Modified total-body recumbent stepper exercise test for assessing peak oxygen consumption in people with chronic stroke

Results of a feasibility and initial efficacy clinical trial of a high-intensity interval training program using adaptive equipment in persons with multiple sclerosis who have walking disability

BACKGROUND

High intensity interval training (HIIT) has been identified as potential stimulus for eliciting health-promoting physical activity in an efficient manner among persons with multiple sclerosis (MS). The current study aimed to examine the feasibility and initial efficacy of a 12-week HIIT program using a recumbent stepper (RSTEP) in persons with MS who have walking disability. Feasibility outcomes of interest included process (i.e., recruitment, adherence, and retention rates), resource (i.e., time and monetary costs), management (i.e., data management and safety reporting assessment), and science (i.e., safety, burden, and treatment effect assessment). We hypothesized that 12-weeks of HIIT will be feasible via meeting a priori benchmarks in process, resource, management, and scientific outcomes. The efficacy outcomes of interest included changes in aerobic fitness, physical activity, walking, upper arm function, cognition, fatigue, and depressive symptoms. We hypothesized that 12 weeks of HIIT would result in improvements in aerobic capacity, walking, upper arm function, cognition, fatigue, and depression.

METHODS

A pre-post clinical trial design was applied. Participants (N = 16) were recruited and enrolled in the 12-week RSTEP HIIT program who met the following inclusion criteria: age ≥18 years, self-reported diagnosis of MS, Patient Determined Disability Steps scale score 3.0-7.0, relapse free in past 30 days, willing to visit a University Laboratory for study protocol, asymptomatic status for maximal exercise testing, physician approval, and a self-reported ability to speak, read, and understand English. Measures of efficacy outcomes of interest included Six Minute Walk Test (6MW), Timed 25 Foot Walk Test (T25FW), the Brief International Cognitive Assessment in MS (BICAMS), 9-hole peg test (9-HPT), Expanded Disability Status Scale (EDSS), Fatigue Severity Survey (FSS), Hospital Anxiety and Depression Scale (HADS), Godin Leisure Time Exercise Questionnaire (GLTEQ), Multiple Sclerosis Walking Scale-12 (MSWS-12). Participants completed a graded maximal exercise test for measuring aerobic fitness (VO2peak) and prescription of exercise throughout the intervention. All outcomes were measured at baseline, mid-point (6-weeks), and post-intervention (12-weeks). The intervention involved 12 weeks of supervised, individualized HIIT sessions two times per week using RSTEP. The individual HIIT sessions included 10 cycles of 60 s intervals at the work rate associated with 90 % VO2peak followed by 60 s of active recovery intervals, totaling 20 minutes plus 5-minute warm-up and cool-down periods. Process, resources, management, and scientific feasibility outcomes were examined using descriptive statistics, percentage, and frequency analyses. The efficacy of the intervention was assessed using a 1-factor (Time), repeated measure analysis of variance to identify significant changes over time.

RESULTS

Fourteen of 16 participants were retained throughout the full study period and adherence with prescribed exercise sessions was 97 %. Twenty-three staff were comprehensively trained across two sites. There was only one adverse event reported that did not impact participation in the study and overall mean satisfaction rating with the program among participants was 4.7/5. There were statistically significant changes in cognitive processing speed (p = 0.002), GLTEQ (p = 0.005), and MSWS-12 (p = 0.04), but not the other outcomes of fitness, arm function, and walking. Of note, there were large effect sizes noted for peak power output (d = 1.10) and FSS (d = 1.05) despite the lack of statistically significant changes CONCLUSION: Feasibility of a 12-week individualized RSTEP HIIT program was established and participants significantly improved on measures of cognition, physical activity, and walking.

Feasibility of a Recumbent Stepper for Short-Interval, Low-Volume High-Intensity Interval Exercise in Stroke

BACKGROUND AND PURPOSE

Studies investigating high-intensity interval exercise (HIIE) in stroke typically emphasize treadmill training. However, a literature review suggested that seated devices such as a recumbent stepper or cycle offer a promising alternative for HIIE since exercise can be prescribed using peak power output (PPO). Therefore, this would give health care professionals the ability to monitor and adapt power output for the target heart rate range. The purpose of this secondary analysis was to examine the feasibility of prescribing short-interval, low-volume HIIE using PPO in chronic stroke.

METHODS

We used several methods to test feasibility: (1)Acceptability: Measured by the percentage of participants who completed the entire HIIE protocol; (2) Implementation was assessed by the number of reported cardiac or serious adverse events during submaximal exercise testing and HIIE and the average percentage of participants reaching vigorous intensity, defined by the American College of Sports Medicine as at least 77% of age-predicted maximal heart rate (HR max ).

RESULTS

Data were available for 28 participants who were 32.2 (17.2) months post-stroke and 61.4 (11.9) years of age. Twenty-eight participants completed HIIE per protocol. No cardiac or serious adverse events occurred during the submaximal exercise test or during HIIE. The rapid switching between HIIE and recovery showed no evidence of blood pressure reaching unsafe thresholds. Average intensity during HIIE reached 76.8% HR max , which is slightly below the target of 77.0%.

DISCUSSION AND CONCLUSIONS

A single bout of short-interval, low-volume HIIE, prescribed using PPO, was feasible in chronic stroke.

Video Abstract : Available for more insights from the authors (Supplemental Digital Content, Video, available at: http://links.lww.com/JNPT/A474 ).

A 3-minute recumbent stepper test in chronic stroke

BACKGROUND

Persons with stroke often have difficulty achieving target heart rate (HR) during graded exercise testing (GXT), which is known to limit test sensitivity for detecting clinically relevant cardiac conditions. A novel Recumbent Stepper 3-minute (RS 3Min) "all out" test may increase sensitivity of stress testing after stroke.

OBJECTIVE

To determine the feasibility of adding the RS 3Min test after GXT among persons after stroke.

DESIGN

A within-participant, nonrandomized, repeated measures design.

SETTING

Rehabilitation research laboratory and cardiovascular stress laboratory PARTICIPANTS: Fifteen participants with chronic stroke (56.7 ± 9.6 years; 6.4 ± 4.3 years post stroke; 8 male).

INTERVENTIONS

All participants randomly completed (1) a symptom-limited treadmill GXT and (2) a symptom-limited RS GXT followed by RS 3Min critical power test.

MAIN OUTCOME MEASURES

HR, ratings of perceived exertion, oxygen consumption, respiratory exchange ratio, and power output measured continuously during each test. Blood pressure measured every 2 minutes and or immediately post exercise. P value set at p < .05 from omnibus test for a significant difference among protocols.

RESULTS

The RS 3Min test had a significantly higher rate of achieving target HR compared to the RS GXT (9/14 vs 4/14, p = .02) and was not significantly different from the treadmill GXT (9/14 vs 5/14, p = .09). Minimum power output during the RS 3Min was significantly higher than peak power output during the RS GXT (110 ± 41 W vs. 84 ± 22 W, p = .02) with 12/15 participants reaching a VO2 plateau.

CONCLUSIONS

Although additional studies with randomized designs are needed, a novel RS 3Min "all out" test appears to be a promising method for enhancing test sensitivity in cardiovascular screening after stroke, while providing a potentially valid measure of critical power.

Investigating the Effect of Novel Gamified Stepper on Lower Limb Biomechanics in Seated Healthy Subjects

The present study introduces a new gamified stepper device designed for bilateral lower limb rehabilitation, which is combined with a 3-D exergame. To the best of our knowledge, this is the initial study to utilize the stepping exercise for seated lower limb rehabilitation. The device comprises a stepping mechanism and a magnetic encoder. The modified stepper facilitates the bilateral training in the lower limb within its workspace. The magnetic encoder provides real-time rotational angle data during the exercise. A task-specific exergame platform was created and integrated with the device to enhance user compliance and engagement with the exercise. Experiments were conducted with ten healthy individuals with no history of lower limb injury to evaluate the system's feasibility for providing bilateral training and the effectiveness of the exergame platform. Participants were asked to perform bilateral lower limb exercise with a metronome and gamified stepper device in a seated position. Lower limb range of motion (ROM) and EMG activations were recorded during the exercises. The results indicate that the device was capable of providing cyclical ROM training with reduced muscle activation of the lower limb, and the exergame platform increased motivation to continue the exercises. This study can serve as the foundation for developing a robotic version of the proposed stepper device.

