Maximal Exercise Test Results in Subacute Stroke

Validity of Cardiopulmonary Exercise Testing for Assessing Aerobic Capacity in Neuromuscular Diseases

OBJECTIVES

To determine the content validity of cardiopulmonary exercise testing (CPET) for assessing peak oxygen uptake (VO2peak) in neuromuscular diseases (NMD).

DESIGN

Baseline assessment of a randomized controlled trial.

SETTING

Academic hospital.

PARTICIPANTS

Eighty-six adults (age: 58.0±13.9 y) with Charcot-Marie-Tooth disease (n=35), postpolio syndrome (n=26), or other NMD (n=25).

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Workload, gas exchange variables, heart rate, and ratings of perceived exertion were measured during CPET on a cycle ergometer, supervised by an experienced trained assessor. Muscle strength of the knee extensors was assessed isometrically with a fixed dynamometer. Criteria for confirming maximal cardiorespiratory effort during CPET were established during 3 consensus meetings of an expert group. The percentage of participants meeting these criteria was assessed to quantify content validity.

RESULTS

The following criteria were established for maximal cardiorespiratory effort: a plateau in oxygen uptake (VO2plateau) as the primary criterion, or 2 of 3 secondary criteria: (1) peak respiratory exchange ratio (RERpeak) ≥1.10 (2), peak heart rate ≥85% of predicted maximal heart rate; and (3) peak rating of perceived exertion (RPEpeak) ≥17 on the 6-20 Borg scale. These criteria were attained by 71 participants (83%). VO2plateau, RERpeak ≥1.10, peak heart rate ≥85%, and RPEpeak ≥17 were attained by 31%, 73%, 69%, and 72% of the participants, respectively. Peak workload, VO2peak, and knee extension muscle strength were significantly higher, and body mass index was lower (all P<.05), in participants with maximal cardiorespiratory effort than other participants.

CONCLUSIONS

Most people with NMD achieved maximal cardiorespiratory effort during CPET. This study provides high quality evidence of sufficient content validity of VO2peak as a maximal aerobic capacity measure. Content validity may be lower in more severely affected people with lower physical fitness.

High-intensity interval training is feasible, credible and clinically effective in the early subacute stroke stage in the low-income country of Benin

High-intensity interval training (HIIT) has been shown to benefit stroke patients when implemented three months post-stroke. This study examined HIIT's feasibility and clinical effectiveness in the early post-stroke stage in Benin. This was a prospective interventional study comprising an HIIT programme executed on a recumbent bike, three times/week, 20-30 min/session for 6 weeks, added to a conventional physiotherapy. The primary outcomes were feasibility, credibility and expectancy assessed with credibility and expectancy questionnaire. A maximal exercise test, 6-min walking test (6MWT), 10-m walking test (10mWT), Berg balance scale (BBS) and five repetitions sit-to-stand test (5 R-STS) were performed before and after the training programme. Ten outpatients, with a median age [P25-P75]: 63.5[56.7-71.2] years; time since stroke: 15.0[9.7-21.0] days, started and completed all training sessions without serious adverse events. High scores were observed on the Credibility subscale at admission (27.0[25.7-27.0]), which remained so after intervention (26.5[25.7-27.0]). Expectancy subscale scores were high at admission (25.5[24.0-27.0]) and post-training (25.5[24.5-27.0]). Peak workload (p < 0.001), BBS (p < 0.001), 6MWT (p < 0.001), 10mWT (p < 0.001) and 5 R-STS (p = 0.004) were all improved. HIIT is feasible and safe in the early subacute post-stroke stage and is perceived by patients as highly credible, meeting their expectations of recovery.

Top-Down and Bottom-Up Mechanisms of Motor Recovery Poststroke

Stroke remains a leading cause of disability. Motor recovery requires the interaction of top-down and bottom-up mechanisms, which reinforce each other. Injury to the brain initiates a biphasic neuroimmune process, which opens a window for spontaneous recovery during which the brain is particularly sensitive to activity. Physical activity during this sensitive period can lead to rapid recovery by potentiating anti-inflammatory and neuroplastic processes. On the other hand, lack of physical activity can lead to early closure of the sensitive period and downstream changes in muscles, such as sarcopenia, muscle stiffness, and reduced cardiovascular capacity, and blood flow that impede recovery.

Integrating Cardiac Rehabilitation in Stroke Recovery

Stroke remains a top contributor to long-term disability in the United States and substantially limits a person's physical activity. Decreased cardiovascular capacity is a major contributing factor to activity limitations and is a significant health concern. Addressing the cardiovascular capacity of stroke survivors as part of poststroke management results in significant improvements in their endurance, functional recovery, and medical outcomes such as all-cause rehospitalization and mortality. Incorporation of a structured approach similar to the cardiac rehabilitation program, including aerobic exercise and risk factor education, can lead to improved cardiovascular function, health benefits, and quality of life in stroke survivors.

Challenge Level Contributes to the Efficacy of Treadmill Interventions after Stroke: A Systematic Review and Meta-Analysis

Intervention parameters such as the challenge, amount, and dosage (challenge × amount) have the potential to alter the efficacy of rehabilitation interventions after stroke. This systematic review investigated the effect of intervention parameters of challenge, amount, and dosage on improvements in walking outcomes following treadmill training (TT) and comparison interventions in people with stroke. Randomized controlled trials were included if they: (i) investigated interventions of TT or bodyweight-supported TT (BWSTT); (ii) made comparisons with other physiotherapy interventions, other types of TT, or no intervention; (iii) studied people with stroke; (iv) reported sufficient data on challenge and amount parameters; and (v) measured walking speed or endurance. Completeness of reporting was evaluated using the TIDieR-Rehab checklist and risk of bias was assessed using the revised Cochrane risk-of-bias tool. The review included 26 studies; 15 studies compared TT or BWSTT with other physiotherapy interventions and 11 studies compared different types of TT. Meta-analyses provided evidence with low to moderate certainty that greater differences in challenge and dosage between treadmill and comparison physiotherapy interventions produced greater effects on walking endurance (p < 0.01). However, challenge and dosage did not influence walking speed outcomes. The analysis of intervention amount was limited by the lack of studies that manipulated the amount of intervention. Overall, the findings indicate that, after stroke, some of the efficacy of TT on walking endurance can be explained by the challenge level during training. This supports the implementation of TT at higher challenge levels in stroke rehabilitation practice.

The safety and feasibility of early cardiorespiratory fitness testing after stroke

BACKGROUND

Cardiorespiratory fitness testing is recommended as part of a pre-exercise evaluation to aid the programming of safe, tailored cardiorespiratory fitness training after stroke. But there is limited evidence for its safety and feasibility in people with stroke with varying impairment levels in the early subacute phase of stroke recovery.

OBJECTIVE

To assess the safety and feasibility of cardiorespiratory fitness testing in the early subacute phase after stroke.

DESIGN

A sub-study of a larger single service, multi-site, prospective cohort feasibility study (Cardiac Rehabilitation in Stroke Survivors to Improve Survivorship [CRiSSIS]).

SETTING

Private subacute inpatient rehabilitation facilities.

PARTICIPANTS

Consecutive admissions of people with ischemic stroke admitted to subacute rehabilitation facilities.

INTERVENTION

Not applicable.

MAIN OUTCOME(S)

Safety was determined by the occurrence of adverse or serious adverse events. Feasibility was determined by assessing the (1) number of participants recruited and (2) number of participants able to complete the fitness test.

RESULTS

Between April 2018 and December 2019, a total of 165 people with stroke were screened to participate; 109 were eligible and 65 were recruited. Of the 62 who completed testing, 41 participants were able to complete a submaximal fitness test at a median of 12 days post-stroke. One minor adverse event was recorded. Of the 21 participants unable to complete the fitness test; 4 declined to complete the test, 9 were unable to commence the test, and 8 were unable to complete the first stage of the protocol due to stroke-related impairments. Participants with mild stroke, greater motor and cognitive function, and fewer depressive symptoms were more likely to be able to complete the cardiorespiratory fitness test.

CONCLUSION

Cardiorespiratory fitness testing was safe for most people with mild-to-moderately severe ischemic stroke and transient ischemic attack in the early subacute phase, but only two-thirds of the participants could complete the test.

