Cardiovascular deconditioning is common after stroke, with negative implications for recovery,1,2 participation in normal daily activities,1,3 and risk for cardiac events4,5 and recurrent stroke.6,7 To address poststroke deconditioning, the American Heart Association (AHA) recommends that aerobic exercise (AEX) should be a fundamental component of stroke rehabilitation.8 The recommended intensity of AEX is 40% to 70% of oxygen uptake (
O2) or heart rate (HR) reserve, 55% to 80% of HR max, or 11 to 14 on the 6 to 20 scale for rating of perceived exertion.8 The recommended duration and frequency of AEX are 20 to 60 minutes, 3 to 5 days per week and the recommended mode is treadmill walking, whenever feasible.8 With 3 to 6 months of such AEX, persons with stroke have achieved significant improvements in aerobic capacity,9–12 gait endurance,9,12 self-reported general mobility,9 cardiovascular risk factors,10,13 blood flow (peripheral14 and cerebral15), brain activation12 and cognition.16 Aerobic exercise has also been associated with significant improvements in lower extremity power17 and spasticity17 after stroke.
While AEX is not risk-free, the benefits are considered to outweigh the potential risks for the majority of people, including those who have had a stroke.8 However, 20% to 40% of persons poststroke have been found to have signs of silent myocardial ischemia during exercise and hypertension is a common comorbidity in this population.5,8 Therefore, it is recommended that exercise stress testing with electrocardiographic (ECG) and blood pressure (BP) monitoring should be part of a baseline preexercise medical evaluation whenever possible.8 When ECG stress testing is not feasible, continuous ECG monitoring during AEX or lower-intensity AEX has been suggested as alternative options.8
Although these recommendations have been in place since 2004,18 small observational studies19–21 and a recent survey of Canadian physical therapists (PTs)22 indicate that adherence may be challenging in clinical stroke rehabilitation practice. However, no previous studies have evaluated poststroke AEX prescription among PTs in the US health care system. Therefore, the purpose of this study was to assess AEX prescription for individuals poststroke by US PTs currently involved in clinical stroke rehabilitation, including AEX utilization, barriers to AEX prescription, dosing parameters, and safety considerations.
A cross-sectional Web-based survey study was conducted. This study was approved by the University of Cincinnati institutional review board. The survey instrument was developed using expert review and a PT focus group, including PTs from a variety of practice settings. E-mail address listings were obtained from state PT licensing boards in states where such listings were publicly available at no cost. This included Florida, New Jersey, Ohio, Texas, and Wyoming. Survey invitations were then sent to all licensed PTs with e-mail addresses on file in these states. Survey response analysis included all licensees with valid e-mail addresses and all respondents. Eligibility criteria for the remaining analyses were as follows: (1) currently involved in direct clinical patient care; (2) evaluated or treated at least 1 patient for stroke rehabilitation within the past 3 months; and (3) primary practice setting of acute care, home health, inpatient rehabilitation, extended care (skilled nursing or assisted living facility), or outpatient rehabilitation (not school, academic/research, or “other”).
A draft survey instrument was developed by adapting a previous questionnaire used to assess AEX prescription in neurological rehabilitation among Canadian PTs.22 The draft instrument was reviewed by the study team and an additional expert in poststroke AEX (Ada Tang, PT, PhD). After revisions, a clinical PT focus group was conducted to pilot test the survey and to provide additional feedback to further refine the instrument. The focus group included 6 PTs currently practicing in a variety of settings, including acute care, inpatient rehabilitation, extended care, home health, and outpatient rehabilitation. All focus group participants had been in practice for at least 1 year and provided written informed consent prior to participation. Participants were asked to provide feedback on all aspects of the survey, including the invitation to participate, overall organization, wording, redundant questions, important missing content and length.
The final survey instrument contained 30 closed-ended questions with either a list of response choices (categorical variables) or a field for numerical data entry (continuous variables; see Appendix, Supplemental Digital Content 2, for complete survey instrument, http://links.lww.com/JNPT/A168). There were 8 questions regarding respondent characteristics, 10 regarding AEX utilization and barriers, 5 regarding dosing parameters, and 7 regarding safety considerations. The survey was adaptive based on the responses to filtering questions. For example, the survey asked questions about AEX prescription for individuals with stroke only if the respondent indicated that they had evaluated or treated at least 1 patient for stroke rehabilitation within the past 3 months. The survey was written at a Flesch-Kincaid grade level23 of 11.1 and took approximately 15 to 20 minutes to complete.