Feasibility of Seated Stepping and Handshaking as a Cardiopulmonary Exercise Testing: A Pilot Study

Cardiopulmonary function is usually assessed by cardiopulmonary exercise testing (CPX) using a cycle ergometer (CE-CPX) or a treadmill, which is difficult in patients with lower extremity motor dysfunction. A stepping and handshaking (SHS) exercise has been developed that can be performed safely and easily while sitting on a chair. This study compared peak oxygen uptake (peak V.O2) between CE-CPX and SHS-CPX in healthy adults and investigated the safety and validity of SHS-CPX. Twenty young adults (mean age 27.8 ± 4.4 years) were randomly assigned to perform CE-CPX or SHS-CPX, with the other test to follow 1–2 weeks later. The peak V.O2, respiratory exchange ratio (RER), peak heart rate, blood pressure, and test completion time were compared between CE-CPX and SHS-CPX. All subjects completed the examination and met the criteria for peak V.O2. SHS-CPX and CE-CPX showed a strong correlation with peak V.O2 (r = 0.85, p < 0.0001). The peak V.O2 (40.4 ± 11.3 mL/min/kg vs. 28.9 ± 8.0 mL/min/kg), peak heart rate (190.6 ± 8.9 bpm vs. 172.1 ± 12.6 bpm), and test completion time (1052.8 ± 143.7 s vs. 609.1 ± 96.2 s) were significantly lower in the SHS-CPX (p < 0.0001). There were no adverse events. The peak V.O2 with SHS-CPX was equivalent to about 70% of that with CE-CPX despite the exercise being performed in a sitting position, suggesting its suitability as a submaximal exercise test.

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.

Quantification of Tissue Oxygen Saturation in the Vastus Lateralis Muscle of Chronic Stroke Survivors during a Graded Exercise Test

Purpose

This study examined tissue oxygen saturation (StO2) of the vastus lateralis (VL) muscles of chronic stroke survivors during a graded exercise test (GXT). We hypothesized the reduction in StO2 will be blunted in the paretic vs. non-paretic VL during a maximum-effort GXT.

Methods

Chronic stroke survivors performed a GXT and StO2 of the VL in each leg was measured using near infrared spectroscopy. Twenty-six stroke survivors performed a GXT.

Results

At rest, there was no difference in StO2 between the paretic and non-paretic VL (65±9% vs. 68±7%, respectively, p=0.32). The maximum change in StO2 from rest during the GXT was greater in the non-paretic vs. the paretic VL (-16±14% vs. -9±10%, respectively, p<0.001). The magnitude of the oxygen resaturation response was also greater in the non-paretic vs. the paretic VL (29±23% vs. 18±15%, respectively, p<0.001). VO2 Peak was associated with the magnitude of the VL StO2 change during (r2=0.54, p<0.0001) and after (r2=0.56, p<0.001) the GXT.

Conclusions

During a GXT there is a blunted oxygen desaturation response in the paretic vs. the non-paretic VL of chronic stroke survivors. In the paretic VL there was a positive correlation between the oxygen desaturation response during the GXT and VO2 Peak.

Intensity matters: protocol for a randomized controlled trial exercise intervention for individuals with chronic stroke

Rationale

Cardiovascular exercise is an effective method to improve cardiovascular health outcomes, but also promote neuroplasticity during stroke recovery. Moderate-intensity continuous cardiovascular training (MICT) is an integral part of stroke rehabilitation, yet it may remain a challenge to exercise at sufficiently high intensities to produce beneficial adaptations to neuroplasticity. High-intensity interval training (HIIT) could provide a viable alternative to achieve higher intensities of exercise by using shorter bouts of intense exercise interspersed with periods of recovery.

Methods and design

This is a two-arm, parallel-group multi-site RCT conducted at the Jewish Rehabilitation Hospital (Laval, Québec, Canada) and McMaster University (Hamilton, Ontario, Canada). Eighty participants with chronic stroke will be recruited at both sites and will be randomly allocated into a HIIT or MICT individualized exercise program on a recumbent stepper, 3 days per week for 12 weeks. Outcomes will be assessed at baseline, at 12 weeks post-intervention, and at an 8-week follow-up.

Outcomes

The primary outcome is corticospinal excitability, a neuroplasticity marker in brain motor networks, assessed with transcranial magnetic stimulation (TMS). We will also examine additional markers of neuroplasticity, measures of cardiovascular health, motor function, and psychosocial responses to training.

Discussion

This trial will contribute novel insights into the effectiveness of HIIT to promote neuroplasticity in individuals with chronic stroke.

Trial registration

ClinicalTrials.govNCT03614585. Registered on 3 August 2018

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06359-w.

Cardiopulmonary Exercise Testing in Stroke Rehabilitation: Benefits and Clinical Utility Perceived by Physiotherapists and Individuals with Stroke

Purpose: The purpose of this study was to understand the perceived benefits and clinical utility of cardiopulmonary exercise testing (CPET) from the perspectives of physiotherapists and patients and to explore the factors that influence adopting CPET in a stroke rehabilitation setting. Method: A qualitative descriptive study was conducted. Physiotherapists (n = 6) participated in a focus group to discuss the use of CPET in practice. Patients (n = 8) who had completed CPET during stroke rehabilitation participated in a semi-structured interview to explore their experiences. Thematic analysis was performed. Results: CPET increased the physiotherapists' confidence in prescribing exercise, especially for medically complex patients. Ongoing medical management early post-stroke was a barrier to referral. Physiotherapists expressed decreased confidence in interpreting test results. Consultation with local experts facilitated the use of CPET. Patients described how CPET increased their confidence to participate in exercise. They desired more information before and after CPET to better understand the purpose and results and their relation to their rehabilitation goals. Conclusions: Both physiotherapists and patients described the benefit of having CPET available to support them as they participated in exercise in a stroke rehabilitation setting. Physiotherapists would benefit from having educational tools to support their interpretation and application of test results, and patients would benefit from improved communication and education to support their understanding of the relevance of CPET to their rehabilitation goals. Future research should explore these findings in other stroke rehabilitation settings.

Reliability of a recumbent stepper submaximal exercise test after traumatic brain injury

Purpose: To determine the test-retest reliability of a total body recumbent stepper (TBRS) submaximal exercise test and to examine its relationship with other measures throughout the International Classification of Functioning that are indicative of overall health in individuals with traumatic brain injury (TBI).Methods: Twenty-three ambulatory individuals with severe, chronic (>6 mos) TBI completed a TBRS submaximal exercise test, 6-minute walk test (6MWT), and Mayo Portland Adaptability Inventory (MPAI-4) at initial testing. A repeat TBRS submaximal exercise test was conducted 4-7 days later. Estimated peak oxygen consumption (VO₂) was calculated from the TBRS submaximal exercise test using the VO₂ prediction equation. Average daily step count was collected by an activity monitor for the 4-7-day period between tests.Results: Test-retest reliability was good (ICC_3,1 = 0.79, p < .001). The difference between the tests was 0.46 ml・kg^-1・min^-1 which was not statistically different. Neither the 6MWT distance nor gait speed are related to the TBRS-estimated peak VO₂. The MPAI-4 total score and adjustment subscale each had a fair relationship with the TBRS-estimated peak VO₂ (r = -0.41, p = .05; rs = -0.41, p = .05, respectively).Conclusion: These data suggest that the TBRS submaximal exercise test may be a reliable measure to estimate peak VO₂ in ambulatory adults with chronic severe TBI.