Factors That Influence the Clinical Implementation of Aerobic Exercise in Stroke Rehabilitation: A Theory-Informed Qualitative Study

OBJECTIVE

Best practice guidelines recommend that aerobic exercise (AEx) be implemented as early as possible poststroke, yet the prescription of AEx remains limited in stroke rehabilitation settings. This study used theoretical frameworks to obtain an in-depth understanding of barriers and enablers to AEx implementation in the stroke rehabilitation setting.

METHODS

A qualitative, descriptive study was conducted. Participants were recruited from 4 stroke rehabilitation settings in Ontario, Canada, that have participated in an implementation study to provide structured AEx programming as part of standard care. Six clinician focus groups (with 19 physical therapists and 5 rehabilitation assistants) and one-to-one interviews with 7 managers and 1 physician were conducted to explore barriers and enablers to AEx implementation. The Theoretical Domains Framework and Consolidated Framework for Implementation Research informed content analysis for clinician and manager perspectives, respectively.

RESULTS

Barriers specific to resource constraints and health care system pressures, combined with patient goals, led to interventions to improve function being prioritized over AEx. Successful implementation was enabled through an interprofessional approach and team engagement in the planning and implementation process. Health care providers described concerns about patient safety, but confidence and capability for implementing AEx were enabled by education, skill development, use of exercise tests, and consultation with individuals with content expertise. Participants described the development of supportive processes that enabled AEx implementation within team workflows and shared resources.

CONCLUSION

Strategies to support implementation of AEx in stroke rehabilitation should incorporate knowledge and skills, the provision of clinical decision-making tools, access to expert consultation, the roles and social influence of the interprofessional team and formal and informal leaders, and supportive processes adapted to the local context.

IMPACT

Results from this study will inform the development of a clinical implementation toolkit to support clinical uptake of AEx in the stroke rehabilitation setting.

Are Physical Therapeutics Important for Stroke Patients to Recover Their Cardiorespiratory Fitness?

Background and Objectives: Aspects of improving cardiorespiratory fitness should be factored into therapeutics for recovery of movement in stroke patients. This study aimed to recommend optimized cardiorespiratory fitness therapeutics that can be prescribed to stroke patients based on a literature review and an expert-modified Delphi technique. Materials and Methods: we searched PubMed, Embase, CINAHL, and Cochrane databases and yielded 13,498 articles published from 2010 to 2019 to support the development of drafts. After applying the exclusion criteria, 29 documents were analyzed (drafts, 17 articles; modified Delphi techniques, 12 articles). This literature was reviewed in combination with the results of a modified Delphi technique presented to experts in the physical medicine and rehabilitation field. Analysis of the literature and survey results was conducted at the participating university hospital. Results: the results of this analysis were as follows: first, 12 intervention items derived through a researcher’s literature review and a Delphi technique questionnaire were constructed using the Likert scale; second, we asked the experts to create two modified Delphi techniques by reconstructing the items after statistical analysis for each order comprising five categories, and 15 items were finally confirmed. Conclusions: the recommendations in this study may lead to the development of a standard decision-making process for physiotherapists to improve their patients’ cardiorespiratory fitness. Moreover, the study results can help prescribers document patient care to reduce prescription errors and improve safety. In the future, multidisciplinary studies could potentially provide better therapeutics alternatives for cardiorespiratory fitness.

Normobaric Hypoxia Exposure During Treadmill Aerobic Exercise After Stroke: A Safety and Feasibility Study

Objective

To evaluate the safety and feasibility of performing treadmill aerobic exercise in moderate normobaric hypoxia among chronic hemiparetic stroke survivors.

Design

Observational study using convenience sampling.

Setting

Research laboratory in a tertiary rehabilitation hospital.

Participants

Chronic hemiparetic stroke survivors who could walk at least 10-m with or without assistance and had no absolute contraindications to exercise testing.

Intervention

Participants (three male and four female) were asked to complete three normobaric hypoxia exposure protocols within a single session. First, they were passively exposed to normobaric hypoxia through gradual reductions in the fraction of inspired oxygen (F_IO₂ = 20.9, 17.0, and 15.0%) while seated (5-min at each level of F_IO₂). Participants were then exposed to the same reductions in F_IO₂ during constant-load exercise performed on a treadmill at 40% of heart rate reserve. Finally, participants completed 20-min of exercise while intermittently exposed to moderate normobaric hypoxia (5 × 2-min at F_IO₂ = 15.0%) interspaced with 2-min normoxia intervals (F_IO₂ = 20.9%).

Outcome Measures

The primary outcome was occurrence of adverse events, which included standardized criteria for terminating exercise testing, blood oxygen saturation (SpO₂) <80%, or acute mountain sickness score >2. The increased cardiovascular strain imposed by normobaric hypoxia exposure at rest and during exercise was evaluated by changes in SpO₂, heart rate (HR), blood pressure, and rating of perceived exertion (RPE).

Results

One participant reported mild symptoms of nausea during exercise in normobaric hypoxia and discontinued participation. No other adverse events were recorded. Intermittent normobaric hypoxia exposure was associated with reduced SpO₂ (MD = −7.4%, CI: −9.8 to −5.0) and increased HR (MD = 8.2, CI: 4.6 to 11.7) compared to intervals while breathing typical room air throughout the 20-min constant-load exercise period. The increase in HR was associated with a 10% increase in relative effort. However, reducing F_IO₂ had little effect on blood pressure and RPE measurements.

Conclusion

Moderate normobaric hypoxia appeared to be a safe and feasible method to increase the cardiovascular strain of submaximal exercise in chronic hemiparetic stroke survivors. Future studies evaluating the effects of pairing normobaric hypoxia exposure with existing therapies on secondary prevention and functional recovery are warranted.

Assessment for cardiovascular fitness in patients with stroke: which cardiopulmonary exercise testing method is better?

Background: Assessment for cardiovascular disease (CVD) is important in stroke patients, both being one of the main factors limiting success in stroke rehabilitation and its increased risk in stroke patients. Reduced exercise capacity after stroke decreases patients' functionality and further increases the risk of CVD. Carefully selected cardiopulmonary exercise testing (CPET) can be safely used to determine the risk of CVD and to prescribe exercise program in stroke rehabilitation.Objectives: The primary purpose of this study is to determine the most appropriate CPET in patients with stroke. The secondary aim is to determine the relationship between cardiorespiratory fitness and functional status of the patients.Methods: Two CPETs using treadmill and bicycle ergometer protocols determined with a preliminary study were performed on participants. The main outcome measure was VO_2peak. Patients were also evaluated according to Brunnstrom motor staging, Modified Ashworth Scale, Berg Balance Scale, and Functional Independence Measure.Results: In total, 38 patients reached higher VO_2peak values at treadmill test compared to bicycle test (p < 0.001). The mean VO₂peak reached at treadmill CPET was 62% of the control group where mean VO_2peak reached at bicycle was 76% of the control group. No significant correlation was found between Brunnstrom staging, spasticity, Berg Balance Scale, and VO_2peak .Discussion: The results of this study indicate that CPET can be performed safely in stroke patients when appropriate protocol was selected and that treadmill was more appropriate to determine cardiorespiratory fitness in this study population.

Significance of Cycle Ergometer as a Measure of Peak Aerobic Capacity in the Disabled

BACKGROUND

To compare different physiological responses between treadmill and cycle ergometer in stroke patients in regard to community ambulation, and to determine strong predictors of equipment-dependent VO_2peak and its related factors among physical fitness parameters and finally to establish the significance of cycle ergometer as a measure of VO_2peak in the disabled according to gait function.

METHODS

Sixty-three stroke survivors were enrolled in this study and were grouped according to the gait speed (32 non-community ambulators <0.8 m/s:31 community ambulators ≥0.8 m/s). All participants performed exercise stress test (EST) with treadmill and cycle ergometer and rehabilitation function tests.

RESULTS

Community ambulators achieved higher VO_2peak by treadmill, but non-community ambulators showed similar VO_2peak between treadmill and cycle ergometer due to gait problems. The gait speed and endurance were strong predictors of difference of peak aerobic capacity between treadmill and cycle ergometer (multiple regression analysis, adjusted R²=0.458).

