Biomedical subjects

Andrew S Dawson

Publications and source records attributed to Andrew S Dawson.

9 recordsLinked to original sources

PubMed2006

The use of aerobic exercise training in improving aerobic capacity in individuals with stroke: a meta-analysis.

OBJECTIVE: To determine whether aerobic exercise improves aerobic capacity in individuals with stroke. DESIGN: A systematic review of randomized controlled trials. DATABASES SEARCHED: MEDLINE, CINAHL, EMBASE, Cochrane Database of Systematic Reviews and Physiotherapy Evidence Database were searched. INCLUSION CRITERIA: Design: randomized controlled trials (RCTs). PARTICIPANTS: individuals with stroke. INTERVENTIONS: aerobic exercise training aimed at improving aerobic capacity. OUTCOMES PRIMARY OUTCOMES: aerobic capacity (peak oxygen consumption (VO2), peak workload). SECONDARY OUTCOMES: walking velocity, walking endurance. DATA ANALYSIS: The methodological quality was assessed by the PEDro scale. Meta-analyses were performed for all primary and secondary outcomes. RESULTS: Nine articles (seven RCTs) were identified. The exercise intensity ranged from 50% to 80% heart rate reserve. Exercise duration was 20-40 min for 3-5 days a week. The total number of subjects included in the studies was 480. All studies reported positive effects on aerobic capacity, regardless of the stage of stroke recovery. Meta-analysis revealed a significant homogeneous standardized effect size (SES) in favour of aerobic exercise to improve peak VO2 (SES 0.42; 95% confidence interval (CI) 0.15-0.69; P=0.001) and peak workload (SES 0.50; 95% CI 0.26-0.73; P<0.001). There was also a significant homogeneous SES in favour of aerobic training to improve walking velocity (SES 0.26; 95% CI 0.05-0.48; P= 0.008) and walking endurance (SES 0.30; 95% CI 0.06-0.55; P= 0.008). CONCLUSIONS: There is good evidence that aerobic exercise is beneficial for improving aerobic capacity in people with mild and moderate stroke. Aerobic exercise should be an important component of stroke rehabilitation.

Adult↗

PubMed2005

Reduced hip bone mineral density is related to physical fitness and leg lean mass in ambulatory individuals with chronic stroke.

Following a stroke, the reduced level of physical activity and functional use of the paretic leg may lead to bone loss and muscle atrophy. These factors and the high incidence of falls may contribute to hip fractures in the stroke population. This study was the first to examine total proximal femur bone mineral content (BMC) and bone mineral density (BMD) and their relationship to stroke-specific impairments in ambulatory individuals with chronic stroke (onset >1 year). We utilized dual-energy X-ray absorptiometry (DXA) to acquire proximal femur and total body scans on 58 (23 women) community-dwelling individuals with chronic stroke. We reported total proximal femur BMC (g) and BMD (g/cm2) derived from the proximal femur scans, and lean mass (g) and fat mass (g) for each leg derived from the total body scans. Each subject was evaluated for ambulatory capacity (Six-Minute Walk Test), knee extension strength (hand-held dynamometry), physical fitness [maximal oxygen uptake (VO2max)] and spasticity (Modified Ashworth Scale). Results showed that the paretic leg had significantly lower proximal femur BMD, lean mass and percent lean mass, but higher fat mass than the non-paretic leg for both men and women. Proximal femur BMD of the paretic leg was significantly related to ambulatory capacity (r=0.33, P=0.011), muscle strength (r=0.39, P=0.002), physical fitness (r=0.57, P<0.001), but not related to spasticity (r=-0.23, P=0.080). Multiple regression analysis showed that lean mass in the paretic leg was a major predictor (r2=0.371, P<0.001) of the paretic proximal femur BMD. VO2max was a significant predictor of both paretic proximal femur BMD (r2=0.325, P<0.001) and lean mass in the paretic leg (r2=0.700, P<0.001). Further study is required to determine whether increasing physical fitness and lean mass are important to improve hip bone health in chronic stroke.

Absorptiometry, Photon↗

PubMed2005

Exercise leads to faster postural reflexes, improved balance and mobility, and fewer falls in older persons with chronic stroke.

OBJECTIVES: To determine the effect of two different community-based group exercise programs on functional balance, mobility, postural reflexes, and falls in older adults with chronic stroke. DESIGN: A randomized, clinical trial. SETTING: Community center. PARTICIPANTS: Sixty-one community-dwelling older adults with chronic stroke. INTERVENTION: Participants were randomly assigned to an agility (n=30) or stretching/weight-shifting (n=31) exercise group. Both groups exercised three times a week for 10 weeks. MEASUREMENTS: Participants were assessed before, immediately after, and 1 month after the intervention for Berg Balance, Timed Up and Go, step reaction time, Activities-specific Balance Confidence, and Nottingham Health Profile. Testing of standing postural reflexes and induced falls evoked by a translating platform was also performed. In addition, falls in the community were tracked for 1 year from the start of the interventions. RESULTS: Although exercise led to improvements in all clinical outcome measures for both groups, the agility group demonstrated greater improvement in step reaction time and paretic rectus femoris postural reflex onset latency than the stretching/weight-shifting group. In addition, the agility group experienced fewer induced falls on the platform. CONCLUSION: Group exercise programs that include agility or stretching/weight shifting exercises improve postural reflexes, functional balance, and mobility and may lead to a reduction of falls in older adults with stroke.

Accidental Falls↗

PubMed2005

A community-based fitness and mobility exercise program for older adults with chronic stroke: a randomized, controlled trial.

