Reliability and Validity of the 6-Minute Step Test for Clinical Assessment of Cardiorespiratory Fitness in People at Risk of Cardiovascular Disease.

Giacomantonio, N, Morrison, P, Rasmussen, R, and MacKay-Lyons, MJ. Reliability and validity of the 6-minute step test for clinical assessment of cardiorespiratory fitness in people at risk of cardiovascular disease. J Strength Cond Res 34(5): 1376-1382, 2020-The purpose of this study was to determine the test-retest reliability and validity of the 6-minute step test (6MST) as a potential assessment of cardiorespiratory fitness (CRF) of people at risk of cardiovascular disease (CVD). A prospective, cross-sectional, correlational study design was used. A single cohort of 30 adults with 2 or more risk factors for CVD was recruited. Exercise tests were scheduled on 2 days, separated by 1 week. Validity was determined by comparing 6MST results with those obtained in a symptom-limited treadmill test and the 6-minute walk test (6MWT). Main outcome variables were peak heart rate (HRpeak) and peak oxygen consumption (V[Combining Dot Above]O2peak) measured during the 6MST, treadmill test, and 6MWT. Test-retest reliability of HRpeak and V[Combining Dot Above]O2peak during the 6MST was very strong (intraclass correlation coefficient [ICC], 0.92; 95% confidence interval [CI], 0.83-0.97 and ICC, 0.93; 95% CI, 0.84-0.97, respectively). Correlations were also very strong between 6MST and treadmill test HRpeak (r = 0.81) and between 6MST and treadmill test V[Combining Dot Above]O2peak (r = 0.88). Correlations were moderate between 6MST HRpeak and 6MWT steady-state HR (r = 0.57) and strong between 6MST V[Combining Dot Above]O2peak and 6MWT steady-state V[Combining Dot Above]O2 (r = 0.70). The 6MST seems to be a reliable, valid option for assessing CRF of people at risk of CVD in a broad range of clinical settings. Providing practical, accessible tests will help facilitate the goal of establishing CRF as a clinical vital sign. The next step in the development of the 6MST should be to identify the most appropriate 6MST predictor variables to estimate V[Combining Dot Above]O2max.

A randomized trial of two home-based exercise programmes to improve functional walking post-stroke.

OBJECTIVE: To estimate the relative effectiveness in improving walking ability and other mobility and health outcomes post-stroke of two home-based exercise programmes - stationary cycling and an exercise and walking programme. DESIGN: An observer-blinded, randomized, pragmatic, trial with repeated measures. SETTING: Hospital centers in two Canadian cities. SUBJECTS: People within 12 months of acute stroke who were able to walk >10 meters independently and healthy enough to engage in exercise. INTERVENTIONS: Two dose-equivalent interventions, one involving stationary cycling and the other disability-targeted interventions were tested. Both protocols required daily moderate intensity exercise at home building up to 30 minutes per day. One group exercised on a stationary bicycle, the second group carried out mobility exercises and brisk walking. MAIN MEASURES: The primary outcome was walking capacity as measured by the six-minute walk test (6MWT). Secondary outcomes were physical function, role participation, health-related quality of life exercise adherence, and adverse events. RESULTS: The study failed to meet recruitment targets: 87 participants (cycle group, n = 43; exercise group, n = 44) participated. No significant effects of group or time were revealed for the 6MWT, which was approximately 320 m at randomization. A significant effect for role participation was found in favor of the exercise group (global odds ratio (OR) for cycling vs. exercise was 0.51; 95% confidence interval (CI), 0.27-0.95). Change in the 6MWT between highest and lowest adherence categories was statistically significant (p = 0.022). CONCLUSIONS: Both programmes were equally effective in maintaining walking capacity after discharge from stroke rehabilitation; or were equally ineffective in improving walking capacity. Clinical Trials Gov number: NCT00786045.

Reduced cardiorespiratory fitness after stroke: biological consequences and exercise-induced adaptations.

Evidence from several studies consistently shows decline in cardiorespiratory (CR) fitness and physical function after disabling stroke. The broader implications of such a decline to general health may be partially understood through negative poststroke physiologic adaptations such as unilateral muscle fiber type shifts, impaired hemodynamic function, and decrements in systemic metabolic status. These physiologic changes also interrelate with reductions in activities of daily living (ADLs), community ambulation, and exercise tolerance, causing a perpetual cycle of worsening disability and deteriorating health. Fortunately, initial evidence suggests that stroke participants retain the capacity to adapt physiologically to an exercise training stimulus. However, despite this evidence, exercise as a therapeutic intervention continues to be clinically underutilized in the general stroke population. Far more research is needed to fully comprehend the consequences of and remedies for CR fitness impairments after stroke. The purpose of this brief review is to describe some of what is currently known about the physiological consequences of CR fitness decline after stroke. Additionally, there is an overview of the evidence supporting exercise interventions for improving CR fitness, and associated aspects of general health in this population.