CONCLUSION

Cycle ergometer might be more appropriate for non-community ambulatory stroke patients to assess the peak aerobic capacity. Gait speed and gait distance could affect equipment-dependent cardiopulmonary performance significantly in the disabled. Therefore, the careful consideration of comprehensive and objective physical function including gait endurance, and speed and prescription of appropriate exercise intensity and equipment depending on the severity should be needed to improve the cardiopulmonary fitness and physical function adequately in stroke rehabilitation.

Cardiorespiratory strain during stroke rehabilitation: Are patients trained enough? A systematic review

BACKGROUND

Rehabilitation is a mandatory component of stroke management, aiming to recover functional capacity and independence. To that end, physical therapy sessions must involve adequate intensity in terms of cardiopulmonary stress to meet the physiological demands of independent living.

OBJECTIVE

The aim of this systematic review was to determine the current level of cardiopulmonary strain during rehabilitation sessions in stroke patients.

METHODS

Three electronic databases (PubMed, CINAHL and Embase. com) were searched to identify observational studies that documented cardiopulmonary strain during rehabilitation sessions in post-stroke patients (last search performed in February 2019). A manual cross-referencing search was also performed. To be included, articles needed to report data related to both cardiopulmonary strain (heart rate, oxygen consumption or energy expenditure) and active therapy time. The methodological quality of each study was assessed with the Evidence-Based Librarianship Critical Appraisal Tool. Data related to both cardiorespiratory strain and active therapy time were extracted from selected articles.

RESULTS

Four of 43 full-text articles assessed for eligibility met the inclusion criteria. Results extracted from these articles suggested that the intensity of rehabilitation sessions was insufficient to induce a cardiopulmonary training effect in a post-stroke context as measured by metabolic stress. Patients were inactive from 21% to 80% of the therapy time. The Evidence-Based Librarianship tool scores ranged from 65% (15/23) to 91% (21/23), which indicates questionable to good quality.

CONCLUSION

The current literature on cardiopulmonary solicitation during stroke rehabilitation sessions is poor in terms of both the number of studies available and their methodological quality. Summarized results tend to support previous claims that rehabilitation sessions offered to stroke patients are of suboptimal cardiopulmonary strain, which can interfere with their capacity to regain functional independence.

Determining Safe Participation in Aerobic Exercise Early After Stroke Through a Graded Submaximal Exercise Test

OBJECTIVE

The benefits of aerobic exercise early after stroke are well known, but concerns about cardiovascular risk are a barrier to clinical implementation. Symptom-limited exercise testing with electrocardiography (ECG) is recommended but not always feasible. The purpose of this study was to determine the frequency of and corresponding exercise intensities at which ECG abnormalities occurred during submaximal exercise testing that would limit safe exercise prescription beyond those intensities.

METHODS

This study was a retrospective analysis of ECGs from 195 patients who completed submaximal exercise testing during stroke rehabilitation. A graded submaximal exercise test was conducted with a 5- or 12-lead ECG and was terminated on the basis of predetermined endpoint criteria (heart rate, perceived exertion, signs, or symptoms). ECGs were retrospectively reviewed for exercise-induced abnormalities and their associated heart rates.

RESULTS

The peak heart rate achieved was 65.4% (SD = 10.5%) of the predicted maximum heart rate or 29.1% (SD = 15.5%) of the heart rate reserve (adjusted for beta-blocker medications). The test was terminated more often because of perceived exertion (93/195) than because of heart rate limits (60/195). Four patients (2.1%) exhibited exercise-induced horizontal or downsloping ST segment depression of ≥1 mm. Except for 1 patient, the heart rate at test termination was comparable with the heart rate associated with the onset of the ECG abnormality.

CONCLUSION

A graded submaximal exercise test without ECG but with symptom monitoring and conservative heart rate and perceived exertion endpoints may facilitate safe exercise intensities early after stroke. Symptom-limited exercise testing with ECG is still recommended when progressing to higher intensity exercise.

IMPACT

Concerns about cardiovascular risk are a barrier to physical therapists implementing aerobic exercise in stroke rehabilitation. This study showed that, in the absence of access to exercise testing with ECG, submaximal testing with conservative heart rate and perceived exertion endpoints and symptom monitoring can support physical therapists in the safe prescription of aerobic exercise early after stroke.

LAY SUMMARY

It is recommended that people with stroke participate in aerobic exercise as early as possible during their rehabilitation. A submaximal exercise test with monitoring of heart rate, perceived exertion, blood pressure, and symptoms can support physical therapists in safely prescribing that exercise.

Noninvasive investigation of the cardiodynamic response to 6MWT in people after stroke using impedance cardiography

This is a cross-section observational study that investigated the cardiodynamic response to a 6-minute walk test (6MWT) in patients after stroke using impedance cardiography (ICG). Patients diagnosed with stroke were invited to participate in a 6MWT on consecutive days. Heart rate (HR), cardiac output (CO), stroke volume (SV) and cardiac index (CI) were measured by ICG using the PhysioFlow^® PF07 Enduro^TM at 1-second intervals for 10 minutes prior to, during and for 10 minutes after each 6MWT. Oxygen saturation, perceived exertion score (modified Borg scale) and the distance covered at the end of each 6MWT were recorded. Twenty-nine patients (mean age 55.6±10.9 years) completed the study. The mean duration of stroke after diagnosis was 14.4±19.1 months. There were no differences in the measured data between the first and second 6MWT (mean intraclass correlation coefficient (ICC) range: 0.87–0.95). The 6 minute walk distance (6WMD) covered in the two 6MWTs was 246±126 and 255±130m respectively (p>0.05). Mean measured data for each subject at rest, and at the end of the better performed 6MWT were, respectively: HR 78±11 and 100±18 bpm; CO 5.5±1.2 and 8.9±2.6 l/min, SV 71.3±16 and 89.3±18.6 ml/beat and CI 3.0±0.6 and 4.9±1.3 l/min/m². After commencement of the 6MWT, the increase in SV took 30 sec before the rise approaching a plateau, whereas HR, CO and CI continued to rise steeply for 90 sec before leveling off to a steady rise. After completion of the 6MWT, all parameters had returned to baseline by a mean of 3.5 min. Sub-group analysis showed that the increase in cardiac output was predominantly contributed by an increase in heart rate in participants diagnosed with stroke for less than 1 year, whereas both stroke volume and heart rate contributed similarly to the increase in cardiac output in participants with diagnosis of stroke for longer than 1 year. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) both returned to baseline within 2 minutes post 6MWT. HR recorded at the end of the 6MWT was 60.8±10.6% of the predicted maximal heart rate and perceived exertion score was 5±2. Correlations between 6MWD and HR, and between 6MWD and SV were weak, with correlation coefficients Spearman’s rho (r_s) =0.46, and 0.42, respectively (p<0.05). Correlation between 6MWD and CO and CI were higher (r_s= 0.66 and 0.63, respectively (p<0.01)). This is the first study to report cardiac responses during a 6MWT in stroke patients. ICG is a reliable, non-invasive, repeatable method of measuring cardiodynamic data in stroke patients.

Safety of Performing a Graded Exercise Test Early after Stroke and Transient Ischemic Attack

BACKGROUND

Low cardiorespiratory fitness (CRF) is a predictor of stroke risk and poor outcome poststroke. Fitness levels are rarely assessed in the acute phase and it is unclear if it is safe for stroke survivors and people with transient ischemic attack (TIA) to perform a graded exercise test to assess fitness.

OBJECTIVE

To determine if people within 14 days post stroke can safely perform a graded exercise test.

DESIGN

Observational study.

SETTING

Research institute.

PARTICIPANTS

People with stroke or TIA admitted to an acute stroke unit.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Safety of performing a graded exercise test early post stroke. Safety outcomes were (1) occurrence of an adverse event or (2) <85% blood oxygen saturation (SpO₂ ). Participants performed a graded exercise test on a recumbent stepper at a research institute <2 weeks postevent. CRF was determined by measuring peak volume of oxygen uptake (VO_2peak ) using a metabolic cart.