Survey deployment and data management were performed through the REDCap Web-based system.24 After pilot testing of the survey deployment system by the study team, e-mail invitations to complete the survey were sent to nonduplicate, valid e-mail addresses of actively licensed PTs on file with the state licensing boards of Florida, New Jersey, Ohio, Texas, and Wyoming. The invitation explained the purpose of the survey, stated that individual responses would be confidential, provided the primary author's contact information, and contained a link to additional information about the study, including voluntary consent statements (see Appendix, Supplemental Digital Content 3, for example, e-mail invitation, http://links.lww.com/JNPT/A169). Each invitation contained a unique link to the survey to allow response tracking and prevent respondents from completing the survey multiple times. Several tactics were used as an attempt to increase the response rate22,25: (1) e-mail invitations were scheduled to deploy before 9 AM; (2) the invitation informed participants that they would be able to see some of the preliminary results after survey completion; (3) a page counter made participants aware of their progress in completing the survey; (4) respondents could save the survey and return to it later; (5) up to 2 follow-up e-mails were sent to nonrespondents in 2- to 3-week intervals; and 6) the survey was available for 3 months for each potential respondent and was open from July 31 to November 12, 2014.
For categorical variables, percentages were calculated by dividing the frequency of a particular response by the total number of responses for that item. Continuous variables were described by mean (standard deviation) when normally distributed and median (interquartile range) when nonnormally distributed (ie, significant Kolmogorov-Smirnov test).
To assess for nonresponse bias, the number of years licensed was calculated from state board data and compared between respondents and nonrespondents using the nonparametric Wilcoxon rank-sum test. If a significant difference in years licensed was found between respondents and nonrespondents, we planned to do a sensitivity analysis to assess the potential extent of nonresponse bias. This analysis would compare the AEX utilization responses between the underrepresented subgroup and the full sample used for analysis. The magnitude of the differences between the subgroup and the full sample would be used to estimate the amount of nonresponse bias.
To determine whether to report results separately for different practice settings, we tested for statistical differences in responses between respondents with different primary practice settings. This analysis was performed for each question. Chi-square tests were used for categorical variables and Kruskal-Wallis tests were used for continuous variables, because they were not normally distributed. When significant (P < 0.05) differences between practice settings were found for an item, pairwise comparisons were obtained using Bonferroni adjustment for multiple comparisons. The Benjamini-Hochberg procedure26 was additionally used to control the false discovery rate for multiple response variables. Practice settings that were not significantly different from each other were pooled together when reporting descriptive statistics.
A total of 32 544 survey invitations were sent to valid e-mail addresses and 1212 surveys were submitted (3.7% overall response rate). The individual state response rate varied from 3.3% to 7.5% (Table 1). Respondents had been licensed significantly longer than nonrespondents in all states except Wyoming. For the overall group of respondents, therapists with 0 to 10 years of state licensure were somewhat underrepresented and therapists with 20+ years of state licensure were somewhat overrepresented. However, the 1212 respondents were generally similar to American Physical Therapy Association members and the US PT workforce in that they were approximately 70% female, most commonly had doctoral physical therapy degrees, had been practicing for approximately 18 years on average, largely did not have specialty certification, were most commonly employed in outpatient clinics, and were primarily engaged in the musculoskeletal practice pattern (Table 2).
A total of 568 respondents indicated that they were currently involved in clinical practice (in a setting other than school, academic/research, or “other”) and had evaluated or treated at least 1 patient for stroke rehabilitation within the past 3 months. This subset of respondents was used for the remaining analyses. Within this subset, 76.9% (437/568) completed the last page of the survey, 63.2% (359/568) completed all questions presented (but were not necessarily presented every question based on responses to filtering questions), and 55.3% (314/568) completed all questions of interest for the analyses (Figure 1).
