Dynamic muscle strength training in stroke patients: Effects on knee extension torque, electromyographic activity, and motor function

Experimental Gerontology

et al. 2010

118

125

Overall reductions in muscle strength typically accompany the aging process. However, older adults show a relatively preserved capacity of producing eccentric strength. The preservation of eccentric strength in older adults is a well-established phenomenon, occurring indiscriminately across different muscle groups, independent of age-related architectural changes in muscle structure and velocity of movement.The mechanisms for the preservation of eccentric strength appear to be mechanical and cellular in origin and include both passive and active elements regulating muscle stiffness. The age-related accumulation of non-contractile material in the muscle-tendon unit increases passive stiffness, which might offer mechanical advantage during eccentric contractions. In addition, the preserved muscle tension and increased instantaneous stiffness of old muscle fibers during stretch increase active stiffness, which might enhance eccentric strength.The fact that the preservation of eccentric strength is present in people with chronic conditions when compared to age-matched healthy controls indicates that the aging process per se does not exclusively mediate the preservation of eccentric strength. Physical inactivity, which is common in elderly and people with chronic conditions, is a potential factor regulating the preservation of eccentric strength.When compared to concentric strength, the magnitude of the preservation of eccentric strength in older adults ranges from 2% to 48% with a mean value from all studies of 21.6%. This functional reserve of eccentric strength might be clinically relevant, especially to initiate resistance training and rehabilitation programs in individuals with low levels of strength.

Section: Introductionmentioning

confidence: 99%

Preservation of eccentric strength in older adults: Evidence, mechanisms and implications for training and rehabilitation

Roig

Experimental Gerontology

et al. 2010

118

125

“…20 These correlational studies have fueled the hypothesis that interventions aimed at increasing muscle strength will result in improvements in functional performance for these individuals. Recent studies have demonstrated that lower extremity strengthening programs with individuals with chronic stroke can have positive effects on gait performance, 10,12,13 stair climbing ability, 13 rising from a chair, 21 and quality of life. 13 Muscle performance has been commonly measured by isokinetic dynamometers as their instrumentation accuracy has been established 22,23 .…”

Section: Introductionmentioning

confidence: 99%

Reliability of lower extremity strength measures in persons with chronic stroke

Kim

Archives of Physical Medicine and Rehabilitation

2002

Objective-To determine the reliability of isokinetic concentric strength measures of both the hemiparetic and non-involved limbs for flexion and extension motions of the hip, knee, and ankle joints in individuals who have had a stroke.Design-Test-retest, repeated-measures intraobserver reliability design. Setting-Tertiary rehabilitation center.Participants-20 community-dwelling individuals who have had a stroke, with motor deficits ranging from 3 to 6 on the Chedoke-McMaster Stroke Assessment; volunteer sample. Interventions-Not applicable.Main Outcome Measures-Peak torque and average torque (ie, mean over the range of motion tested) from an ensemble-averaged (three trials) torque-angle curve during isokinetic concentric extension and flexion movements of the ankle, knee, and hip.Results-Although peak and average torque were significantly less for the hemiparetic limb compared with the non-involved limb, the intraclass correlation coefficients (ICCs) between the two test sessions were high (0.95-0.99 for peak torque, 0.88-0.98 for average torque) for both limbs for all 3 joints. However, there was a learning effect, as observed by the slightly greater values attained from the second test session.Conclusions-Peak and average isokinetic torque can be used to assess reliably lower extremity strength in persons with chronic stroke. Practice sessions may be required before the actual test to reduce the effect of learning.

“…11,19 Several studies have suggested that lower extremity strength training can improve functional performance in addition to self-perceived health in individuals with stroke. 11,[20][21][22][23][24][25] Many of these studies have combined strengthening with other types of training (e.g., balance, endurance); only a few have investigated the functional gains achieved by strength training alone. Six weeks of maximal isokinetic strengthening of the knee musculature has been found to significantly improve walking speed in persons with stroke.…”

Section: Introductionmentioning

confidence: 99%

“…Six weeks of maximal isokinetic strengthening of the knee musculature has been found to significantly improve walking speed in persons with stroke. 11,22 Furthermore, a 9-week bilateral isokinetic program using the Kinetron, 25 as well as an 8-week isokinetic strengthening program of isolated flexor and extensor muscle groups of the paretic lower extremity, 23 have also been reported to improve walking speed.…”

Section: Introductionmentioning

confidence: 99%

Effects of isokinetic strength training on walking in persons with stroke: A double-blind controlled pilot study

Kim

Journal of Stroke and Cerebrovascular Diseases

et al. 2001

127

Objectives-The goal most often stated by persons with stroke is improved walking function. The purpose of this study was to determine the effects of isokinetic strength training on walking performance, muscle strength, and health-related quality of life in survivors of chronic stroke.Methods-Twenty participants (age, 61.2 ± 8.4 years) with chronic stroke were randomized into 2 groups. The experimental group undertook maximal concentric isokinetic strength training, whereas the control group received passive range of motion of the paretic lower extremity 3 times a week for 6 weeks. The Kin-Com Isokinetic Dynamometer (Chattanooga Group Inc., TN) was used for both the strengthening and passive range of motion exercises. The Mann-Whitney U test was used to compare the changes in scores (postintervention minus baseline) between the control and experimental groups for a composite lower extremity strength score, walking speed (levelwalking and stair-walking) and health-related quality of life measure (36-Item Short Form Health Survey ).Results-Both the experimental and control groups increased their strength and walking speed postintervention; however, there were no differences in the changes in walking speed between the groups. There was a trend (P = .06) toward greater strength improvement in the experimental group compared with the control group. No changes in SF-36 scores were found in either group.Conclusions-Intervention aimed at increasing strength did not result in improvements in walking. The results of this study stress the importance of controlled clinical trials in determining the effect of specific treatment approaches. Strength training in conjunction with other task-related training may be indicated.