RESULTS

Twenty-nine participants were enrolled in the study (median age 69 years; interquartile range 58-75). Sixteen were diagnosed with TIA and 13 with a mild stroke. Twenty-eight participants completed the test; one participant was unable to perform the test due to back pain. The test was terminated due to standardized stopping criteria in 26 cases (5 = volitional fatigue, 6 = unable to keep required cadence, 15 = reaching 85% HR_max ), one due to safety (ie, SpO₂  < 85%), and one was inadvertently terminated before stopping criteria were reached. Average CRF determined by the exercise test was low; mean VO_2peak of 16.2 ± 4.5 mL/kg/min for men (n = 20) and 12.4 ± 3.6 mL/kg/min for women (n = 8).

CONCLUSIONS

Determining exercise capacity early post stroke and TIA using a graded exercise test appears to be safe in patients with mild deficits. This information should be useful to plan tailored exercise programs. Further research should focus on determining safety of exercise testing in more severely affected stroke survivors.

Cardiorespiratory factors related to the increase in oxygen consumption during exercise in individuals with stroke

BACKGROUND

Understanding the cardiorespiratory factors related to the increase in oxygen consumption ([Formula: see text]) during exercise is essential for improving cardiorespiratory fitness in individuals with stroke. However, cardiorespiratory factors related to the increase in [Formula: see text] during exercise in these individuals have not been examined using multivariate analysis. This study aimed to identify cardiorespiratory factors related to the increase in [Formula: see text] during a graded exercise in terms of respiratory function, cardiac function, and the ability of skeletal muscles to extract oxygen.

METHODS

Eighteen individuals with stroke (aged 60.1 ± 9.4 years, 67.1 ± 30.8 days poststroke) underwent a graded exercise test for the assessment of cardiorespiratory response to exercise. The increases in [Formula: see text] from rest to first threshold and that from rest to peak exercise were measured as a dependent variable. The increases in respiratory rate, tidal volume, minute ventilation, heart rate, stroke volume, cardiac output, and arterial-venous oxygen difference from rest to first threshold and those from rest to peak exercise were measured as the independent variables.

RESULTS

From rest to first threshold, the increases in arterial-venous oxygen difference (β = 0.711) and cardiac output (β = 0.572) were significant independent variables for the increase in [Formula: see text] (adjusted R2 = 0.877 p < 0.001). Similarly, from rest to peak exercise, the increases in arterial-venous oxygen difference (β = 0.665) and cardiac output (β = 0.636) were significant factors related to the increase in [Formula: see text] (adjusted R2 = 0.923, p < 0.001).

CONCLUSION

Our results suggest that the ability of skeletal muscle to extract oxygen is a major cardiorespiratory factor related to the increase in [Formula: see text] during exercise testing in individuals with stroke. For improved cardiorespiratory fitness in individuals with stroke, the amount of functional muscle mass during exercise may need to be increased.

People With Aneurysmal Subarachnoid Hemorrhage Have Low Physical Fitness and Can Be Predisposed to Inactive and Sedentary Lifestyles

BACKGROUND

Physical inactivity, sedentary lifestyles, and low functional outcome are thought to impact the level of physical fitness in patients with aneurysmal subarachnoid hemorrhage (a-SAH). However, changes in fitness over time and associated factors have not been studied in a-SAH.

OBJECTIVE

The objective was to evaluate the level of physical fitness in the first year after a-SAH and explore longitudinal relations with physical activity, sedentary behavior, and functional outcome. Additionally, we evaluated whether physical fitness could be predicted by disease-related characteristics (ie, severity of a-SAH, location of the aneurysm, treatment procedure, pituitary dysfunction, and complications).

DESIGN

This was a prospective 1-year follow-up study.

METHODS

Fifty-two participants performed exercise testing at 6 and 12 months after a-SAH. Cardiopulmonary exercise testing and isokinetic dynamometry were applied to determine the peak oxygen uptake $({\rm{\dot{V}}}{{\rm{o}}_{2{\rm{peak}}}})$ and the peak torque of the knee extensors (PText) and flexors (PTflex). In addition, physical activity and sedentary behavior were evaluated by accelerometer-based activity monitoring. The functional outcome was assessed by the Functional Independence Measure and Functional Assessment Measure. Disease-related characteristics were collected at hospital intake.

RESULTS

At both 6 and 12 months, all fitness parameters were lower compared with predicted values (ranging from 18% to 28%). Physical activity is related to both ${\rm{\dot{V}}}{{\rm{o}}_{{\rm{2peak}}}}$ and PTflex. The Functional Independence Measure and Functional Assessment Measure scores was related to PText and PTflex. Further, participants who underwent surgical clipping had lower ${\rm{\dot{V}}}{{\rm{o}}_{{\rm{2peak}}}}$ and PTflex.

LIMITATIONS

Longitudinal observations cannot confirm causality.

CONCLUSIONS

Levels of physical fitness remain low over the first year after a-SAH. Participants who were physically more active had higher levels of physical fitness, whereas participants with impaired functional outcome or who were treated with surgical clipping were at risk of low physical fitness. Exercise interventions are warranted and should focus on the promotion of physical activity and target patients with impaired functional outcome or those who have been treated with surgical clipping.

Influence of an exercise program on cardiac remodeling and functional capacity in patients with stroke (CRONuS trial): study protocol for a randomized controlled trial

BACKGROUND

Cardiovascular rehabilitation is one of the treatment options for post-stroke individuals in order to improve functional independence in activities of daily life and reduce energy expenditure. The aim of this trial is to evaluate the effect of an exercise program on the echocardiographic variables, functional capacity, inflammatory response, neurological status, nutritional status, cardiologic evaluation, and quality of life of patients after stroke.

METHODS/DESIGN

This is a randomized controlled trial including patients with ischemic stroke in the chronic phase. The patients will be evaluated at the beginning of the study and after 16 weeks. This will include clinical and physical evaluation, 6-min walk test, neurological assessment, nutritional assessment, ambulatory blood pressure monitoring, transthoracic echocardiography, and assessment of the quality of life. The sample size has been determined as 40 patients, who will be divided into two groups: control group (CG; n = 20) and intervention group (IG; n = 20). The CG will undergo conventional physiotherapy for 45 min, three times a week, up to 16 weeks, while the IG will be put on a cardiovascular rehabilitation program consisting of heating, aerobic exercise, and muscle strengthening for 45 min, three times a week, for 16 weeks. The primary endpoint will be functional capacity following a 6-min walk test (delta maxVO₂) and morphofunctional echocardiographic variables (indexed left ventricular mass) before and after the intervention.

DISCUSSION

We expect to observe an improvement in cardiac structural and functional abnormalities in the IG, on echocardiography and biochemical examination, and that the improvement of these parameters after cardiovascular rehabilitation will have a favorable impact on the functional capacity and quality of life of patients after stroke.

TRIAL REGISTRATION

REBEC, RBR-4wk4b3. Registered on 19 September 2016.

Physiological Responses and Perceived Exertion During Robot-Assisted and Body Weight-Supported Gait After Stroke

INTRODUCTION

Physiological responses are rarely considered during walking after stroke and if considered, only during a short period (3-6 minutes). The aims of this study were to examine physiological responses during 30-minute robot-assisted and body weight-supported treadmill and overground walking and compare intensities with exercise guidelines.

METHODS

A total of 14 ambulatory stroke survivors (age: 61 ± 9 years; time after stroke: 2.8 ± 2.8 months) participated in 3 separate randomized walking trials. Patients walked overground, on a treadmill, and in the Lokomat (60% robotic guidance) for 30 minutes at matched speeds (2.0 ± 0.5 km/h) and matched levels of body weight support (BWS; 41% ± 16%). Breath-by-breath gas analysis, heart rate, and perceived exertion were assessed continuously.

RESULTS

Net oxygen consumption, net carbon dioxide production, net heart rate, and net minute ventilation were about half as high during robot-assisted gait as during body weight-supported treadmill and overground walking ( P < .05). Net minute ventilation, net breathing frequency, and net perceived exertion significantly increased between 6 and 30 minutes (respectively, 1.8 L/min, 2 breaths/min, and 3.8 units). During Lokomat walking, exercise intensity was significantly below exercise recommendations; during body weight-supported overground and treadmill walking, minimum thresholds were reached (except for percentage of heart rate reserve during treadmill walking).

CONCLUSION

In ambulatory stroke survivors, the oxygen and cardiorespiratory demand during robot-assisted gait at constant workload are considerably lower than during overground and treadmill walking at matched speeds and levels of body weight support. Future studies should examine how robotic devices can be Future studies should examine how robotic devices can be exploited to induce aerobic exercise.