Task-Oriented Circuit Training as an Alternative to Ergometer-Type Aerobic Exercise Training after Stroke

Moderate-intensity aerobic exercise training is an important treatment strategy to enhance functional recovery and decrease cardiometabolic risk factors after stroke. However, stroke related impairments limit access to ergometer-type exercise. The aims of the current study were (1) to evaluate whether our task-oriented circuit training protocol (intermittent functional training; IFT) could be used to sustain moderate-intensity aerobic workloads over a 10-week intervention period, and (2) to investigate its preliminary effects on cardiorespiratory fitness and metabolic profiles compared to constant-load ergometer-type exercise (CET). Forty chronic hemiparetic stroke survivors were randomized to receive 30 sessions of IFT or CET over ten weeks. Similar proportions of participants were randomized to IFT (7/19) and CET (9/18) sustained workloads associated with moderate-intensity aerobic exercise over the study period (p = 0.515). However, CET was associated with more substantial changes in maximal oxygen uptake (MD = 2.79 mL min⁻¹ kg⁻¹ CI: 0.84 to 4.74) compared to IFT (MD = 0.62 mL min⁻¹ kg⁻¹ CI: −0.38 to 1.62). Pre to post changes in C-reactive protein (−0.9 mg/L; p =0.017), short-term glycemia (+14.7 µmol/L; p = 0.026), and resting whole-body carbohydrate oxidation (+24.2 mg min⁻¹; p = 0.046) were observed when considering both groups together. Accordingly, IFT can replicate the aerobic intensities sustained during traditional ergometer-type exercise training. More work is needed to evaluate the dose–response effects of such task-oriented circuit training protocols on secondary prevention targets across the continuum of stroke recovery.

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.

An Endurance-Dominated Exercise Program Improves Maximum Oxygen Consumption, Ground Reaction Forces, and Muscle Activities in Patients With Moderate Diabetic Neuropathy

Background

The prevalence of diabetes worldwide is predicted to increase from 2.8% in 2000 to 4.4% in 2030. Diabetic neuropathy (DN) is associated with damage to nerve glial cells, their axons, and endothelial cells leading to impaired function and mobility.

Objective

We aimed to examine the effects of an endurance-dominated exercise program on maximum oxygen consumption (VO₂max), ground reaction forces, and muscle activities during walking in patients with moderate DN.

Methods

Sixty male and female individuals aged 45–65 years with DN were randomly assigned to an intervention (IG, n = 30) or a waiting control (CON, n = 30) group. The research protocol of this study was registered with the Local Clinical Trial Organization (IRCT20200201046326N1). IG conducted an endurance-dominated exercise program including exercises on a bike ergometer and gait therapy. The progressive intervention program lasted 12 weeks with three sessions per week, each 40–55 min. CON received the same treatment as IG after the post-tests. Pre- and post-training, VO₂max was tested during a graded exercise test using spiroergometry. In addition, ground reaction forces and lower limbs muscle activities were recorded while walking at a constant speed of ∼1 m/s.

Results

No statistically significant baseline between group differences was observed for all analyzed variables. Significant group-by-time interactions were found for VO₂max (p < 0.001; d = 1.22). The post-hoc test revealed a significant increase in IG (p < 0.001; d = 1.88) but not CON. Significant group-by-time interactions were observed for peak lateral and vertical ground reaction forces during heel contact and peak vertical ground reaction force during push-off (p = 0.001–0.037; d = 0.56–1.53). For IG, post-hoc analyses showed decreases in peak lateral (p < 0.001; d = 1.33) and vertical (p = 0.004; d = 0.55) ground reaction forces during heel contact and increases in peak vertical ground reaction force during push-off (p < 0.001; d = 0.92). In terms of muscle activity, significant group-by-time interactions were found for vastus lateralis and gluteus medius during the loading phase and for vastus medialis during the mid-stance phase, and gastrocnemius medialis during the push-off phase (p = 0.001–0.044; d = 0.54–0.81). Post-hoc tests indicated significant intervention-related increases in vastus lateralis (p = 0.001; d = 1.08) and gluteus medius (p = 0.008; d = 0.67) during the loading phase and vastus medialis activity during mid-stance (p = 0.001; d = 0.86). In addition, post-hoc tests showed decreases in gastrocnemius medialis during the push-off phase in IG only (p < 0.001; d = 1.28).

Conclusions

This study demonstrated that an endurance-dominated exercise program has the potential to improve VO₂max and diabetes-related abnormal gait in patients with DN. The observed decreases in peak vertical ground reaction force during the heel contact of walking could be due to increased vastus lateralis and gluteus medius activities during the loading phase. Accordingly, we recommend to implement endurance-dominated exercise programs in type 2 diabetic patients because it is feasible, safe and effective by improving aerobic capacity and gait characteristics.

Optimizing Recruitment Strategies and Physician Engagement for Stroke Recovery Research

BACKGROUND AND PURPOSE

A major challenge for stroke rehabilitation and recovery research is the recruitment and retention of participants. Our prior challenges and successes have influenced our team to rethink our approach and the potential for large-scale stroke recruitment.

SUMMARY OF KEY POINTS

In this special interest article, we highlight how the adoption and implementation of recruitment strategies such as physician engagement and a streamlined "customer service" approach helped us improve our enrollment and maximize efficiency. Another positive outcome of enrollment was increased representation of those who identify as underrepresented minority or live in rural areas.

RECOMMENDATIONS FOR CLINICAL PRACTICE

Rethinking our recruitment processes and infrastructure allowed for greater interprofessional interactions, minimal burden for our stroke physician team members, and maximized enrollment into our stroke studies.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A324).

Feasibility and initial efficacy of a high-intensity interval training program using adaptive equipment in persons with multiple sclerosis who have walking disability: study protocol for a single-group, feasibility trial

Background

There is considerable evidence for the efficacy of moderate-intensity continuous exercise benefitting clinically relevant outcomes in persons with multiple sclerosis (MS). However, persons with MS who have walking disability (pwMS-wd) are severely deconditioned and may achieve superior benefits by engaging in high-intensity interval training (HIIT), especially while utilizing adaptive equipment, such as recumbent arm/leg stepping (RSTEP). The proposed study will assess the feasibility of a 12-week, RSTEP HIIT program in pwMS-wd. The secondary aim will examine changes in aerobic fitness, physical activity, ambulation, upper arm function, cognition, fatigue, and depression as clinically relevant efficacy outcomes following the 12-week, RSTEP HIIT intervention.

Methods

The study will recruit 15 pwMS-wd. Feasibility will be measured via process, resource, management, and scientific outcomes throughout the entirety of the research study. The secondary, clinically relevant outcomes will consist of a neurological exam, aerobic capacity, physical activity, ambulation, cognition, upper arm function, fatigue, and depression. Outcomes will be assessed at baseline (T1), midpoint (T2, following 6 weeks), and post-intervention (T3, following 12 weeks). The intervention will involve 12 weeks of supervised, individualized HIIT sessions two to three times per week. The individual HIIT sessions will each involve 10 cycles of 60-s intervals at the wattage associated with 90% VO_2peak followed by 60 s of active recovery intervals at 15 W, totaling 20 min in length plus 5-min warm-up and cool-down periods.

Discussion

The feasibility design of the proposed study will provide experience and preliminary data for advancing towards a proof-of-concept study comparing HIIT to moderate-intensity continuous RSTEP for improving clinically relevant outcomes in a randomized control trial design. The results will be disseminated via manuscripts for publication and a report for distribution among the National Multiple Sclerosis Society.

Trial registration

ClinicalTrials.gov NCT04416243. Retrospectively registered on June 4, 2020

Determining Maximal Tolerable Aerobic Training Intensity in the Acute Phase after Stroke: a Novel Dose Ranging Trial Protocol

INTRODUCTION

There is strong evidence that cardiorespiratory fitness (CRF) training improves fitness and mobility after stroke. Despite the large number of studies, the most efficacious dose is yet to be determined. Furthermore, the safety of early post-stroke training, while theoretically beneficial, remains uncertain. The aim of this study is to determine the maximum safe and tolerable intensity of CRF training early post-stroke.