OBJECTIVES: To examine the effects of a community-based group exercise program for older individuals with chronic stroke. DESIGN: Prospective, single-blind, randomized, controlled intervention trial. SETTING: Intervention was community-based. Data collection was performed in a research laboratory located in a rehabilitation hospital. PARTICIPANTS: Sixty-three older individuals (aged > or = 50) with chronic stroke (poststroke duration > or = 1 year) who were living in the community. INTERVENTION: Participants were randomized into intervention group (n=32) or control group (n=31). The intervention group underwent a fitness and mobility exercise (FAME) program designed to improve cardiorespiratory fitness, mobility, leg muscle strength, balance, and hip bone mineral density (BMD) (1-hour sessions, three sessions/week, for 19 weeks). The control group underwent a seated upper extremity program. MEASUREMENTS: Cardiorespiratory fitness (maximal oxygen consumption), mobility (6-minute walk test), leg muscle strength (isometric knee extension), balance (Berg Balance Scale), activity and participation (Physical Activity Scale for Individuals with Physical Disabilities), and femoral neck BMD (using dual-energy x-ray absorptiometry). RESULTS: The intervention group had significantly more gains in cardiorespiratory fitness, mobility, and paretic leg muscle strength than controls. Femoral neck BMD of the paretic leg was maintained in the intervention group, whereas a significant decline of the same occurred in controls. There was no significant time-by-group interaction for balance, activity and participation, nonparetic leg muscle strength, or nonparetic femoral neck BMD. CONCLUSION: The FAME program is feasible and beneficial for improving some of the secondary complications resulting from physical inactivity in older adults living with stroke. It may serve as a good model of a community-based fitness program for preventing secondary diseases in older adults living with chronic conditions.

Activities of Daily Living↗

PubMed2005

Relationship between ambulatory capacity and cardiorespiratory fitness in chronic stroke: influence of stroke-specific impairments.

STUDY OBJECTIVES: To identify the following in individuals with chronic stroke: (1) the relationship between the maximal oxygen consumption (Vo(2)max) during cycle ergometry and the distance covered in the 6-min walk test (6MWT), and (2) the stroke-specific impairments that are important determinants for the 6MWT distance. DESIGN: Cross-sectional study using a convenience sample. SETTING: Exercise testing laboratory in a tertiary rehabilitation center. PARTICIPANTS: Sixty-three older adults (mean age +/- SD, 65.3 +/- 8.7 years) with an average poststroke interval of 5.5 +/- 4.9 years. INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: Each subject underwent a maximal cycle ergometer test and a 6MWT. Oxygen consumption (Vo(2)) was measured during both tests. Subjects were also evaluated for Berg balance scale, modified Ashworth scale of spasticity, isometric knee extension strength, and percentage of body fat. RESULTS: The 6MWT distance had a low correlation with the Vo(2)max (r = 0.402). Balance, knee extension strength, and spasticity were all significant determinants for the 6MWT distance, with balance being the major contributor for the 6MWT distance, accounting for 66.5% of its variance. CONCLUSIONS: Factors other than the cardiorespiratory status considerably influenced the ambulatory capacity as measured by the 6MWT. The 6MWT distance alone should not be used to indicate cardiorespiratory fitness in individuals with chronic stroke.

Activities of Daily Living↗

PubMed2004

Water-based exercise for cardiovascular fitness in people with chronic stroke: a randomized controlled trial.

OBJECTIVE: To evaluate the effect of an 8-week, water-based exercise program (experimental group) with that of an upper-extremity function program (control group) to increase cardiovascular fitness within a community setting for people with stroke. DESIGN: Single-blind randomized controlled trial. SETTING: Public community center. PARTICIPANTS: A volunteer sample of 12 community-dwelling people with stroke with mild to moderate residual motor deficits. INTERVENTION: Study subjects participated in group exercise programs for 1 hour, 3 times a week for 8 weeks. The experimental group exercised in chest-deep water at targeted heart rates. The control group performed arm and hand exercises while sitting. Main outcome measures The primary outcome measure was cardiovascular fitness (V(O2)max). Secondary measures were maximal workload, muscle strength, gait speed, and the Berg Balance Scale score. RESULTS: The experimental group attained significant improvements over the control group in cardiovascular fitness, maximal workload, gait speed, and paretic lower-extremity muscle strength. The relatively short program (8 wk) of water-based exercise resulted in a 22% improvement in cardiovascular fitness in a small group of people with stroke who had relatively high function. CONCLUSIONS: A water-based exercise program undertaken as a group program may be an effective way to promote fitness in people with stroke.

Aged↗

PubMed2004

Submaximal exercise in persons with stroke: test-retest reliability and concurrent validity with maximal oxygen consumption.

OBJECTIVE: To establish the test-retest reliability and concurrent validity with maximum oxygen consumption (VO2max) for 3 submaximal exercise tests in persons with chronic stroke: (1) submaximal treadmill test, (2) submaximal cycle ergometer test, and (3) 6-minute walk test (6MWT). DESIGN: Prospective study using a convenience sample. SETTING: Free-standing tertiary rehabilitation center. PARTICIPANTS: A volunteer sample of 12 community-dwelling individuals who had a stroke with moderate motor deficits. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Heart rate, blood pressure, and oxygen consumption (VO2) were assessed during the exercise tests. RESULTS: Test-retest reliability was good to excellent for the exercise tests (maximal and submaximal tests). VO2 for all submaximal measures related to VO2max (r range, .66-.80). Neither the 6MWT distance, self-selected gait speed, nor hemodynamic measures related to VO2max. CONCLUSION: The VO2 measures of the submaximal exercise tests had excellent reliability and good concurrent validity with VO2max. Submaximal exercise tests may be a method by which to monitor the effects of interventions after a screening test (eg, symptom-limited graded exercise test, dobutamine stress echocardiograph).

Aged↗

PubMed2003

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).

Activities of Daily Living↗

PubMed2002

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.

Aged↗