Ethics of involving children in health-related research: applying a decision-making framework to a clinical trial.

PURPOSE: This paper explores ethical issues related to the involvement of children in health-related research through the application of a conceptual model (the Miller and Kenny framework) to a current clinical trial on casting protocols for equinus gait of children with cerebral palsy (CP). SUMMARY OF KEY POINTS: The direct involvement of children in health-related research is important for maintaining and improving standards of paediatric clinical care. Ethical considerations around investigations involving this highly vulnerable population are complex, however, requiring the involvement of many levels of decision makers-government, research ethics boards (REBs), health care providers, parents, and children. The Miller and Kenny framework is useful in distinguishing these levels and heightening awareness of the complexities of the issues around engaging children in research. Considerations include the role of parents/caregivers in decision making, individual assessment of the child's decisional capacities, close attention to the child's context and life experience, provision of developmentally appropriate information about the research study, and careful assessment of dissent prior to withdrawing the child from the study. RECOMMENDATIONS: Physical therapists involved in paediatric clinical practice and/or research must be knowledgeable about ethical principles, policies, and REB requirements. The Miller and Kenny framework is a helpful guide to clarify decision-making roles around children's participation in research.

Metabolic syndrome and its components in individuals undergoing rehabilitation after stroke.

BACKGROUND AND PURPOSE: : Individuals participating in stroke rehabilitation are in jeopardy of future vascular events, including a second stroke. Nevertheless, vascular risk assessment is often overlooked in this population. Metabolic syndrome (MetS) may be a useful construct for risk assessment because of its predictive ability in distinguishing patients who are at high risk of future morbidity. This study documented the prevalence of MetS and its components in stroke rehabilitation patients. In addition, clinical characteristics of subgroups with and without MetS were compared. METHODS: : Health records of 200 adult patients who had participated in inpatient stroke rehabilitation were reviewed. The prevalence and extent of clustering of the five components of MetS-obesity, hypertension, hypertriglyceridemia, low high-density lipoprotein cholesterol, and insulin resistance-were examined. RESULTS: : Of the total sample, 61% had MetS and 97% had at least one MetS component, with hypertension and low high-density lipoprotein cholesterol being the most prevalent. The number of comorbidities, number of prescription drugs, and history of coronary heart disease were positively related to the presence of MetS. The components were predicted by a single underlying factor, providing support for the validity of using the MetS construct to assess vascular risk in this population. DISCUSSION AND CONCLUSIONS: : Awareness of the high prevalence of MetS in individuals undergoing stroke rehabilitation should motivate physical therapists and other rehabilitation clinicians to intervene to prevent the recurrence of vascular events. Early screening for this high-risk condition and implementation of targeted interventions to reduce future vascular morbidity should become priorities in stroke rehabilitation.

Assessment protocol for serial casting after botulinum toxin a injections to treat equinus gait.

PURPOSE: The purpose of this study was to investigate feasibility of an assessment protocol for a trial of post-Botox casting to treat equinus gait in cerebral palsy. METHODS: Ten children (ages, 26-75 months) were recruited. Nine were assessed 1 week before botulinum toxin-A injections and reassessed 1 week after removal of the final cast. The assessment protocol included Modified Ashworth Scale (MAS), Modified Tardieu Scale (MTS), Gross Motor Function Measure-66 (GMFM-66), Pediatric Evaluation of Disability Inventory (PEDI), and GAITRite. Feasibility was based on acceptability of the protocol, inter-rater reliability, and responsiveness of outcome measures. RESULTS: The assessment protocol was acceptable and practical. Inter-rater reliability for MAS, MTS, and GMFM ranged from moderate to excellent. Improvements were found in MTS and MAS scores for dorsiflexion and hamstring (p < 0.01), GMFM-66 (p = 0.01), and Pediatric Evaluation of Disability Inventory mobility (p = 0.01), self-care (p = 0.01), and social function (p = 0.00). GAITRite revealed reductions in speed (p = 0.00) and cadence (p = 0.01). CONCLUSIONS: Feasibility was confirmed. Recommendations include raising minimum age and delaying gait analysis.