Four birds with one stone? Reparative, neuroplastic, cardiorespiratory, and metabolic benefits of aerobic exercise poststroke

PURPOSE OF REVIEW

Converging evidence from animal models of stroke and clinical trials suggests that aerobic exercise has effects across multiple targets.

RECENT FINDINGS

The subacute phase is characterized by a period of heightened neuroplasticity when aerobic exercise has the potential to optimize recovery. In animals, low intensity aerobic exercise shrinks lesion size and reduces cell death and inflammation, beginning 24 h poststroke. Also in animals, aerobic exercise upregulates brain-derived neurotrophic factor near the lesion and improves learning. In terms of neuroplastic effects, clinical trial results are less convincing and have only examined effects in chronic stroke. Stroke patients demonstrate cardiorespiratory fitness levels below the threshold required to carry out daily activities. This may contribute to a 'neurorehabilitation ceiling' that limits capacity to practice at a high enough frequency and intensity to promote recovery. Aerobic exercise when delivered 2-5 days per week at moderate to high intensity beginning as early as 5 days poststroke improves cardiorespiratory fitness, dyslipidemia, and glucose tolerance.

SUMMARY

Based on the evidence discussed and applying principles of periodization commonly used to prepare athletes for competition, we have created a model of aerobic training in subacute stroke in which training is delivered in density blocks (duration × intensity) matched to recovery phases.

Unilateral Arm Crank Exercise Test for Assessing Cardiorespiratory Fitness in Individuals with Hemiparetic Stroke

Cardiorespiratory fitness assessment with leg cycle exercise testing may be influenced by motor impairments in the paretic lower extremity. Hence, this study examined the usefulness of a unilateral arm crank exercise test to assess cardiorespiratory fitness in individuals with stroke, including sixteen individuals with hemiparetic stroke (mean ± SD age, 56.4 ± 7.5 years) and 12 age- and sex-matched healthy controls. Participants performed the unilateral arm crank and leg cycle exercise tests to measure oxygen consumption ([Formula: see text]O2) and heart rate at peak exercise. The [Formula: see text]O2 at peak exercise during the unilateral arm crank exercise test was significantly lower in the stroke group than in the control group (p < 0.001). In the stroke group, the heart rate at peak exercise during the unilateral arm crank exercise test did not significantly correlate with the Brunnstrom recovery stages of the lower extremity (p = 0.137), whereas there was a significant correlation during the leg cycle exercise test (rho = 0.775, p < 0.001). The unilateral arm crank exercise test can detect the deterioration of cardiorespiratory fitness independently of lower extremity motor impairment severity in individuals with hemiparetic stroke. This study is registered with UMIN000014733.

Rhythmic arm cycling training improves walking and neurophysiological integrity in chronic stroke: the arms can give legs a helping hand in rehabilitation

Training locomotor central pattern-generating networks (CPGs) through arm and leg cycling improves walking in chronic stroke. These outcomes are presumed to result from enhanced interlimb connectivity and CPG function. The extent to which rhythmic arm training activates interlimb CPG networks for locomotion remains unclear and was assessed by studying chronic stroke participants before and after 5 wk of arm cycling training. Strength was assessed bilaterally via maximal voluntary isometric contractions in the legs and hands. Muscle activation during arm cycling and transfer to treadmill walking were assessed in the more affected (MA) and less affected (LA) sides via surface electromyography. Changes to interlimb coupling during rhythmic movement were evaluated using modulation of cutaneous reflexes elicited by electrical stimulation of the superficial radial nerve at the wrist. Bilateral soleus stretch reflexes were elicited at rest and during 1-Hz arm cycling. Clinical function tests assessed walking, balance, and motor function. Results show significant changes in function and neurophysiological integrity. Training increased bilateral grip strength, force during MA plantarflexion, and muscle activation. "Normalization" of cutaneous reflex modulation was found during arm cycling. There was enhanced activity in the dorsiflexor muscles on the MA side during the swing phase of walking. Enhanced interlimb coupling was shown by increased modulation of MA soleus stretch reflex amplitudes during arm cycling after training. Clinical evaluations showed enhanced walking ability and balance. These results are consistent with training-induced changes in CPG function and interlimb connectivity and underscore the need for arm training in the functional rehabilitation of walking after neurotrauma. NEW & NOTEWORTHY It has been suggested but not tested that training the arms may influence rehabilitation of walking due to activation of interneuronal patterning networks after stroke. We show that arm cycling training improves strength, clinical function, coordination of muscle activity during walking, and neurological connectivity between the arms and the legs. The arms can, in fact, give the legs a helping hand in rehabilitation of walking after stroke.

Influence of pilates training on the quality of life of chronic stroke patients

[Purpose] This study was to observe the influence of Pilates training on the quality of life in chronic stoke patients. [Subjects and Methods] Forty chronic stroke patients participated in this study. They were divided into same number of experimental group (EG) and control group (CG). EG participated in a 60-min Pilates training program, twice a week for 12 weeks, while the CG did not participate in any exercise-related activities for the duration and participating in general occupational therapy without any exercise-related activities. Then the MMSE-K was performed before and after Pilates training to observe the influence of Pilates training on the quality of life in chronic stroke patients. [Results] Statistically significant improvement in the physical, social, and psychological domains was found in EG after the training. No statistically significant difference was found in all three quality of life domains for the CG. EG experienced a statistically significant improvement in all quality of life domains compared with that of CG. [Conclusion] Therefore, participation in Pilates training was found to effectively improve the quality of life in stroke patients. Pilates training involves low and intermediate intensity resistance and repetition that match the patient’s physical ability and can be a remedial exercise program that can improve physical ability and influence quality of life.

A Single Bout of High-Intensity Interval Training Improves Motor Skill Retention in Individuals With Stroke

BACKGROUND

One bout of high-intensity cardiovascular exercise performed immediately after practicing a motor skill promotes changes in the neuroplasticity of the motor cortex and facilitates motor learning in nondisabled individuals.

OBJECTIVE

To determine if a bout of exercise performed at high intensity is sufficient to induce neuroplastic changes and improve motor skill retention in patients with chronic stroke.

METHODS

Twenty-two patients with different levels of motor impairment were recruited. On the first session, the effects of a maximal graded exercise test on corticospinal and intracortical excitability were assessed from the affected and unaffected primary motor cortex representational area of a hand muscle with transcranial magnetic stimulation. On the second session, participants were randomly assigned to an exercise or a nonexercise control group. Immediately after practicing a motor task, the exercise group performed 15 minutes of high-intensity interval training while the control group rested. Twenty-four hours after motor practice all participants completed a test of the motor task to assess skill retention.

RESULTS

The graded exercise test reduced interhemispheric imbalances in GABA_A-mediated short-interval intracortical inhibition but changes in other markers of excitability were not statistically significant. The group that performed high-intensity interval training showed a better retention of the motor skill.

CONCLUSIONS

The performance of a maximal graded exercise test triggers only modest neuroplastic changes in patients with chronic stroke. However, a single bout of high-intensity interval training performed immediately after motor practice improves skill retention, which could potentially accelerate motor recovery in these individuals.

Promoting Optimal Physical Exercise for Life (PROPEL): aerobic exercise and self-management early after stroke to increase daily physical activity-study protocol for a stepped-wedge randomised trial

INTRODUCTION

Physical exercise after stroke is essential for improving recovery and general health, and reducing future stroke risk. However, people with stroke are not sufficiently active on return to the community after rehabilitation. We developed the Promoting Optimal Physical Exercise for Life (PROPEL) programme, which combines exercise with self-management strategies within rehabilitation to promote ongoing physical activity in the community after rehabilitation. This study aims to evaluate the effect of PROPEL on long-term participation in exercise after discharge from stroke rehabilitation. We hypothesise that individuals who complete PROPEL will be more likely to meet recommended frequency, duration and intensity of exercise compared with individuals who do not complete the programme up to 6 months post discharge from stroke rehabilitation.