METHODS

This is a stratified (low to moderate exercise capacity), Phase I, 5+5 dose ranging trial protocol. Participants will be recruited within one month post-stroke and stratified by their exercise-capacity (i.e. low and moderate capacity). Cohorts of five participants will perform 12 interval-based training sessions for four-weeks at a pre-determined target-intensity. The intensity will increase in each consecutive cohort, in each stratum according to pre-defined rules until the maximum safe and tolerable intensity is reached, as determined by the occurrence of dose-limiting events and occurrence of adverse events. Dose-limiting events are defined as symptoms indicative of over-training including pain and inability to perform usual activities.

STUDY OUTCOME

Maximum safe and tolerable intensity of CRF training in stroke survivors with low and moderate exercise capacity.

DISCUSSION

This study is a first step in the systematic development of a CRF training intervention. We believe similar dose ranging designs may be useful for development of other rehabilitation interventions in different study populations.

The test-retest reliability of individualized VO2peak test modalities in people with spinal cord injury undergoing rehabilitation

STUDY DESIGN

Test-retest study.

OBJECTIVE

To describe the test-retest reliability of an individualized approach for peak oxygen uptake (VO₂peak) testing in a clinical context, accommodating inpatients with heterogeneous levels of physical functioning.

SETTING

Inpatient rehabilitation.

METHOD

Test-retest on two types of devices (recumbent stepper and arm-crank ergometer) with two predefined protocols of varying load increments on each device. No participants performed all four test modalities. VO₂peak, respiratory exchange ratio (RER), peak workload, and the reason for termination were reported. Of 23 participants included, 21 completed the test-retest procedure. Participants were inpatients, ≥18 years, who sustained a spinal cord injury (SCI) within the last 12 months at the time of admission. The median age was 52 years and 74% were male. Median time since injury at the time of the first test (T1) was 5.5 months. Seventeen were classified as American Spinal Injury Association Impairment Scale D. Intraclass correlation coefficients (ICC) and Bland-Altman plots for VO₂peak was calculated to determine intra- and intertester reliability of VO₂peak.

RESULTS

Mean VO₂peak obtained at T1 was 1.91 L/min (95%CI: 1.31-2.51); 1.26 L/min and 2.69 L/min for the recumbent stepper protocols; 0.61 L/min and 1.39 L/min for the arm-crank ergometer protocols. ICC for intra- and intertester reliability was 0.997 (95%CI: 0.986-0.999) and 0.994 (95%CI: 0.978-0.998) respectively. Bland-Altman plots showed a mean difference of -0.005 (SD 0,12) for overall test-retest.

CONCLUSION

Test-retest reliability was high. Mean VO₂peak at discharge from rehabilitation was higher than previously reported and individualized test modalities seemed to yield more optimal results in a heterogenous and representative sample during rehabilitation.

Application of stepper in cardiopulmonary exercise test for patients with hemiplegia

A method to perform exercise testing for patients with hemiplegia is unavailable though over half of them have cardio-pulmonary disorders. We aimed to assess the reliability and validity of using a stepper in cardiopulmonary exercise testing (CPET) in this population.14 stroke patients with hemiplegia who failed to ride the stationary bike were included. Exclusion criteria included manual muscle strength ≦1 in the lower extremity, and conventional contraindications of CPET. They underwent CPET twice by using a stepper to evaluate test-retest reliability and validity. Additionally, 10 healthy participants underwent CPET twice on the cycle ergometer and stepper respectively.In the test-retest, the ratio of two-time difference to mean was 5.0, 3, 11.3 and 12.0% on average for peak oxygen consumption, peak heart rate (HR), anaerobic threshold and minute ventilation - carbonic dioxide production slope respectively. Cronbach's alpha coefficient of peak oxygen consumption and anaerobic threshold were 0.992 and 0.919. In the stepper exercise testing of the hemiplegic participants, the ratio of peak HR to age-predicted maximal HR was 75% on average. Peak respiratory exchange ratio (mean ± standard deviation = 1.17 ± 0.08) was not different from that of healthy controls (1.21 ± 0.09). Notably, VO2 trajectory in relation to work rate is nonlinear and different in the rest-retest.This is the first research to study CPET variables in detail using stepper in patients with hemiplegia. CPET variables associated with peak are valid and reliable; nonetheless, those with sub-maximum are not. The study provides a method to do exercise testing for the patients with hemiplegia and its notice in application.

Cardiovascular disease risk is associated with middle cerebral artery blood flow velocity in older adults

Purpose

The aim of this study was to evaluate the relationship of cardiovascular disease (CVD) on middle cerebral blood flow velocity (MCAv) at rest and during exercise. A secondary aim was to explore the relationship between MCAv and 1) the presence of white matter lesions and 2) cognitive function.

Methods

We recruited individuals who were cognitively normal older adults. CVD risk was assessed by the Pooled Cohort atherosclerotic cardiovascular disease (ASCVD) risk score. Transcranial Doppler ultrasound measured middle cerebral artery at rest and during a bout of moderate intensity exercise. We quantified white matter lesions from MRI and cognitive function outcomes included executive function, language, processing speed, and attention.

Results

Seventy-two participants 70.1 ± 4.7 years of age completed the study protocol. ASCVD risk score was significantly associated with resting and exercise MCAv (p<0.01) but not associated with white matter lesions (p>0.468). We observed a significant association between resting and exercise MCAv and language processing (p=0.010) but not other cognitive domains.

Conclusion

In cognitively normal older adults, higher ASCVD risk score was associated with blunted resting and exercise MCAv and with lower language processing performance. These results highlight the need for CVD risk management to maintain optimal brain health.

Health promotion and cardiovascular risk reduction in people with spinal cord injury: physical activity, healthy diet and maintenance after discharge- protocol for a prospective national cohort study and a preintervention- postintervention study

INTRODUCTION

Spinal cord injury (SCI) predisposes those who suffer from it to physical inactivity and weight gain; consequently, death due to cardiovascular diseases is more frequent among people with SCI than in the general population. The literature documents a consensus about an interdisciplinary multimodal approach for the prevention and treatment of cardiovascular risk factors including overweight and obesity in people with SCI, focusing on diet, physical activity (PA) and behavioural interventions. This study will investigate implementation of recommendations from a recent clinical practice guideline for identification and management of cardiometabolic risk after SCI through multimodal patient education in a subacute clinical setting.

METHODS AND ANALYSIS

All patients who are aged 18 years or older with an SCI within the previous 12 months and admitted to highly specialised rehabilitation are included, regardless of SCI aetiology or neurological level. A primary study designed as a controlled, pragmatic, preintervention- postintervention study with 6-month follow-up evaluates the effect of the clinical intervention; a prospective national cohort study on body mass index (BMI) serves as a historical control. The intervention consists of a standardised approach to patient education about cardiovascular risk factors, PA and a healthy diet that begins at the outset of primary SCI rehabilitation and is integrated into existing settings and workflows. Outcome measures are collected at admission, discharge and 6 months after discharge and include peak oxygen uptake (VO2peak) (primary outcome), BMI, body composition, metabolic profile, neurological status, level of functioning, depression, quality of life, objective PA (accelerometry), self-reported PA, self-assessed PA ability, shared decision making, and dietary habits. Test-retest reliability of four VO2peak test protocols are investigated, as is test-retest reliability of a multisensor accelerometer in a rehabilitation setting.

ETHICS AND DISSEMINATION

The project is approved by the Committees on Health Research Ethics in the Capital Region of Denmark on 10 July 2018 (Journal-nr.: H-18018325). The principal investigator obtains informed consent from all participants. The interventions in the project are closely related to existing rehabilitation care, and the risk of pain and discomfort is considered modest. Any unintended events related to the elements of the intervention are reported, according to existing regional procedures. Data are stored in a secure web-based database (Redcap). The primary study and prospective cohort study are registered at Clinicaltrials.gov. Positive and negative results will be submitted to relevant scientific journals related to SCI for publication. Important protocol modifications are reported to the Committees on Health Research Ethics in the Capital Region of Denmark.

