74.01 % to 76.31 % ) , indicating that the affected isokinetic knee flexors had more r and om variation than the knee extensors . This study supports the use of isokinetic dynamometers for the assessment of knee muscle strength in participants with chronic mild to moderate post-stroke hemiparesis and to measure clinical improvements . Established measurement error and smallest real differences in normalized PT will aid interpretation of real changes in muscle strength in this clinical population This study was undertaken to determine whether the direction of trunk rotation would have any effect on trunk muscle performance of post-stroke hemiplegic patients . The design consisted of a nonr and omized control trial in a setting of secondary care ( rehabilitation unit at hospital facility ) . The subjects included 65 hemiplegic patients ( 50 males ) and age-matched 80 healthy controls ( 38 females ) .  Isokinetic trunk rotatory muscle performance at angular velocities of 60 , 120 , and 150 degrees per second was measured by using an isokinetic dynamometer ( Cybex Torso Rotation Unit ) . There were no significant differences in the peak torque and best work between the right and left directions of the trunk rotation in the hemiplegic patients or in healthy controls , regardless of the gender of the subjects ( paired t test , P > 0.05 ) . The muscle performance of the hemiplegic patients was significantly lower than that of the controls for both genders ( t test , P < 0.05 ) . In the hemiplegic patients , the direction of trunk rotation does not affect the trunk rotatory muscle performance , although the performance itself was slightly decreased We established reliability of upper-limb muscle performance in adults with post-stroke hemiparesis . Ten adults with post-stroke hemiparesis ( 51.5 ± 34 . 5 months ) performed isokinetic concentric shoulder flexion , elbow flexion , and extension at 3 criterion speeds ( 30 ° /s , 75 ° /s , and 120 ° /s ) on 3 separate occasions ( Days 1,7 , and 49 ) . As several participants were unable to reach criterion speeds , actual speed and power were also analyzed . Relative reliability ( intr-aclass correlation coefficient-ICC ) was excellent for torque and power ( 0.82 to 0.98 ) but less consistent for speed ( 0.63 to 0.99 ) . Absolute reliability ( st and ard error of measurement-%SEM ) ranged between 0 % to 34 % . No systematic errors were observed across sessions . Smallest real differences ( SRD ) ranged between 4–11Nm for torque and 3–24W for power . Shoulder flexion , elbow flexion , and elbow extension torque , speed , and power can be measured reliably following stroke . Given that many of these individuals demonstrate inability to generate torque at preselected speeds , power may be a more valid indicator of muscle performance BACKGROUND Emerging evidence on the velocity-dependent nature of force impairment in post-stroke hemiparesis has emphasized the complexity of strength and motor performance assessment s in this clinical population . The need to establish reliability and responsiveness of muscle performance measures across a broad range of concentric and eccentric movement speeds is therefore clear , as these metrics will provide benchmarks both for making clinical inference and evaluating meaningful clinical change following interventions . METHODS Isokinetic knee extensor strength was tested at 14 angular velocities in 17 adults with chronic post-stroke hemiparesis ( > 18 months ) , and 13 non-disabled controls . Identical tests were conducted on two occasions separated by two days . Test-retest reliability of maximal isokinetic torque was evaluated using intraclass correlation . Absolute reliability was assessed using st and ard error of measurement from which smallest real differences were derived . FINDINGS Overall , intraclass correlation coefficients were excellent for both hemiparetic ( 0.891 ) and control ( 0.937 ) groups . Intraclass correlation coefficients for each criterion speed were also high for both groups ( > 0.86 ) . Measurement error relative to the mean torque varied between 14.1 % and 26.3 % for hemiparetic subjects and 6.0 - 18.1 % for controls . The smallest real difference relative to mean torque was 39.0 - 72.7 % and 16.6 - 50.2 % for hemiparetic and control subjects , respectively . INTERPRETATION Isokinetic knee extension torque can be measured reliably in persons with chronic post-stroke hemiparesis and in non-disabled controls across a full functional range of concentric and eccentric speeds . Established measurement error and smallest real differences will aid interpretation of longitudinal observations of muscle performance in this clinical population
target: Conclusion :  Objective muscle strength assessment  can be reliably used in lower and upper extremities in post-stroke patients with chronic hemiparesis
background: Background : Muscle weakness is the main cause of motor impairment among stroke survivors and is associated with reduced peak muscle torque .
  Objective : To systematic ally investigate and organize the evidence of the reliability of muscle strength evaluation measures in post-stroke survivors with chronic hemiparesis .