AEX Utilization and Barriers
Most respondents (87.8% [423/482]) agreed or strongly agreed that AEX should be incorporated into treatment programs of individuals with stroke, but fewer (72.1% [346/480]) reported that they were able to prescribe AEX for every individual with stroke for whom it was indicated (Table 3). These results did not significantly differ between practice settings. Reported AEX prescription rates were also similar between practice settings, except that acute care was significantly different from other practice settings. Therefore, the descriptive statistics for these questions are provided separately for acute care, as described in the “Methods” section. Aerobic exercise was prescribed for at least some individuals with stroke by 66.7% (54/81) of acute care therapists and 93.1% (375/403) of therapists in other settings. Aerobic exercise was prescribed for the majority of individuals with stroke by 24.7% (20/81) of acute care therapists and 61.3% (247/403) of therapists in other settings. Most respondents across all practice settings (83.8% [402/480]) perceived at least 1 barrier to routine AEX prescription for individuals with stroke. In the sensitivity analysis comparing the underrepresented subset of respondents with 0 to 10 years of state licensure to the full sample of respondents, the aforementioned results varied by less than 6% across all questions.
Among acute care PTs (n = 81), the most common perceived patient-related barriers to AEX prescription poststroke were limited ability to exercise at a training level (71.6%), balance impairments (69.1%), and cognitive/perceptual impairments (67.9%) (Figure 2). In this same subgroup, the most common perceived institutional barriers were short length of stay (79.0%), lack of exercise equipment (51.9%), and lack of time (45.7%).
Among nonacute care PTs (n = 399), the most common perceived patient-related barriers were limited ability to exercise at a training level (52.4%-82.4%, depending on practice setting), cognitive/perceptual impairments (44.8%-82.4%, depending on practice setting), and limited motivation (37.0%-56.9%, depending on practice setting). In this same subgroup, the most common perceived institutional barriers differed between practice settings (Figure 2).
A slight majority of acute care PTs (59.5% [47/79]) and a lower proportion of nonacute care PTs (32.3% [129/399]) reported that exercise stress testing with ECG was available for individuals with stroke (either at their facility or by referral). Most respondents across all practice settings (98.0% [432/441]) reported that they did not have access to exercise ECG equipment for their patients/clients with stroke (Table 4). Only 38.7% (161/416) of respondents were confident about all aspects of AEX prescription for individuals with stroke (Table 5). Leading areas of uncertainty were strategies to increase motivation (26.2% [109/416]), intensity (23.8% [99/416]), and strategies to increase self-efficacy (23.1% [96/416]). In addition, 54.6% (252/462) of respondents reported that they were unfamiliar with American College of Sports Medicine Guidelines for Exercise Testing and Prescription and 84.6% (391/462) reported that they were unfamiliar with AHA Physical Activity and Exercise Recommendations for Stroke Survivors. Among outpatient PT respondents, 53.7% (103/192) reported that they were not aware of any community-based programs in their area that provide supervised AEX opportunities appropriate for individuals with stroke.
AEX Dosing Parameters
The majority of PTs in all practice settings reported prescribing standing exercises (80.0%-96.6%, depending on practice setting), sitting/lying exercises (73.9%-93.1%, depending on practice setting), and over ground walking (72.7%-93.1%, depending on practice setting) for AEX among individuals with stroke (Figure 3). Other AEX modes differed between practice settings. The majority of nonacute care PTs reported prescribing some form of ergometry (65.5%-94.6%, depending on practice setting). The majority of inpatient rehabilitation (67.4% [31/46]) and home health (53.5% [31/58]) PTs reported prescribing stair climbing. The majority of outpatient PTs (56.2% [100/178]) reported prescribing treadmill walking/jogging.
To determine the initial AEX intensity for individuals with stroke, 99.2% (383/386) of respondents reported using at least 1 subjective method, 79.5% (307/386) reported using at least 1 target HR method and 32.6% (126/386) reported using at least 1 target workload method (additional details in Table 6). Light intensity was the most commonly prescribed intensity reported by acute care and outpatient PTs, while moderate intensity was the most common in other practice settings (Table 7). The volume of prescribed AEX for individuals with stroke is described in Table 8. Some volume parameters differed significantly between several practice settings, so ranges are reported across practice settings. Median AEX volume ranged from 20 to 30 minutes, 3 to 5 times per week for 2 to 8 weeks.