METHODS AND ANALYSIS

Individuals undergoing outpatient stroke rehabilitation at one of six hospitals will be recruited (target n=192 total). A stepped-wedge design will be employed; that is, the PROPEL intervention (group exercise plus self-management) will be 'rolled out' to each site at a random time within the study period. Prior to roll-out of the PROPEL intervention, sites will complete the control intervention (group aerobic exercise only). Participation in physical activity for 6 months post discharge will be measured via activity and heart rate monitors, and standardised physical activity questionnaire. Adherence to exercise guidelines will be evaluated by (1) number of 'active minutes' per week (from the activity monitor), (2) amount of time per week when heart rate is within a target range (ie, 55%-80% of age-predicted maximum) and (3) amount of time per week completing 'moderate' or 'strenuous' physical activities (from the questionnaire). We will compare the proportion of active and inactive individuals at 6 months post intervention using mixed-model logistic regression, with fixed effects of time and phase and random effect of cluster (site).

ETHICS AND DISSEMINATION

To date, research ethics approval has been received from five of the six sites, with conditional approval granted by the sixth site. Results will be disseminated directly to study participants at the end of the trial, and to other stake holders via publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT02951338; Pre-results.

The effects of Pilates exercise on cardiopulmonary function in the chronic stroke patients: a randomized controlled trials

[Purpose] The purpose of this study was to examine the effect of modified Pilates exercise on cardiopulmonary function in chronic stroke patients. [Subjects and Methods] Twenty participants (age, 62.7 ± 7.3 years; height, 163.3 ± 8.5 cm; weight, 68.8 ± 10.3 kg) were recruited for this study, and randomly allocated to the modified Pilates exercise group (n=10) or the control group (n=10). Graded submaximal treadmill exercise test was used to examine the status of patients' cardiopulmonary function, based on maximal oxygen intake, at the end of a patient's exercise tolerance limit. [Results] The resting heart rates, maximal oxygen intake, and maximal oxygen intake per kilogram were significantly different after 8 weeks of modified Pilates exercise. In addition, these variables were also significantly different between the Pilates and control groups after 8 weeks. [Conclusion] This study has demonstrated that 8 weeks of modified Pilates exercise program can have a positive influence on patients with chronic stroke, potentially by enhancing the cardiopulmonary function, which may have positive implications for increasing their functional ability.

Effectiveness of Active Cycling in Subacute Stroke Rehabilitation: A Randomized Controlled Trial

OBJECTIVE

To examine the effects of 3 months of aerobic training (AT) followed by coaching on aerobic capacity, strength, and gait speed after subacute stroke.

DESIGN

Randomized controlled trial.

SETTING

Inpatient rehabilitation center.

PARTICIPANTS

Patients (N=59; mean age ± SD, 65.4±10.3y; 21 women (36%); Barthel Index ≤50 in 64% of patients) with first stroke and able to cycle at 50 revolutions/min were enrolled in the study 3 to 10 weeks after stroke onset.

INTERVENTIONS

Patients were randomly allocated to a 3-month active cycling group (ACG, n=33) and education, or to a control group (CG, n=26). Afterward, patients in the ACG were randomly assigned either to a coaching (n=15) or to a noncoaching group (n=16) for 9 months.

MAIN OUTCOME MEASURES

Aerobic capacity, isometric knee extension strength, and gait ability and speed were measured before and after intervention and during follow-up at 6 and 12 months.

RESULTS

A nonsignificant difference was found in workload (Watt_peak) (P=.078) between ACG and CG after 3 months. Furthermore, after 3 months of cycling and after 9 months of coaching, all groups showed significant changes over time (P≤.027) in peak oxygen consumption, Watt_peak, leg strength, and gait speed. Also, significant changes over time (P<.001) were found in the ACG and the CG in patients with walking inability at baseline.

CONCLUSIONS

No significant differences between training groups were found over time. Although our study did not have objective exercise data from the training device during follow-up, the 3-month active cycling (AC) program combined with education sessions seemed an applicable method in subacute stroke rehabilitation. New long-term AT interventions should focus on coaching approaches to facilitate training after a supervised AC program.

The six-minute walk test predicts cardiorespiratory fitness in individuals with aneurysmal subarachnoid hemorrhage

BACKGROUND

Peak oxygen uptake (VO_2peak) established during progressive cardiopulmonary exercise testing (CPET) is the "gold-standard" for cardiorespiratory fitness. However, CPET measurements may be limited in patients with aneurysmal subarachnoid hemorrhage (a-SAH) by disease-related complaints, such as cardiovascular health-risks or anxiety. Furthermore, CPET with gas-exchange analyses require specialized knowledge and infrastructure with limited availability in most rehabilitation facilities.

OBJECTIVES

To determine whether an easy-to-administer six-minute walk test (6MWT) is a valid clinical alternative to progressive CPET in order to predict VO_2peak in individuals with a-SAH.

METHODS

Twenty-seven patients performed the 6MWT and CPET with gas-exchange analyses on a cycle ergometer. Univariate and multivariate regression models were made to investigate the predictability of VO_2peak from the six-minute walk distance (6MWD).

RESULTS

Univariate regression showed that the 6MWD was strongly related to VO_2peak (r = 0.75, p < 0.001), with an explained variance of 56% and a prediction error of 4.12 ml/kg/min, representing 18% of mean VO_2peak. Adding age and sex to an extended multivariate regression model improved this relationship (r = 0.82, p < 0.001), with an explained variance of 67% and a prediction error of 3.67 ml/kg/min corresponding to 16% of mean VO_2peak.

CONCLUSIONS

The 6MWT is an easy-to-administer submaximal exercise test that can be selected to estimate cardiorespiratory fitness at an aggregated level, in groups of patients with a-SAH, which may help to evaluate interventions in a clinical or research setting. However, the relatively large prediction error does not allow for an accurate prediction in individual patients.

Long-Term Plasticity in Reflex Excitability Induced by Five Weeks of Arm and Leg Cycling Training after Stroke

Neural connections remain partially viable after stroke, and access to these residual connections provides a substrate for training-induced plasticity. The objective of this project was to test if reflex excitability could be modified with arm and leg (A &amp; L) cycling training. Nineteen individuals with chronic stroke (more than six months postlesion) performed 30 min of A &amp; L cycling training three times a week for five weeks. Changes in reflex excitability were inferred from modulation of cutaneous and stretch reflexes. A multiple baseline (three pretests) within-subject control design was used. Plasticity in reflex excitability was determined as an increase in the conditioning effect of arm cycling on soleus stretch reflex amplitude on the more affected side, by the index of modulation, and by the modulation ratio between sides for cutaneous reflexes. In general, A &amp; L cycling training induces plasticity and modifies reflex excitability after stroke.

Test-retest reliability and four-week changes in cardiopulmonary fitness in stroke patients: evaluation using a robotics-assisted tilt table

BACKGROUND

Exercise testing devices for evaluating cardiopulmonary fitness in patients with severe disability after stroke are lacking, but we have adapted a robotics-assisted tilt table (RATT) for cardiopulmonary exercise testing (CPET). Using the RATT in a sample of patients after stroke, this study aimed to investigate test-retest reliability and repeatability of CPET and to prospectively investigate changes in cardiopulmonary outcomes over a period of four weeks.

METHODS

Stroke patients with all degrees of disability underwent 3 separate CPET sessions: 2 tests at baseline (TB1 and TB2) and 1 test at follow up (TF). TB1 and TB2 were at least 24 h apart. TB2 and TF were 4 weeks apart. A RATT equipped with force sensors in the thigh cuffs, a work rate estimation algorithm and a real-time visual feedback system was used to guide the patients' exercise work rate during CPET. Test-retest reliability and repeatability of CPET variables were analysed using paired t-tests, the intraclass correlation coefficient (ICC), the coefficient of variation (CoV), and Bland and Altman limits of agreement. Changes in cardiopulmonary fitness during four weeks were analysed using paired t-tests.

RESULTS

Seventeen sub-acute and chronic stroke patients (age 62.7 ± 10.4 years [mean ± SD]; 8 females) completed the test sessions. The median time post stroke was 350 days. There were 4 severely disabled, 1 moderately disabled and 12 mildly disabled patients. For test-retest, there were no statistically significant differences between TB1 and TB2 for most CPET variables. Peak oxygen uptake, peak heart rate, peak work rate and oxygen uptake at the ventilatory anaerobic threshold (VAT) and respiratory compensation point (RCP) showed good to excellent test-retest reliability (ICC 0.65-0.94). For all CPET variables, CoV was 4.1-14.5 %. The mean difference was close to zero in most of the CPET variables. There were no significant changes in most cardiopulmonary performance parameters during the 4-week period (TB2 vs TF).