TRIAL REGISTRATION NUMBERS

NCT03689023 and NCT03369080.

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.

Oxygen Cost During Mobility Tasks and Its Relationship to Fatigue in Progressive Multiple Sclerosis

OBJECTIVE

To compare the oxygen costs of mobility tasks between individuals with progressive multiple sclerosis (MS) using walking aids and matched controls and to determine whether oxygen cost predicted fatigue.

DESIGN

Cross-sectional descriptive.

SETTING

A rehabilitation research laboratory.

PARTICIPANTS

A total of 14 adults with progressive MS (mean age ± SD [y], 54.07±8.46) using walking aids and 8 age- and sex-matched controls without MS (N=22).

INTERVENTIONS

Participants performed 5 mobility tasks (rolling in bed, lying to sitting, sitting to standing, walking, climbing steps) wearing a portable metabolic cart.

MAIN OUTCOME MEASURES

Oxygen consumption (V˙o₂) during mobility tasks, maximal V˙o₂ during graded maximal exercise test, perceived exertion, and task-induced fatigue were measured on a visual analog scale before and after mobility tasks.

RESULTS

People with progressive MS had significantly higher oxygen cost in all tasks compared to controls (P<.05): climbing steps (3.60 times more in MS), rolling in bed (3.53), walking (3.10), lying to sitting (2.50), and sitting to standing (1.82). There was a strong, positive correlation between task-induced fatigue and oxygen cost of walking, (ρ [13]=0.626, P=.022).

CONCLUSIONS

People with progressive MS used 2.81 times more energy on average for mobility tasks compared to controls. People with progressive MS experienced accumulation of oxygen cost, fatigue, and exertion when repeating tasks and higher oxygen cost during walking was related to greater perception of fatigue. Our findings suggest that rehabilitation interventions that increase endurance during functional tasks could help reduce fatigue in people with progressive MS who use walking aids.

Prolonged cortical silent period is related to poor fitness and fatigue, but not tumor necrosis factor, in Multiple Sclerosis

OBJECTIVE

Poor fitness among people with Multiple Sclerosis (MS) aggravates disease symptoms. Whether low fitness levels accompany brain functioning changes is unknown.

METHODS

MS patients (n = 82) completed a graded maximal exercise test, blood was drawn, and transcranial magnetic stimulation determined resting and active motor thresholds, motor evoked potential latency, and cortical silent period (CSP).

RESULTS

Sixty-two percent of participants had fitness levels ranked below 10th percentile. Fitness was not associated with disability measured using the Expanded Disability Status Scale (EDSS). Regression analyses revealed that, cardiorespiratory fitness, when controlling for disease demographics, contributed 23.7% (p < 0.001) to the model explaining variance in CSP. Regression analysis using cardiorespiratory fitness and CSP as predictors showed that CSP alone explained 19.9% of variance in subjective fatigue (p = 0.002). Tumor necrosis factor was not associated with any variable.

CONCLUSION

Low fitness was associated with longer CSP in MS. Longer CSP was, in turn, related to greater MS fatigue.

SIGNIFICANCE

MS patients had extremely low levels of cardiorespiratory fitness. Poor fitness predicted longer CSP, a marker of greater intracortical inhibition, which was linked to MS fatigue. Future research should examine whether aerobic training could shorten CSP and potentially lessen inhibition of cortical networks.

Blunted cerebrovascular response is associated with elevated beta-amyloid

The goal of this study was to explore the association of beta-amyloid accumulation and cerebrovascular response (CVR) in cognitively normal older adults. Beta-amyloid accumulation was characterized with [18F] Florbetapir positron emission tomography scans. CVR was calculated as middle cerebral artery blood flow velocity change from rest to moderate intensity exercise. We found that individuals with elevated beta-amyloid aggregation had a blunted CVR ( n = 25, age 70.1 ± 4.8; 3.3 ± 3.7 cm/s) compared to non-elevated individuals ( n = 45, age 72.0 ± 4.9; 7.2 ± 5.0 cm/s, p < 0.001). Further, greater beta-amyloid burden was linearly associated with less CVR across all participants (b = -11.7, p < 0.001). Greater CVR and less beta-amyloid burden were associated with processing speed ( p < 0.05). This study is the first to show that CVR from rest to exercise is blunted across increased global beta-amyloid burden.

The Post Ischaemic Stroke Cardiovascular Exercise Study: Protocol for a randomised controlled trial of fitness training for brain health

INTRODUCTION

Compared to healthy individuals, stroke patients have five times the rate of dementia diagnosis within three years. Aerobic exercise may induce neuroprotective mechanisms that help to preserve, and even increase, brain volume and cognition. We seek to determine whether aerobic fitness training helps to protect brain volume and cognitive function after stroke compared to an active, non-aerobic control.

METHODS

In this Phase IIb, single blind, randomised controlled trial, 100 ischaemic stroke participants, recruited at two months post-stroke, will be randomly allocated to either the intervention (aerobic and strength exercise) or active control (stretching and balance training). Participants will attend one-hour, individualised exercise sessions, three days-per-week for eight weeks. Assessments at two months (baseline), four months (post-intervention), and one year (follow-up) post-stroke will measure brain volume, cognition, mood, cardiorespiratory fitness, physical activity, blood pressure and blood biomarkers.Study outcome: Our primary outcome measure is hippocampal volume at four months after stroke. We hypothesise that participants who undertake the prescribed intervention will have preserved hippocampal volume at four months compared to the control group. We also hypothesise that this group will have preserved total brain volume and cognition, better mood, fitness, and higher levels of physical activity, than those receiving stretching and balance training.

DISCUSSION

The promise of exercise training to prevent, or slow, the accelerated rates of brain atrophy and cognitive decline experienced by stroke survivors needs to be tested. Post Ischaemic Stroke Cardiovascular Exercise Study has the potential, if proven efficacious, to identify a new treatment that could be readily translated to the clinic.

Prediction of Maximal Oxygen Consumption from Rating of Perceived Exertion (RPE) using a Modified Total-body Recumbent Stepper

Exercise training is crucial to improve cardiovascular health and quality of life in people with spinal cord injuries (SCI). A key limitation is the lack of validated submaximal tests to evaluate and predict cardiovascular fitness in this population. The purpose of this study was to validate a submaximal test to predict maximal oxygen consumption for individuals with SCI. Ten able-bodied participants and two individuals with SCI completed a rating of perceived exertion (RPE)-based submaximal oxygen consumption test and a graded maximal oxygen consumption test on a NuStep T4 recumbent stepper. Prediction of VO2max from an RPE-based protocol is feasible and can produce reliable predicted VO2max values in the able bodied population. This study is a proof of concept to the implementation of a submaximal test protocol using a total body recumbent stepper to predict VO2max in able-bodied individuals. Additionally, this study shows evidence of feasibility of performing this test in SCI individuals.

A Bout of High Intensity Interval Training Lengthened Nerve Conduction Latency to the Non-exercised Affected Limb in Chronic Stroke

Objective: Evaluate intensity-dependent effects of a single bout of high intensity interval training (HIIT) compared to moderate intensity constant-load exercise (MICE) on corticospinal excitability (CSE) and effects on upper limb performance in chronic stroke.

Design: Randomized cross-over trial.

Setting: Research laboratory in a tertiary rehabilitation hospital.

Participants: Convenience sample of 12 chronic stroke survivors.

Outcome measures: Bilateral CSE measures of intracortical inhibition and facilitation, motor thresholds, and motor evoked potential (MEP) latency using transcranial magnetic stimulation. Upper limb functional measures of dexterity (Box and Blocks Test) and strength (pinch and grip strength).