AEX Safety Considerations
To screen for safety before prescribing AEX for individuals with stroke, 22.7% (96/423) of respondents reported using some type of exercise test, 0.0% to 11.5% (depending on practice setting) reported using an exercise ECG, 73.5% to 92.2% (depending on practice setting) reported using HR response to exercise, and 70.5% (298/423) reported using BP response to exercise (Table 9). A quarter of respondents (25.0% [116/465]) believed that an exercise ECG stress test was needed for individuals with stroke before prescribing AEX and only (1.8% [7/398]) had stress test results for the majority of their patients/clients (Table 10). To monitor for safety during AEX for individuals with stroke, 89.3% (341/382) of respondents reported monitoring HR, 75.9% (290/382) reported monitoring BP, and 0.0% to 14.3% (depending on practice setting) reported monitoring ECG (Table 11).
Regarding serious adverse events observed during or immediately after AEX, 9.9% (43/436) of respondents reported having witnessed at least 1 individual with stroke having a cardiac event (myocardial infarction or cardiac arrest) and 11.0% (48/437) of respondents reported having witnessed at least 1 individual having a recurrent stroke.
This survey aimed to assess AEX prescription for individuals with stroke among US PTs currently involved with clinical stroke rehabilitation. Although most respondents believed that AEX should be incorporated into rehabilitation programs for individuals with stroke, several barriers to routine AEX prescription were identified. These barriers included institutional characteristics (eg, lack of time, staff, equipment, and safety screening methods), patient/client characteristics (eg, limited ability and motivation to exercise at a training level, cognitive/perceptual impairments, and balance impairments), safety concerns, lack of familiarity with AEX guidelines/recommendations, and limited availability of stress testing and community-based AEX opportunities for individuals with stroke after rehabilitation discharge.
Despite these barriers, our survey results indicate that the majority of PTs across all practice settings appear to be prescribing at least the minimum recommended AEX session duration and frequency for individuals with stroke (20 minutes, 3 days per week).8 However, median total duration of prescribed AEX ranged from 2 to 8 weeks across practice settings and these durations are shorter than those used in most previous AEX studies (3-6 months)9–16 and recommendations.8 Greater availability and awareness of community-based programs for persons with stroke to continue AEX after rehabilitation discharge could help extend these total durations and make AEX a lifelong habit after stroke.31
One of the most common areas of uncertainty reported by respondents was in prescribing AEX intensity, and this variable is a critical determinant of AEX safety and efficacy.32,33 While moderate- to vigorous-intensity AEX is recommended during the rehabilitation phase of stroke recovery,8 light intensity (eg, <40% HR reserve) was the most commonly prescribed intensity among outpatient PTs and was also common in other settings. This intensity is generally not considered to be AEX,19,20 nor to require a preexercise stress test.8,33 Therefore, it is possible that PTs are commonly prescribing light intensity because of safety concerns or limited availability of stress testing or ECG monitoring. It is also important to note that respondents reported primarily using subjective methods to determine AEX intensity and primarily based target HR calculations on age-predicted HR max, rather than on an exercise test. This practice increases the difficulty of determining AEX intensity with certainty.32,33
Although ECG stress testing is recommended before initiating AEX among persons with stroke,8 only 2% of nonacute care PT respondents reported having results from an ECG stress test or monitoring an ECG during initial AEX sessions for the majority of patients/clients. Remarkably, this number is identical to the number of respondents who reported using stress testing in a previous survey of Canadian PTs involved with neurologic rehabilitation.22 Based on responses to the rest of our survey, this low utilization of ECG testing is most likely related to the use of light-intensity exercise and/or the limited availability of stress testing and exercise ECG equipment. In addition, the low utilization of ECG testing also appears to be related to a prevalent belief that it is not needed. For example, 69% of nonacute care PT respondents believed that neither stress testing nor ECG monitoring is necessary for most individuals with stroke. This belief is inconsistent with AEX guidelines34 and stroke-specific AEX recommendations8,18 and could lead to safety issues. For example, a previous study that involved ECG stress testing on 98 consecutive individuals with stroke identified previously unknown clinically relevant abnormalities in 11 individuals, including 6 persons with no history of coronary artery disease.35 Continuing education programming emphasizing these data and poststroke AEX recommendations could help increase utilization of ECG stress testing.