CONCLUSIONS

These findings provide the first evidence of test-retest reliability and repeatability of the principal CPET variables using the novel RATT system and testing methodology, and high success rates in identification of VAT and RCP: good to excellent test-retest reliability and repeatability were found for all submaximal and maximal CPET variables. Reliability and repeatability of the main CPET parameters in stroke patients on the RATT were comparable to previous findings in stroke patients using standard exercise testing devices. The RATT has potential to be used as an alternative exercise testing device in patients who have limitations for use of standard exercise testing devices.

Effect of intensive aerobic exercise on respiratory capacity and walking ability with chronic stroke patients: a randomized controlled pilot trial

[Purpose] To investigate the effects of intensive aerobic exercise on respiratory capacity and walking ability in chronic stroke patients. [Subjects and Methods] The subjects were randomly assigned to an experimental group (n=6) or a control group (n=6). Patients in the experimental group received intensive aerobic exercise for 30 minutes and traditional physical therapy once a day, five days a week, for four weeks. The control group received aerobic exercise for 30 minutes and traditional physical therapy for 30 minutes a day, five days a week, for four weeks. [Results] After the intervention, both groups showed significant improvements in the forced vital capacity, forced expiratory volume in one second, 10-meter walking test, and six-minute walking test over the baseline results. The comparison of the two groups after the intervention revealed that the experimental group showed more significant improvements in the forced vital capacity, forced expiratory volume in one second, and six-minute walking test. There was no significant difference in saturation pulse oximetry oxygen and 10-meter walking test between the groups. [Conclusion] The results of this study suggest that intensive aerobic exercise has a positive effect on respiratory capacity and walking endurance in patients with chronic stroke.

Exploiting Interlimb Arm and Leg Connections for Walking Rehabilitation: A Training Intervention in Stroke

Rhythmic arm and leg (A&L) movements share common elements of neural control. The extent to which A&L cycling training can lead to training adaptations which transfer to improved walking function remains untested. The purpose of this study was to test the efficacy of A&L cycling training as a modality to improve locomotor function after stroke. Nineteen chronic stroke (>six months) participants were recruited and performed 30 minutes of A&L cycling training three times a week for five weeks. Changes in walking function were assessed with (1) clinical tests; (2) strength during isometric contractions; and (3) treadmill walking performance and cutaneous reflex modulation. A multiple baseline (3 pretests) within-subject control design was used. Data show that A&L cycling training improved clinical walking status increased strength by ~25%, improved modulation of muscle activity by ~25%, increased range of motion by ~20%, decreased stride duration, increased frequency, and improved modulation of cutaneous reflexes during treadmill walking. On most variables, the majority of participants showed a significant improvement in walking ability. These results suggest that exploiting arm and leg connections with A&L cycling training, an accessible and cost-effective training modality, could be used to improve walking ability after stroke.

Promoting Optimal Physical Exercise for Life: An Exercise and Self-Management Program to Encourage Participation in Physical Activity after Discharge from Stroke Rehabilitation-A Feasibility Study

People with stroke do not achieve adequate levels of physical exercise following discharge from rehabilitation. We developed a group exercise and self-management program (PROPEL), delivered during stroke rehabilitation, to promote uptake of physical activity after discharge. This study aimed to establish the feasibility of a larger study to evaluate the effect of this program on participation in self-directed physical activity. Participants with subacute stroke were recruited at discharge from one of three rehabilitation hospitals; one hospital offered the PROPEL program whereas the other two did not (comparison group; COMP). A high proportion (11/16) of eligible PROPEL program participants consented to the study. Fifteen COMP participants were also recruited. Compliance with wearing an accelerometer for 6 weeks continuously and completing physical activity questionnaires was high (>80%), whereas only 34% of daily heart rate data were available. Individuals who completed the PROPEL program seemed to have higher outcome expectations for exercise, fewer barriers to physical activity, and higher participation in physical activity than COMP participants (Hedge's g ≥ 0.5). The PROPEL program delivered during stroke rehabilitation shows promise for reducing barriers to exercise and increasing participation in physical activity after discharge. This study supports feasibility of a larger randomized trial to evaluate this program.

Robot-Assisted End-Effector-Based Stair Climbing for Cardiopulmonary Exercise Testing: Feasibility, Reliability, and Repeatability

Background

Neurological impairments can limit the implementation of conventional cardiopulmonary exercise testing (CPET) and cardiovascular training strategies. A promising approach to provoke cardiovascular stress while facilitating task-specific exercise in people with disabilities is feedback-controlled robot-assisted end-effector-based stair climbing (RASC). The aim of this study was to evaluate the feasibility, reliability, and repeatability of augmented RASC-based CPET in able-bodied subjects, with a view towards future research and applications in neurologically impaired populations.

Methods

Twenty able-bodied subjects performed a familiarisation session and 2 consecutive incremental CPETs using augmented RASC. Outcome measures focussed on standard cardiopulmonary performance parameters and on accuracy of work rate tracking (RMSE_P−root mean square error). Criteria for feasibility were cardiopulmonary responsiveness and technical implementation. Relative and absolute test-retest reliability were assessed by intraclass correlation coefficients (ICC), standard error of the measurement (SEM), and minimal detectable change (MDC). Mean differences, limits of agreement, and coefficients of variation (CoV) were estimated to assess repeatability.

Results

All criteria for feasibility were achieved. Mean V′O_2peak was 106±9% of predicted V′O_2max and mean HR_peak was 99±3% of predicted HR_max. 95% of the subjects achieved at least 1 criterion for V′O_2max, and the detection of the sub-maximal ventilatory thresholds was successful (ventilatory anaerobic threshold 100%, respiratory compensation point 90% of the subjects). Excellent reliability was found for peak cardiopulmonary outcome measures (ICC ≥ 0.890, SEM ≤ 0.60%, MDC ≤ 1.67%). Repeatability for the primary outcomes was good (CoV ≤ 0.12).

Conclusions

RASC-based CPET with feedback-guided exercise intensity demonstrated comparable or higher peak cardiopulmonary performance variables relative to predicted values, achieved the criteria for V′O_2max, and allowed determination of sub-maximal ventilatory thresholds. The reliability and repeatability were found to be high. There is potential for augmented RASC to be used for exercise testing and prescription in populations with neurological impairments who would benefit from repetitive task-specific training.

Cardiac autonomic dysfunction in chronic stroke women is attenuated after submaximal exercise test, as evaluated by linear and nonlinear analysis

Background

We evaluated cardiac autonomic modulation in women with chronic ischemic stroke (at least 4 years post-stroke) at rest and in response to submaximal exercise test.

Methods

Fourteen post-stroke women (S group) and 10 healthy women (C group) participated in this study. Autonomic modulation (using linear and nonlinear analysis), blood pressure and metabolic variables at rest were evaluated immediately after the exercise test and during the recovery period (20 min). All participants underwent submaximal exercise test on cycle ergometer with gas analysis.

Results

At rest, the S group displayed higher lactate concentration, systolic (SBP) and diastolic blood pressure (DBP) values when compared to C group. Furthermore, the S group had lower heart rate variability (HRV) in time domain (SDNN: S = 30 ± 5 vs. 40 ± 8 ms; rMSSD: S = 14 ± 2 vs. C = 34 ± 3 ms), decreased high frequency band of pulse interval (S = 8.4 ± 2 vs. 33.1 ± 9 %) and 2V pattern of symbolic analysis (S = 17.3 ± 1 vs. 30 ± 3 %) (both indicators of cardiac vagal modulation) when compared to C group. Immediately after exercise, S group presented higher values of lactate, SBP, DBP and double product when compared to C group, as well as decreased heart rate recovery (HRR) measured at the first, second and third minutes. At recovery time, all HRV parameters in time and frequency domains improved in the S group; however, HF band remained lower when compared to C group.

Conclusions

After the exercise test, women with chronic stroke presented reduced heart rate variability, reduced cardiac vagal modulation, as well as reduced HRR, while displayed an improvement of heart rate variability and cardiac vagal modulation when compared to their baseline. These results reinforce the importance of a physically active lifestyle for cardiovascular autonomic disorders observed in chronic stroke women.