Results: Twelve (10 males; 62.50 ± 9.0 years old) chronic stroke (26.70 ± 23.0 months) survivors with moderate level of residual impairment participated. MEP latency from the ipsilesional hemisphere was lengthened after HIIT (pre: 24.27 ± 1.8 ms, and post: 25.04 ± 1.8 ms, p = 0.01) but not MICE (pre: 25.49 ± 1.10 ms, and post: 25.28 ± 1.0 ms, p = 0.44). There were no significant changes in motor thresholds, intracortical inhibition or facilitation. Pinch strength of the affected hand decreased after MICE (pre: 8.96 ± 1.9 kg vs. post: 8.40 ± 2.0 kg, p = 0.02) but not after HIIT (pre: 8.83 ± 2.0 kg vs. post: 8.65 ± 2.2 kg, p = 0.29). Regardless of type of aerobic exercise, higher total energy expenditure was associated with greater increases in pinch strength in the affected hand after exercise (R² = 0.31, p = 0.04) and decreases in pinch strength of the less affected hand (R² = 0.26 p = 0.02).

Conclusion: A single bout of HIIT resulted in lengthened nerve conduction latency in the affected hand that was not engaged in the exercise. Longer latency could be related to the cross-over effects of fatiguing exercise or to reduced hand spasticity. Somewhat counterintuitively, pinch strength of the affected hand decreased after MICE but not HIIT. Regardless of the structure of exercise, higher energy expended was associated with pinch strength gains in the affected hand and strength losses in the less affected hand. Since aerobic exercise has acute effects on MEP latency and hand strength, it could be paired with upper limb training to potentiate beneficial effects.

Evaluation of supervised multimodal prehabilitation programme in cancer patients undergoing colorectal resection: a randomized control trial

BACKGROUND

Prehabilitation has been previously shown to be more effective in enhancing postoperative functional capacity than rehabilitation alone. The purpose of this study was to determine whether a weekly supervised exercise session could provide further benefit to our current prehabilition program, when comparing to standard post-surgical rehabilitation.

METHODS

A parallel-arm single-blind randomized control trial was conducted in patients scheduled for non-metastatic colorectal cancer resection. Patients were assigned to either a once weekly supervised prehabilitation (PREHAB+, n = 41) or standard rehabilitation (REHAB, n = 39) program. Both multimodal programs were home-based program and consisted of moderate intensity aerobic and resistance exercise, nutrition counseling with daily whey protein supplementation and anxiety-reduction strategies. Perioperative care was standardized for both groups as per enhanced recovery after surgery (ERAS^®) guidelines. Functional exercise capacity, as determined by the 6-minute walk test distance (6MWD), was the primary outcome. Exercise quantity, intensity and energy expenditure was determined by the CHAMPS questionnaire.

RESULTS

Both groups were comparable for baseline walking capacity (PREHAB+: 448 m [IQR 375-525] vs. REHAB: 461 m [419-556], p=.775) and included a similar proportion of patients who improved walking capacity (>20 m) during the preoperative period (PREHAB+: 54% vs. REHAB: 38%, p = .222). After surgery, changes in 6MWD were also similar in both groups. In PREHAB+, however, there was a significant association between physical activity energy expenditure and 6MWD (p < .01). Previously inactive patients were more likely to improve functional capacity due to PREHAB+ (OR 7.07 [95% CI 1.10-45.51]).

CONCLUSIONS

The addition of a weekly supervised exercise session to our current prehabilitation program did not further enhance postoperative walking capacity when compared to standard REHAB care. Sedentary patients, however, seemed more likely to benefit from PREHAB+. An association was found between energy spent in physical activity and 6MWD. This information is important to consider when designing cost-effective prehabilitation programs.

Optimizing a Treadmill Ramp Protocol to Evaluate Aerobic Capacity of Hemiparetic Poststroke Patients

Bernardes, WL, Montenegro, RA, Monteiro, WD, de Almeida Freire, R, Massaferri, R, and Farinatti, P. Optimizing a treadmill ramp protocol to evaluate aerobic capacity of hemiparetic poststroke patients. J Strength Cond Res 32(3): 876-884, 2018-A correct assessment of cardiopulmonary capacity is important for aerobic training within motor rehabilitation of poststroke hemiparetic patients (PSHPs). However, specific cardiopulmonary exercise testing (CPET) for these patients are scarce. We proposed adaptations in a protocol originally developed for PSHPs by Ovando et al. (CPET1). We hypothesized that our adapted protocol (CPET2) would improve the original test, by preventing early fatigue and increasing patients' peak performance. Eleven PSHPs (52 ± 14 years, 10 men) performed both protocols. CPET2 integrated changes in final speed (100-120% vs. 140% maximal speed in 10-m walking test), treadmill inclination (final inclination of 5 vs. 10%), and estimated test duration (10 vs. 8 minutes) to smooth the rate of workload increment of CPET1. Peak oxygen uptake (V[Combining Dot Above]O2peak) (20.3 ± 6.1 vs. 18.6 ± 5.0 ml·kg·min; p = 0.04), V[Combining Dot Above]O2 at gas exchange transition (V[Combining Dot Above]O2-GET) (11.5 ± 2.9 vs. 9.8 ± 2.0 ml·kg·min; p = 0.04), and time to exhaustion (10 ± 3 vs. 6 ± 2 minutes; p < 0.001) were higher in CPET2 than in CPET1. Slopes and intercepts of regressions describing relationships between V[Combining Dot Above]O2 vs. workload, heart rate vs. workload, and V[Combining Dot Above]O2 vs. heart rate were similar between CPETs. However, standard errors of estimates obtained for regressions between heart rate vs. workload (3.0 ± 1.3 vs. 3.8 ± 1.0 b·min; p = 0.004) and V[Combining Dot Above]O2 vs. heart rate (6.0 ± 2.1 vs. 4.8 ± 2.4 ml·kg·min; p = 0.05) were lower in CPET2 than in CPET1. In conclusion, the present adaptations in Ovando's CPET protocol increased exercise tolerance of PSHPs, eliciting higher V[Combining Dot Above]O2peak and V[Combining Dot Above]O2-GET, preventing earlier fatigue, and providing better physiological relationships along submaximal workloads.

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.

Intensifying Functional Task Practice to Meet Aerobic Training Guidelines in Stroke Survivors

Objective: To determine whether stroke survivors could maintain workloads during functional task practice that can reach moderate levels of cardiometabolic stress (i.e., ≥40% oxygen uptake reserve ([Formula: see text]O2R) for ≥20 min) without the use of ergometer-based exercise. Design: Cross-sectional study using convenience sampling. Setting: Research laboratory in a tertiary rehabilitation hospital. Participants: Chronic hemiparetic stroke survivors (>6-months) who could provide consent and walk with or without assistance. Intervention: A single bout of intermittent functional training (IFT). The IFT protocol lasted 30 min and involved performing impairment specific multi-joint task-oriented movements structured into circuits lasting ~3 min and allowing 30-45 s recovery between circuits. The aim was to achieve an average heart rate (HR) 30-50 beats above resting without using traditional ergometer-based aerobic exercise. Outcome measures: Attainment of indicators for moderate intensity aerobic exercise. Oxygen uptake ([Formula: see text]O2), carbon dioxide production ([Formula: see text]CO2), and HR were recorded throughout the 30 min IFT protocol. Values were reported as percentage of [Formula: see text]O2R, HR reserve (HRR) and HRR calculated from predicted maximum HR (HRRpred), which were determined from a prior maximal graded exercise test. Results: Ten (3-female) chronic (38 ± 33 months) stroke survivors (70% ischemic) with significant residual impairments (NIHSS: 3 ± 2) and a high prevalence of comorbid conditions (80% ≥ 1) participated. IFT significantly increased all measures of exercise intensity compared to resting levels: [Formula: see text]O2 (Δ 820 ± 290 ml min-1, p < 0.001), HR (Δ 42 ± 14 bpm, p < 0.001), and energy expenditure (EE; Δ 4.0 ± 1.4 kcal min-1, p < 0.001). Also, mean values for percentage of [Formula: see text]O2R (62 ± 19), HRR (55 ± 14), and HRRpred (52 ± 18) were significantly higher than the minimum threshold (40%) indicating achievement of moderate intensity aerobic exercise (p = 0.004, 0.016, and 0.043, respectively). Conclusion: Sufficient workloads to achieve moderate levels of cardiometabolic stress can be maintained in chronic stroke survivors using impairment-focused functional movements that are not dependent on ergometers or other specialized equipment.

