Reliability of concentric and eccentric torque during isokinetic knee extension in post-stroke hemiparesis. Muscle Weakness and Cocontraction in Upper Limb Hemiparesis: Relationship to Motor Impairment and Physical Disability Reliability of isokinetic normalized peak torque assessments for knee muscles in post-stroke hemiparesis. Muscle strengthening and physical conditioning to reduce impairment and disability in chronic stroke survivors. Comparison of Bilateral and Unilateral Training for Upper Extremity Hemiparesis in Stroke
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 The purpose of this article is to describe the relationship between poststroke upper limb muscle weakness and cocontraction , and clinical measures of upper limb motor impairment and physical disability .  Electromyographic ( EMG ) activity of the  paretic and nonparetic wrist flexors and extensors of 26 chronic stroke survivors were recorded during isometric wrist flexion and extension . The root mean square ( RMS ) of the EMG signal was used as a measure of strength of contraction . A ratio of RMS of antagonist and agonist muscles was used as a measure of cocontraction . Upper limb motor impairment and physical disability were assessed with the Fugl-Meyer motor assessment ( FMA ) and the  arm motor ability test ( AMAT ) , respectively . The strength of muscle contraction was significantly stronger in the nonparetic limb ( P < 0.001 ) . The degree of cocontraction was significantly greater in the paretic limb ( P < 0.001 ) . The strength of muscle contraction in the paretic limb correlated significantly with FMA ( r = 0.62 to 0.87,P ≤ 0.001 ) and AMAT ( r = 0.66 to 0.80 , P ≤ 0.001 ) scores . Similarly , the degree of cocontraction correlated significantly with FMA ( r = -0.70 to -0.64 , P ≤ 0.001 ) and AMAT ( r = -0.72 to -0.62 , P ≤ 0.001 ) scores . Muscle weakness and degree of cocontraction correlate significantly with motor impairment and physical disability in upper limb hemiplegia . This relationship may provide insights toward development of specific interventions . However , additional studies are needed to demonstrate a cause and effect relationship 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 OBJECTIVE To evaluate the impact of a program of muscle strengthening and physical conditioning on  impairment and disability in chronic stroke subjects . DESIGN A r and omized pretest and posttest control group , followed by a single-group pretest and posttest design . SUBJECTS Thirteen community-dwelling stroke survivors of at least 9 months . INTERVENTION A 10-week ( 3 days/week ) program consisting of a warm-up , aerobic exercises , lower extremity muscle strengthening , and a cool-down . MAIN OUTCOME MEASURES Peak isokinetic torque of the major muscle groups of the affected lower limb , quadriceps and ankle plantarflexor spasticity , gait speed , rate of stair climbing , the Human Activity Profile ( HAP ) , and the Nottingham Health Profile ( NHP ) were recorded twice for the treatment group and three times for the control group . RESULTS Significant improvements were found for all the selected outcome measures ( HAP , NHP , and gait speed ) for the treatment group ( p < .001 ) . In terms of overall training effects , the 13 subjects demonstrated increases in strength of the affected major muscle groups , in HAP and NHP profiles , and in gait speed and rate of stair climbing without concomitant increases in either quadriceps or ankle plantarflexor spasticity . CONCLUSIONS The 10-week combined program of muscle strengthening and physical conditioning result ed in gains in all measures of impairment and disability . These gains were not associated with measurable changes of spasticity in either quadriceps or ankle plantarflexors Background . Upper extremity hemiparesis is the most common poststroke disability . Longitudinal studies have indicated that 30 % to 66 % of stroke survivors do not have full arm function 6 months poststroke . One promising treatment approach is bilateral training . To date , no r and omized , blinded study of efficacy comparing 2 groups ( bilateral training vs unilateral training ) using analogous tasks has been performed in chronic stroke survivors with moderate upper extremity impairment . Objective . To compare the effectiveness of bilateral training with unilateral training for individuals with moderate upper limb hemiparesis . The authors hypothesized that bilateral training would be superior to unilateral training in the proximal extremity but not the distal one . Methods . Twenty-four subjects participated in a r and omized , single-blind training study . Subjects in the bilateral group ( n = 12 ) practice d bilateral symmetrical activities , whereas the unilateral group ( n = 12 ) performed the same activity with the affected arm only . The activities consisted of reaching-based tasks that were both rhythmic and discrete . The Motor Assessment Scale ( MAS ) , Motor Status Scale ( MSS ) , and muscle strength were used as outcome measures . Assessment s were administered at baseline and posttraining by a rater blinded to group assignment . Results . Both groups had significant improvements on the MSS and measures of strength . The bilateral group had significantly greater improvement on the Upper Arm Function scale ( a subscale of the MAS-Upper Limb Items ) . Conclusion . Both bilateral and unilateral training are efficacious for moderately impaired chronic stroke survivors .  Bilateral training may be more advantageous for proximal arm function
Conclusion :  Objective muscle strength assessment  can be reliably used in lower and upper extremities in post-stroke patients with chronic hemiparesis
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 .