However, it has also been recognized that stress testing is not available in all settings (eg, rural areas) and that avoiding AEX in these situations may itself present a health risk. For example, AHA recommendations state that individualized AEX prescription should not be delayed if stress testing is not feasible or the individual's physician determines it is not indicated.8 Unfortunately, no stroke studies have directly evaluated the relative safety of AEX compared to AEX avoidance in the absence of baseline ECG testing. Given the results of this survey, this is clearly an area where more research is needed to inform best practices.
In our survey, 10% of respondents reported that they had witnessed a person with stroke having a myocardial infarction or cardiac arrest in temporal proximity to AEX and 11% reported that they had witnessed a temporally related recurrent stroke. These rates are not entirely surprising, given that persons with stroke have a high risk of myocardial infarction (3%-5% incidence per year) and recurrent stroke (∼30% lifetime incidence).8 Furthermore, it is well established that AEX can precipitate plaque disruption or ventricular arrhythmias in a small number of susceptible individuals.8,36 However, the percentages reported on this survey do seem to be rather high since the typical rate of exercise-related serious cardiac events in cardiac rehabilitation is only 1 per 81 670 exercise hours.34 In addition, previous stroke studies have not reported any serious cardiac events or recurrent strokes related to AEX.37 Both cardiac rehabilitation and poststroke AEX studies generally involve medical screening, baseline ECG stress testing, and/or ECG monitoring during initial AEX sessions. Therefore, it is possible that the rates of serious adverse events reported by survey respondents could be reduced by increasing the frequency of these safety practices in clinical stroke rehabilitation. It is also important to remember that long-term AEX reduces the risk of cardiovascular events8,36 and the benefits of AEX are widely considered to outweigh the risks,36 including after stroke.8
Data from this survey estimate that about half of licensed PTs (568 out of 1212) are currently involved with clinical stroke rehabilitation to some degree. This large proportion speaks to the high incidence and prevalence of stroke,7 as well as the importance of PTs in the stroke recovery process. However, our data also indicate that most PTs involved with stroke rehabilitation are likely not focused on this practice area, as only 22% reported being primarily engaged in the neuromuscular practice pattern. Specialization could make it easier to keep up with current best-practice recommendations and stroke-related continuing education or to establish relationships to facilitate comprehensive and integrated stroke care (eg, referrals for stress testing, transitions to community-based AEX programs appropriate for individuals with stroke). Future studies are needed to determine whether PT specialization and continuing education have an impact on stroke recovery outcomes.
The primary limitation to this study is the low response rate (3.7%). While it is possible that the response rate in the population of interest (PTs currently involved in clinical stroke rehabilitation in common practice settings) was higher, there is no way to know how many survey invitations were sent to PTs meeting these criteria. The low response rate may have been partially related to survey fatigue, because states were sampled where e-mail address listings of licensed PTs were publicly available at no cost. Therefore, PTs in these states may receive many survey and solicitation e-mails. Yet despite this low response rate, the number of responses received (n = 1212) and analyzed (n = 568) was larger than that in previous related studies (n = 155-230)22,31 and respondents appeared to be representative of the US PT workforce. One exception was that PTs with 0 to 10 years of licensure were somewhat underrepresented. However, sensitivity analyses indicated that this likely had minimal impact on the results. It is possible that respondents may have been more favorable to AEX prescription than nonrespondents. To decrease this possibility, the e-mail invitation specifically asked PTs to participate even if they did not typically prescribe AEX. Another limitation to this study is the possibility of response bias. Although all questions were posed with neutral, nonjudgmental phasing, respondents might have answered some questions in a manner anticipated to please the researchers.38 This tendency could have artificially inflated the results regarding AEX utilization, dosing, and safety practices.
Results of this survey study indicate that most US PTs believe AEX should be incorporated within stroke rehabilitation. However, several barriers to routine AEX prescription were identified. While most PTs reported prescribing the recommended AEX session duration and frequency, reported intensity and total duration of AEX were generally lower than recommended and the use of exercise testing was very limited. In terms of research, studies are needed to identify the best ways to address the identified barriers. More specific clinical guidelines for poststroke exercise testing and training may also be beneficial. For PT education, greater focus on the application of exercise physiology principles to rehabilitation could help. In clinical practice, greater collaboration between stroke and cardiac rehabilitation teams would likely facilitate better adherence to poststroke AEX recommendations.
The authors thank Dr Ada Tang and physical therapist focus group participants for their assistance with survey development and Jennifer Westover for her assistance with data management.
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