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.

Dynamics of middle cerebral artery blood flow velocity during moderate-intensity exercise

The dynamic response to a stimulus such as exercise can reveal valuable insights into systems control in health and disease that are not evident from the steady-state perturbation. However, the dynamic response profile and kinetics of cerebrovascular function have not been determined to date. We tested the hypotheses that bilateral middle cerebral artery blood flow mean velocity (MCA_V) increases exponentially following the onset of moderate-intensity exercise in 10 healthy young subjects. The MCA_V response profiles were well fit to a delay (TD) + exponential (time constant, τ) model with substantial agreement for baseline [left (L): 69, right (R): 64 cm/s, coefficient of variation (CV) 11%], response amplitude (L: 16, R: 13 cm/s, CV 23%), TD (L: 54, R: 52 s, CV 9%), τ (L: 30, R: 30 s, CV 22%), and mean response time (MRT) (L: 83, R: 82 s, CV 8%) between left and right MCA_V as supported by the high correlations (e.g., MRT r = 0.82, P < 0.05) and low CVs. Test-retest reliability was high with CVs for the baseline, amplitude, and MRT of 3, 14, and 12%, respectively. These responses contrasted markedly with those of three healthy older subjects in whom the MCA_V baseline and exercise response amplitude were far lower and the kinetics slowed. A single older stroke patient showed baseline ipsilateral MCA_V that was lower still and devoid of any exercise response whatsoever. We conclude that kinetics analysis of MCA_V during exercise has significant potential to unveil novel aspects of cerebrovascular function in health and disease.NEW & NOTEWORTHY Resolution of the dynamic stimulus-response profile provides a greater understanding of the underlying the physiological control processes than steady-state measurements alone. We report a novel method of measuring cerebrovascular blood velocity (MCAv) kinetics under ecologically valid conditions from rest to moderate-intensity exercise. This technique reveals that brain blood flow increases exponentially following the onset of exercise with 1) a strong bilateral coherence in young healthy individuals, and 2) a potential for unique age- and disease-specific profiles.

Recumbent Stepper Submaximal Test response is reliable in adults with and without stroke

PURPOSE

The purpose of the present study was to determine the reliability of the exercise response (predicted peak VO2) using the total body recumbent stepper (TBRS) submaximal exercise test in: 1) healthy adults 20-70 years of age and 2) adults participating in inpatient stroke rehabilitation. We hypothesized that the predicted peak VO2 (Visit 1) would have an excellent relationship (r > 0.80) to predicted peak VO2 (Visit 2). We also wanted to test whether the exercise response at Visit 1 and Visit 2 would be significantly different.

METHODS

Healthy adults were recruited from the Kansas City metro area. Stroke participants were recruited during their inpatient rehabilitation stay. Eligible participants completed 2 TBRS submaximal exercise tests between 24 hours and 5 days at similar times of day.

RESULTS

A total of 70 participants completed the study. Healthy adults (n = 50) were 36 M, 38.1 ± 10.1 years and stroke participants (n = 20) were 15 M, 62.5 ± 11.8 years of age. The exercise response was reliable for healthy adults (r = 0.980, p<0.01) and stroke participants (r = 0.987, p<0.01) between Visit 1 and Visit 2. Repeated Measures ANOVA showed a significant difference in predicted values between the two visits for healthy adults (47.2 ± 8.4 vs 47.7 ± 8.5 mL∙kg-1∙min-1; p = 0.04) but not for stroke participants (25.0 ± 9.9 vs 25.3 ± 11.4 mL∙kg-1∙min-1; p = 0.65).

CONCLUSION

These results suggest that the exercise response is reliable using the TBRS submaximal exercise test in this cohort of healthy adults and stroke participants.

Comparison of the effects on dynamic balance and aerobic capacity between objective and subjective methods of high-intensity robot-assisted gait training in chronic stroke patients: a randomized controlled trial

BACKGROUND

Robot-assisted gait training (RAGT) is effective for improving dynamic balance and aerobic capacity, but previous RAGT method does not set suitable training intensity. Recently, high-intensity treadmill gait training at 70% of heart rate reserve (HRR) was used for improving aerobic capacity and dynamic balance.

PURPOSE

This study was designed to compare the effectiveness between objective and subjective methods of high-intensity RAGT for improving dynamic balance and aerobic capacity in chronic stroke.

METHODS

Subjects were randomly allocated into experimental (n = 17) and control (n = 17) groups. The experimental group underwent high-intensity RAGT at 70% of HRR, whereas the control group underwent high-intensity RAGT at an RPE of 15. Both groups received their assigned training for 30 min per session, 3 days per week for 6 weeks. All subjects also received an additional 30 min of conventional physical therapy. Before and after each of the 18 sessions, the dynamic balance and aerobic capacity of all subjects were evaluated by a blinded examiner.

RESULTS

After training, Berg Balance Scale (BBS) and Timed Up and Go Test scores, VO₂max, and VO₂max/kg were significantly increased in both groups (p < 0.05). These variables in experimental group were significantly greater than control group. However, the BBS score was not significantly different between both groups. All subjects completed high-intensity RAGT. No adverse effect of training was observed in both groups.

CONCLUSION

High-intensity RAGT at 70% of HRR significantly improved dynamic balance and aerobic capacity more than RAGT at RPE of 15. These results suggest that high-intensity RAGT at 70% of HRR is safe and effective for improving dynamic balance and aerobic capacity in chronic stroke.

Activity for Diabetic Polyneuropathy (ADAPT): Study Design and Protocol for a 2-Site Randomized Controlled Trial

BACKGROUND

Half of all patients with diabetes develop diabetic peripheral neuropathy (DPN), a complication leading to reduced mobility and quality of life. Although there are no proven pharmacologic approaches to reduce DPN risk or slow its progression, evidence suggests that physical activity may improve symptoms and enhance peripheral nerve regeneration.

OBJECTIVE

The aim of the study will be to determine the impact of an intense lifestyle intervention on neuropathy progression and quality of life in individuals with DPN.

DESIGN

The study will be a randomized controlled trial.

SETTING

The study will be conducted at 2 academic medical centers.

PARTICIPANTS

The participants will be 140 individuals with type 2 diabetes and mild to moderate DPN.

INTERVENTION

The intervention group will receive 18 months of supervised exercise training, actigraphy-based counseling to reduce sedentary behavior, and individualized dietary counseling. Control group participants will receive diet and activity counseling at baseline and at 9 months.

MEASUREMENTS

The primary outcomes are neuropathy progression as measured by intraepidermal nerve fiber density in a distal thigh skin biopsy and the Norfolk Quality of Life-Diabetic Neuropathy score. Secondary outcomes include pain, gait, balance, and mobility measures.

LIMITATIONS

Due to the combined intervention approach, this protocol will not be able to determine which intervention components influence outcomes. There also may be difficulty with participant attrition during the 18-month study intervention.

CONCLUSIONS

The Activity for Diabetic Polyneuropathy (ADAPT) protocol resulted from a collaboration between physical therapists and neurologist researchers that includes as primary outcomes both a quality-of-life measure (NQOL-DN) and a physiologic biomarker (IENFD). It has the potential to demonstrate that an intensive lifestyle intervention may be a sustainable, clinically effective approach for people with DPN that improves patient outcomes and can have an immediate impact on patient care and future clinical trials.

