Key characteristics of walking correlate with bone density in individuals with chronic stroke.

Several recent studies of ambulatory stroke survivors have shown decreased bone mineral density (BMD) in the lower limbs and an elevated risk of hip fracture. Because bone mass is linked to skeletal loading, weight-bearing activities of daily living such as walking are considered critically important for maintenance of femoral BMD in ambulatory individuals. Little is known about the relationships between walking characteristics, skeletal loading, and bone maintenance in individuals who have experienced a stroke. This study determined whether certain gait-related parameters correlate with proximal femoral BMD in ambulatory individuals with poststroke walking deficits. We analyzed data from 33 individuals with chronic stroke and found that a recently introduced metric, the Bone Density Index, which incorporates body weight, number of steps per day, and ground reaction force magnitude, predicted proximal femoral BMD better than other commonly measured demographic and gait-related parameters that we examined.

Effects of a simple functional electric system and/or a hinged ankle-foot orthosis on walking in persons with incomplete spinal cord injury.

OBJECTIVES: To compare the effect of functional electric stimulation (FES) with that of a hinged ankle-foot orthosis (AFO) for assisting foot clearance, gait speed, and endurance and to determine whether there is added benefit in using FES in conjunction with the hinged AFO in persons with incomplete spinal cord injury (SCI). DESIGN: Within-subject comparison of walking under 4 conditions: AFO, FES, AFO and FES, and no orthosis. A plastic hinged AFO was used for all AFO conditions. SETTING: Tertiary rehabilitation center. PARTICIPANTS: Nineteen subjects with incomplete SCI. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The self-selected gait speed, 6-minute walk distance, and foot clearance values were compared between conditions. RESULTS: Gait speed increased with FES ( P <.05) and with the AFO ( P =.06). Six-minute walk distance also increased with the AFO ( P <.05). No difference was found between the 2 forms of orthoses in either gait speed or endurance. The greatest increase in gait speed and endurance from the no-orthosis condition occurred with the combined AFO and FES condition. Foot clearance improved with FES but not with AFO. Subjects whose gait speed increased with FES had weaker hip flexors, knee flexors, and ankle dorsiflexors than those who did not benefit from FES. CONCLUSIONS: Both FES and the hinged AFO promote walking and FES is only superior to the AFO in increasing foot-clearance values. The hinged AFO and FES together may offer advantages over either device alone.

Magnitude and pattern of 3D kinematic and kinetic gait profiles in persons with stroke: relationship to walking speed.

The purpose of this study was to identify 3D kinematic and kinetic gait profiles in individuals with chronic stroke and to determine whether the magnitude or pattern (shape and direction of curve) of these profiles relate to gait performance (as measured by self-selected gait speed). More than one type of kinematic and kinetic pattern was identified in all three planes in 20 individuals with stroke (age: 61.2+/-8.4 years). Persons in the "fast" speed group did not necessarily exhibit the gait patterns closest to the ones reported for healthy adults. For example, in the frontal plane, a variation from the typical pattern (i.e., a hip abductor pattern in swing) was more common among the "fast" group. Correlations revealed that in addition to the sagittal profiles, the magnitudes of the frontal and transverse profiles are also related to speed, particularly the frontal hip powers. The results support the importance of hip abductors, in addition to the sagittal plane muscle groups, for both the paretic and non-paretic limbs. Furthermore, profiles which resemble gait patterns of neurologically healthy adults do not necessarily result in the faster gait speeds for individuals with chronic stroke.

A community-based group exercise program for persons with chronic stroke.

PURPOSE: The purpose of this study was to evaluate the physical and psychosocial effects of an 8-wk community-based functional exercise program in a group of individuals with chronic stroke. METHODS: Twenty-five subjects (mean age 63 yr) participated in a repeated measures design that evaluated the subjects with two baseline assessments 1 month apart, one postintervention assessment, and one retention assessment 1 month postintervention. Physical outcome measures assessed were the Berg Balance Test, 12-Minute Walk Test distance, gait speed, and stair climbing speed. Psychosocial measures assessed were the Reintegration to Normal Living Index (RNL) and Canadian Occupational Performance Measure (COPM). The 8-wk training consisted of a 60-min, 3 x wk-1 group program that focused on balance, mobility, functional strength, and functional capacity. The program was designed to be accessible by reducing the need for costly one-on-one supervision, specialized settings, and expensive equipment. RESULTS: Improvements from the exercise program were found for all physical measures and these effects were retained 1-month postintervention. Subjects with lower function improved the most relative to their initial physical status. Significant effects were found for the COPM, but not the RNL Index; however, subjects with lower RNL improved the most relative to their initial RNL Score. CONCLUSION: A short-term community-based exercise program can improve and retain mobility, functional capacity, and balance and result in a demonstrable impact upon the performance of activities and abilities that were considered meaningful to the subjects. Implementation of such community-based programs has potential for improving activity tolerance and reducing the risk for secondary complications common to stroke (e.g., falls resulting in fractures and cardiac events).