Exercise capacity and cardiovascular adaptations to aerobic training early after stroke.

Clinicians are becoming increasingly interested in the use of aerobic training to enhance functional outcomes after stroke. Several studies have demonstrated the effectiveness of training among individuals in the chronic poststroke period. However, there is limited information on the response to training in earlier stages of recovery. The purpose of this article is to review what is known regarding the capacity of people early after stroke (<4 months) to respond to the physiological demands of exercise (exercise capacity) as well as their ability to make long-term cardiovascular adaptations to aerobic exercise. There is evidence that exercise capacity, as measured by peak oxygen consumption on maximal exercise tests, is reduced in this population. There is also evidence, albeit limited, that exercise trainability soon after stroke can be both feasible and safe, if appropriate screening and monitoring are used. Moreover, there are early indications that activity-level functions such as walking speed, mobility, and balance may be enhanced through such programs. Further research is necessary to elucidate the most appropriate timing and design of fitness programs for people early after stroke.

Longitudinal changes in exercise capacity after stroke.

OBJECTIVE: To determine if stroke patients without specific aerobic training experience a change in the first 6 months after stroke. DESIGN: Descriptive, longitudinal study with repeated measures of exercise capacity at 1, 2, 3, and 6 months after stroke. SETTING: Exercise testing laboratory in a tertiary care hospital. PARTICIPANTS: Consecutive sample of 25 patients (mean age +/- standard deviation, 64.1+/-13.6 y) 1 month after first ischemic stroke. INTERVENTIONS: Not applicable. Main Outcome Measures Peak oxygen consumption (Vo(2)peak) was measured by open-circuit spirometry during maximal effort treadmill walking with 15% body-weight support. RESULTS: Mean Vo(2)peak increased from 14.8+/-5.3 mL x kg(-1). min(-1) at 1 month to 17.3+/-7.0 mL x kg(-1).min(-1) at 6 months after stroke (P=.003) or from 61.7%+/-16% to 71.3%+/-23% of age- and sex-related normative values for sedentary healthy adults (P=.008). CONCLUSIONS: Despite improvements in Vo(2)peak and other indices of cardiovascular training between 1 and 6 months poststroke, substantial limitations in exercise capacity persisted. Further study is needed to determine the extent to which these limitations can be modified through aerobic conditioning.

Exercise capacity early after stroke.

OBJECTIVE: To evaluate exercise capacity of patients with a poststroke interval of less than 1 month. DESIGN: Prospective, cohort, observational study. SETTING: Exercise testing laboratory in a tertiary care hospital. PARTICIPANTS: Twenty-nine patients (mean age +/- standard deviation, 64.9+/-13.5 y) with a poststroke interval of 26.0+/-8.8 days. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Peak exercise capacity (VO(2)peak) was measured by open-circuit spirometry during maximal effort treadmill walking with 15% body-weight support. RESULTS: Mean VO(2)peak was 14.4+/-5.1 mL. kg(-1). min(-1) or 60%+/-16% of age- and sex-related normative values for sedentary healthy adults. CONCLUSIONS: Exercise capacity approximately 1 month after stroke was compromised. Further research is needed to elucidate the physiologic basis of this low capacity.

Cardiovascular stress during a contemporary stroke rehabilitation program: is the intensity adequate to induce a training effect?

OBJECTIVES: To investigate the level of cardiovascular stress of physical therapy (PT) and occupational therapy (OT) sessions of a contemporary stroke rehabilitation program and to identify therapeutic activities that elicit heart rate responses adequate to induce a training effect. DESIGN: A descriptive, longitudinal study with heart rate and activity monitoring of PT and OT sessions at biweekly intervals, 2 to 14 weeks poststroke. SETTING: An acute inpatient stroke unit and inpatient and outpatient stroke rehabilitation units. PARTICIPANTS: A consecutive sample of 20 patients with ischemic stroke who participated in inpatient and outpatient stroke rehabilitation. INTERVENTION: Observation of routine PT and OT sessions for patients poststroke without influencing the extent and content of the sessions. MAIN OUTCOME MEASURE: Time per session in which heart rate was within the calculated target heart rate zone. RESULTS: Time per PT session spent in target heart rate zone was low (2.8+/-0.9 min), and per OT session was negligible (0.7+/-0.2 min) over the course of rehabilitation. CONCLUSIONS: The PT and OT sessions between 2 and 14 weeks poststroke did not elicit adequate cardiovascular stress to induce a training effect.