Decreased tidal volume may limit cardiopulmonary performance during exercise in subacute stroke

PURPOSE

The aim of this retrospective study was to determine whether pulmonary function was reduced at submaximal and peak exercise in subacute stroke (SG) when compared with sedentary adults (CON).

METHODS

Ten individuals with subacute stroke and 10 sedentary, age- and gender-matched adults performed cardiopulmonary exercise testing (CPET), using a recumbent stepper. We used independent t tests to determine between-group differences at peak effort. We used repeated-measures analysis of variance with Test Minute (minutes 1-6) as the within-subject factor and Group (SG, CON) as the between-subject factor to assess cardiopulmonary submaximal performance.

RESULTS

The SG had significantly lower values (P < .05) for oxygen uptake, minute ventilation ((Equation is included in full-text article.)E), and tidal volume (VT) than CON at peak effort of the CPET. During CPET submaximal effort, we report a significant main effect for Test Minute and Group for VT and respiratory rate but no main effect of Group for (Equation is included in full-text article.)E. To maintain adequate (Equation is included in full-text article.)E during submaximal effort and decreased VT, higher respiratory rate was observed.

CONCLUSIONS

These results suggest that diminished VT in subacute stroke patients may limit performance during submaximal and peak effort of CPET. Rehabilitation professionals should consider methods for improving pulmonary function during stroke rehabilitation.

Efficacy of Feedback-Controlled Robotics-Assisted Treadmill Exercise to Improve Cardiovascular Fitness Early After Stroke: A Randomized Controlled Pilot Trial

BACKGROUND AND PURPOSE

Cardiovascular fitness is greatly reduced after stroke. Although individuals with mild to moderate impairments benefit from conventional cardiovascular exercise interventions, there is a lack of effective approaches for persons with severely impaired physical function. This randomized controlled pilot trial investigated efficacy and feasibility of feedback-controlled robotics-assisted treadmill exercise (FC-RATE) for cardiovascular rehabilitation in persons with severe impairments early after stroke.

METHODS

Twenty individuals (age 61 ± 11 years; 52 ± 31 days poststroke) with severe motor limitations (Functional Ambulation Classification 0-2) were recruited for FC-RATE or conventional robotics-assisted treadmill exercise (RATE) (4 weeks, 3 × 30-minute sessions/wk). Outcome measures focused on peak cardiopulmonary performance parameters, training intensity, and feasibility, with examiners blinded to allocation.

RESULTS

All 14 allocated participants (70% of recruited) completed the intervention (7/group, withdrawals unrelated to intervention), without serious adverse events occurring. Cardiovascular fitness increased significantly in both groups, with peak oxygen uptake increasing from 14.6 to 17.7 mL · kg · min (+17.8%) after 4 weeks (45.8%-55.7% of predicted maximal aerobic capacity; time effect P = 0.01; no group-time interaction). Training intensity (% heart rate reserve) was significantly higher for FC-RATE (40% ± 3%) than for conventional RATE (14% ± 2%) (P = 0.001).

DISCUSSION AND CONCLUSIONS

Substantive overall increases in the main cardiopulmonary performance parameters were observed, but there were no significant between-group differences when comparing FC-RATE and conventional RATE. Feedback-controlled robotics-assisted treadmill exercise significantly increased exercise intensity, but recommended intensity levels for cardiovascular training were not consistently achieved. Future research should focus on appropriate algorithms within advanced robotic systems to promote optimal cardiovascular stress.Video abstract available for more insights from the authors (Supplemental Digital Content 1, http://links.lww.com/JNPT/A107).

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.

Effects of aerobic exercise training on fitness and walking-related outcomes in ambulatory individuals with chronic incomplete spinal cord injury

Study Design

Single group, pretest-posttest study.

Objectives

To determine the effects of a non-task-specific, voluntary, progressive aerobic exercise training (AET) intervention on fitness and walking-related outcomes in ambulatory adults with chronic motor-incomplete SCI.

Setting

Rehabilitation research center.

Methods

Ten ambulatory individuals (50% female; 57.94 ± 9.33 years old; 11.11 ± 9.66 years post injury) completed voluntary, progressive moderate-to-vigorous intensity AET on a recumbent stepper three days per week for six weeks. The primary outcome measures were aerobic capacity (VO_2peak) and self-selected overground walking speed (OGWS). Secondary outcome measures included: walking economy, six-minute walk test (6MWT), daily step counts, Walking Index for Spinal Cord Injury (WISCI-II), Dynamic Gait Index (DGI), and Berg Balance Scale (BBS).

Results

Nine participants completed all testing and training. Significant improvements in aerobic capacity (P=0.011), OGWS (P=0.023), the percentage of VO_2peak utilized while walking at self-selected speed (P=0.03), and daily step counts (P=0.025) resulted following training.

Conclusions

The results indicate that total-body, voluntary, progressive AET is safe, feasible, and effective for improving aerobic capacity, walking speed, and select walking-related outcomes in an exclusively ambulatory SCI sample. This study suggests the potential for non-task-specific aerobic exercise to improve walking following incomplete SCI and builds a foundation for further investigation aimed at the development of exercise based rehabilitation strategies to target functionally limiting impairments in ambulatory individuals with chronic SCI.

Does aerobic exercise and the FITT principle fit into stroke recovery?

Sedentary lifestyle after stroke is common which results in poor cardiovascular health. Aerobic exercise has the potential to reduce cardiovascular risk factors and improve functional capacity and quality of life in people after stroke. However, aerobic exercise is a therapeutic intervention that is underutilized by healthcare professionals after stroke. The purpose of this review paper is to provide information on exercise prescription using the FITT principle (frequency, intensity, time, type) for people after stroke and to guide healthcare professionals to incorporate aerobic exercise into the plan of care. This article discusses the current literature outlining the evidence base for incorporating aerobic exercise into stroke rehabilitation. Recently, high-intensity interval training has been used with people following stroke. Information is provided regarding the early but promising results for reaching higher target heart rates.

Pilot Study of Exercise Therapy on Painful Diabetic Peripheral Neuropathy

OBJECTIVE

Painful diabetic peripheral neuropathy (DPN) is a common complication of diabetes. While the beneficial effect of exercise on diabetes is well established, its effect specifically on painful DPN has not been thoroughly explored. The objective of this pilot study was to examine the effect of aerobic exercise on pain in people with DPN.

METHODS

Fourteen sedentary individuals (mean age 57 ± 5.11 years) with painful DPN were enrolled in a 16-week, supervised aerobic exercise program. The Brief Pain Inventory-Diabetic Peripheral Neuropathy was used to assess pain intensity (worst, least, average, now) and pain interference with daily life (activity, mood, walk, normal work, relationship, sleep, enjoyment of life) pre intervention and postintervention. Body mass index (BMI), maximum oxygen uptake (VO2max ), hemoglobin A1c (HbA1c), and blood pressure were also measured preintervention and postintervention as secondary outcomes of interest.

RESULTS

Significant reductions in pain interference were observed with walking (4.93 ± 3.03 pre to 3.29 ± 2.89 post, P = 0.016), normal work (5.39 ± 3.32 pre to 3.79 ± 3.04 post, P = 0.032), relationship with others (3.96 ± 3.53 pre to 1.29 ± 1.27 post, P = 0.006), sleep (5.11 ± 3.04 pre to 3.5 ± 3.03 post, P = 0.02), and the overall pain interference (4.65 ± 2.70 pre to 2.97 ± 2.22 post, P = 0.013) following the intervention; however, there was no change in pain intensity. VO2max increased significantly postintervention (16.02 ± 3.84 ml/kg/min pre to 17.18 ± 4.19 ml/kg/min, P = 0.028), while BMI, HbA1c, and blood pressure remained unchanged.

CONCLUSION

These preliminary results suggest that perceived pain interference may be reduced following an aerobic exercise intervention among people with painful DPN, without a change in pain intensity. Further validation by a RCT is needed.

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.