Feasibility of cardiopulmonary exercise testing and training using a robotics-assisted tilt table in dependent-ambulatory stroke patients

Background

We evaluated the feasibility of an augmented robotics-assisted tilt table (RATT) for incremental cardiopulmonary exercise testing (CPET) and exercise training in dependent-ambulatory stroke patients.

Methods

Stroke patients (Functional Ambulation Category ≤ 3) underwent familiarization, an incremental exercise test (IET) and a constant load test (CLT) on separate days. A RATT equipped with force sensors in the thigh cuffs, a work rate estimation algorithm and real-time visual feedback to guide the exercise work rate was used. Feasibility assessment considered technical feasibility, patient tolerability, and cardiopulmonary responsiveness.

Results

Eight patients (4 female) aged 58.3 ± 9.2 years (mean ± SD) were recruited and all completed the study. For IETs, peak oxygen uptake (V'O_2peak), peak heart rate (HR_peak) and peak work rate (WR_peak) were 11.9 ± 4.0 ml/kg/min (45 % of predicted V'O_2max), 117 ± 32 beats/min (72 % of predicted HR_max) and 22.5 ± 13.0 W, respectively. Peak ratings of perceived exertion (RPE) were on the range "hard" to "very hard". All 8 patients reached their limit of functional capacity in terms of either their cardiopulmonary or neuromuscular performance.

A ventilatory threshold (VT) was identified in 7 patients and a respiratory compensation point (RCP) in 6 patients: mean V'O₂ at VT and RCP was 8.9 and 10.7 ml/kg/min, respectively, which represent 75 % (VT) and 85 % (RCP) of mean V'O_2peak. Incremental CPET provided sufficient information to satisfy the responsiveness criteria and identification of key outcomes in all 8 patients.

For CLTs, mean steady-state V'O₂ was 6.9 ml/kg/min (49 % of V'O₂ reserve), mean HR was 90 beats/min (56 % of HR_max), RPEs were > 2, and all patients maintained the active work rate for 10 min: these values meet recommended intensity levels for bouts of training.

Conclusions

The augmented RATT is deemed feasible for incremental cardiopulmonary exercise testing and exercise training in dependent-ambulatory stroke patients: the approach was found to be technically implementable, acceptable to the patients, and it showed substantial cardiopulmonary responsiveness. This work has clinical implications for patients with severe disability who otherwise are not able to be tested.

Cardiovascular Stress Induced by Whole-Body Vibration Exercise in Individuals With Chronic Stroke

BACKGROUND

Although whole-body vibration (WBV) has sparked tremendous research interest in neurorehabilitation, the cardiovascular responses to WBV in people with stroke remain unknown.

OBJECTIVE

The aim of this study was to determine the acute effects of different WBV protocols on oxygen consumption (V̇o2), heart rate (HR), rate of perceived exertion (RPE), blood pressure (BP), and rate-pressure product (RPP) during the performance of 6 different exercises among people with chronic stroke (time since onset ≥6 months).

DESIGN

A repeated-measures design was used.

METHODS

Each of the 48 participants experienced all 3 WBV protocols in separate sessions: (1) no WBV, (2) low-intensity WBV (peak acceleration=0.96 unit of gravity of Earth [g]), and (3) high-intensity WBV (1.61g). The order in which they encountered the WBV protocols was randomized, as was the order of exercises performed during each session. Oxygen consumption, HR, and RPE were measured throughout the study. Blood pressure and RPP were measured before and after each session.

RESULTS

Low-intensity and high-intensity WBV induced significantly higher V̇o2 by an average of 0.69 and 0.79 mL/kg/min, respectively, compared with the control condition. These protocols also increased HR by an average of 4 bpm. The 2 WBV protocols induced higher RPE than the control condition during static standing exercise only. Although the diastolic and systolic BP and RPP were increased at the end of each exercise session, the addition of WBV had no significant effect on these variables.

LIMITATIONS

The results are generalizable only to ambulatory and community-dwelling people with chronic stroke.

CONCLUSIONS

Addition of high- and low-intensity WBV significantly increased the V̇o2 and HR, but the increase was modest. Thus, WBV should not pose any substantial cardiovascular hazard in people with chronic stroke.

Integrating aerobic training within subacute stroke rehabilitation: a feasibility study

BACKGROUND

Aerobic activity positively affects patients recovering from stroke and is part of best practice guidelines, yet this evidence has not been translated to routine practice.

OBJECTIVE

The objective of this study was to evaluate the feasibility of a model of care that integrated aerobic training in an inpatient rehabilitation setting for patients in the subacute stage of stroke recovery. Key elements of the program were personalized training prescription based on submaximal test results and supervision within a group setting.

DESIGN

This was a prospective cohort study.

METHODS

Participants (N=78) completed submaximal exercise testing prior to enrollment, and the test results were used by their treating physical therapists for exercise prescription. Feasibility was evaluated using enrollment, class attendance, adherence to prescription, and participant perceptions.

RESULTS

Overall, 31 patients (40%) were referred to and completed the exercise program. Cardiac comorbidities were the main reason for nonreferral to the fitness group. Program attendance was 77%; scheduling conflicts were the primary barrier to participation. The majority of participants (63%) achieved 20 minutes of continuous exercise by the end of the program. No adverse events were reported, all participants felt they benefited from the program, and 80% of the participants expressed interest in continuing to exercise regularly after discharge.

LIMITATIONS

Cardiac comorbidities prevented enrollment in the program for 27% of the admitted patients, and strategies for inclusion in exercise programs in this population should be explored.

CONCLUSIONS

This individualized exercise program within a group delivery model was feasible; however, ensuring adequate aerobic targets were met was a challenge, and future work should focus on how best to include individuals with cardiac comorbidities.

Cardiopulmonary exercise testing early after stroke using feedback-controlled robotics-assisted treadmill exercise: test-retest reliability and repeatability

BACKGROUND

Exercise capacity is seriously reduced after stroke. While cardiopulmonary assessment and intervention strategies have been validated for the mildly and moderately impaired populations post-stroke, there is a lack of effective concepts for stroke survivors suffering from severe motor limitations. This study investigated the test-retest reliability and repeatability of cardiopulmonary exercise testing (CPET) using feedback-controlled robotics-assisted treadmill exercise (FC-RATE) in severely motor impaired individuals early after stroke.

METHODS

20 subjects (age 44-84 years, <6 month post-stroke) with severe motor limitations (Functional Ambulatory Classification 0-2) were selected for consecutive constant load testing (CLT) and incremental exercise testing (IET) within a powered exoskeleton, synchronised with a treadmill and a body weight support system. A manual human-in-the-loop feedback system was used to guide individual work rate levels. Outcome variables focussed on standard cardiopulmonary performance parameters. Relative and absolute test-retest reliability were assessed by intraclass correlation coefficients (ICC), standard error of the measurement (SEM), and minimal detectable change (MDC). Mean difference, limits of agreement, and coefficient of variation (CoV) were estimated to assess repeatability.

RESULTS

Peak performance parameters during IET yielded good to excellent relative reliability: absolute peak oxygen uptake (ICC =0.82), relative peak oxygen uptake (ICC =0.72), peak work rate (ICC =0.91), peak heart rate (ICC =0.80), absolute gas exchange threshold (ICC =0.91), relative gas exchange threshold (ICC =0.88), oxygen cost of work (ICC =0.87), oxygen pulse at peak oxygen uptake (ICC =0.92), ventilation rate versus carbon dioxide output slope (ICC =0.78). For these variables, SEM was 4-13%, MDC 12-36%, and CoV 0.10-0.36. CLT revealed high mean differences and insufficient test-retest reliability for all variables studied.

CONCLUSIONS

This study presents first evidence on reliability and repeatability for CPET in severely motor impaired individuals early after stroke using a feedback-controlled robotics-assisted treadmill. The results demonstrate good to excellent test-retest reliability and appropriate repeatability for the most important peak cardiopulmonary performance parameters. These findings have important implications for the design and implementation of cardiovascular exercise interventions in severely impaired populations. Future research needs to develop advanced control strategies to enable the true limit of functional exercise capacity to be reached and to further assess test-retest reliability and repeatability in larger samples.