Symmetry in vertical ground reaction force is accompanied by symmetry in temporal but not distance variables of gait in persons with stroke.

The purpose of this study was to (1) determine whether symmetry in temporal-distance (T-D) measures is accompanied by symmetry in kinetic measures during self-paced gait and (2) evaluate the effect of symmetry on gait speed in individuals with chronic stroke. A symmetry index was calculated for stance time, swing time, step length and vertical ground reaction force (GRF) for 28 individuals with stroke (age: 62.5+/-8.2 years). Spearman correlation revealed that (a) gait speed was correlated with the symmetry of temporal measures and GRF and (b) symmetry in GRF was correlated with symmetry in temporal but not distance measures of gait (P<0.05). The results provide support for promoting temporal and kinetic symmetry in the gait of persons with stroke.

The relationship of lower-extremity muscle torque to locomotor performance in people with stroke.

BACKGROUND AND PURPOSE: Improved walking is a common goal after stroke. The purpose of this study was to examine the relationship between the torque generated by the muscles of both lower extremities and 2 locomotor tasks: gait on level surfaces and stair climbing in people who had strokes. SUBJECTS: Twenty community-dwelling individuals (mean age=61.2 years, SD=8.4, range=52-82) who had strokes and who were able to walk independently participated in the study. The mean time since stroke was 4.0 years (SD=2.6, range=1.5-10.0). METHODS: Pearson correlations and multiple regression were used to measure the relationship between concentric isokinetic torque of the flexor and extensor muscles of the hip, knee, and ankle bilaterally and locomotor performance (gait on level surfaces and stair-climbing speed). RESULTS: The isokinetic torques of the paretic ankle plantar flexors, hip flexors, and knee flexors had moderate to high correlations (r=.5-.8) with gait and stair-climbing speeds. Muscle force could explain 66% to 72% of the variability in gait and stair-climbing speeds. Correlations for the nonparetic side were as high as or higher than those for the paretic side for some muscle groups. DISCUSSION AND CONCLUSION: Muscle performance measurements of both limbs should be included in the evaluation of locomotion and treatment of people following a stroke.

Reliability of lower extremity strength measures in persons with chronic stroke.

OBJECTIVE: To determine the reliability of isokinetic concentric strength measures of both the hemiparetic and noninvolved 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: Twenty 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 (3 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 noninvolved limb, the intraclass correlation coefficients (ICCs) between the 2 test sessions were high (.95-.99 for peak torque,.88-.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.

Functional walk tests in individuals with stroke: relation to perceived exertion and myocardial exertion.

BACKGROUND AND PURPOSE: Functional walk tests such as the 6- and 12-Minute Walk Test (ie, 6MWT and 12MWT, respectively) are submaximal measures used to determine functional capacity in individuals with compromised ability. The purpose of this study was to determine the relationship between these walk tests and measures of exertion (perceived and myocardial), in addition to impairment in individuals with stroke. The relationship among the 6MWT, 12MWT, and the more traditionally assessed measure of self-paced gait speed (generally assessed over a short distance, eg, 10 m) was also evaluated. METHODS: Twenty-five community-dwelling individuals with stroke were evaluated for the following: 12MWT distance, 6MWT distance, self-paced gait speed over 8 m, plantarflexion strength, Berg Balance Scale, Ashworth Scale of Spasticity, and Chedoke-McMaster Stroke Assessment. Heart rate (HR), rate-pressure product (RPP), and perceived exertion were assessed during the functional walk tests. Correlational analysis quantified the relationship between gait, impairment measures, and physiological responses during the functional walk tests. RESULTS: HR reached a steady state after 6 minutes and reflected a moderate exercise intensity of 63% of age-predicted maximum HR. The 6MWT, 12MWT, and self-paced gait speed were all highly correlated with one another (r>0.90) and were all also related to the severity of impairments. The functional walk distances did not relate either to perceived exertion or actual exertion (increase in the myocardial oxygen demand as measured by RPP). CONCLUSIONS: Stroke-specific impairments are the major limitations to the distance walked in individuals with stroke. If the functional walk test is used to assess performance of an individual over time (eg, in response to an intervention), we recommend that both exertion (eg, increase in RPP or HR) and distance be measured.