Janice J. Eng, Kelly S. Chu, Andrew S. Dawson, C.Maria Kim and Katherine E. HepburnMyocardial Exertion

Functional Walk Tests in Individuals With Stroke: Relation to Perceived Exertion and

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Functional Walk Tests in Individuals With StrokeRelation to Perceived Exertion and Myocardial Exertion

Janice J. Eng, PhD, PT/OT; Kelly S. Chu, MSc; Andrew S. Dawson, MD, FRCPC;C. Maria Kim, MSc, PT; Katherine E. Hepburn, BHK

Background and Purpose—Functional walk tests such as the 6- and 12-Minute Walk Test (ie, 6MWT and 12MWT,respectively) are submaximal measures used to determine functional capacity in individuals with compromised ability.The purpose of this study was to determine the relationship between these walk tests and measures of exertion (perceivedand myocardial), in addition to impairment in individuals with stroke. The relationship among the 6MWT, 12MWT, andthe more traditionally assessed measure of self-paced gait speed (generally assessed over a short distance, eg, 10 m) wasalso evaluated.

Methods—Twenty-five community-dwelling individuals with stroke were evaluated for the following: 12MWT distance,6MWT distance, self-paced gait speed over 8 m, plantarflexion strength, Berg Balance Scale, Ashworth Scale ofSpasticity, and Chedoke-McMaster Stroke Assessment. Heart rate (HR), rate-pressure product (RPP), and perceivedexertion were assessed during the functional walk tests. Correlational analysis quantified the relationship between gait,impairment measures, and physiological responses during the functional walk tests.

Results—HR reached a steady state after 6 minutes and reflected a moderate exercise intensity of 63% of age-predictedmaximum HR. The 6MWT, 12MWT, and self-paced gait speed were all highly correlated with one another (r�0.90)and were all also related to the severity of impairments. The functional walk distances did not relate either to perceivedexertion or actual exertion (increase in the myocardial oxygen demand as measured by RPP).

Conclusions—Stroke-specific impairments are the major limitations to the distance walked in individuals with stroke. Ifthe functional walk test is used to assess performance of an individual over time (eg, in response to an intervention),we recommend that both exertion (eg, increase in RPP or HR) and distance be measured. (Stroke. 2002;33:756-761.)

Key Words: exercise � gait � outcome assessment � stroke

Functional walk tests such as the 6- and 12-Minute WalkTest (ie, 6MWT and 12MWT, respectively) are submaxi-

mal measures that are often used to determine functionalcapacity in individuals with compromised ability. Functionalcapacity has been defined as the extent to which a person canincrease exercise intensities and maintain those increasedlevels.1 Thus, functional walk tests differ from the standardself-paced gait speed evaluation (eg, over 8 m) in theirrequirement for sustained walking activity over extendedperiods of time.

There has been a recent trend toward more intensiveexercise programs (eg, treadmill walking or circuit training)in acute and chronic stroke populations,2–6 and it would betimely to reexamine some of the current outcome measuresused to evaluate these programs. Although measures such asmaximum oxygen consumption provide important measuresof cardiovascular fitness, functional walk tests have also beenused to evaluate intensive programs2,3 because they requirethe individual to sustain a submaximal intensity at an inten-

sity and duration that might better reflect activities of dailyliving in this population. In fact, Poulin et al7 assessed theeffects of a 9-week endurance training program in older menand found that a 280% improvement in endurance time at asubmaximal level was accompanied by only a 10% increasein maximum oxygen consumption. In addition, not all sub-jects may be able to tolerate maximal exercise testing; Peetersand Mets8 found that 22% of their elderly patients withchronic heart failure were unable to complete a standardtreadmill test.

Functional walk tests were originally developed for car-diorespiratory and cardiovascular populations.9,10 In thesepopulations, it has been shown that walk distances of both the6MWT and 12MWT were related to gait speed measuredover short distances.11 However, Duncan et al12 pointed outthat one of the problems with current stroke outcome mea-sures is that these measures were not always developedspecifically for stroke. For example, there are a number ofstroke-specific impairments that could potentially alter the

Received October 18, 2001; final revision received December 3, 2001; accepted December 6, 2001.From the School of Rehabilitation Sciences (J.J.E., K.S.C., C.M.K.), University of British Columbia, and the Rehabilitation Research Laboratory

(J.J.E., K.S.C., C.M.K., K.E.H.) and Acquired Brain Injury Program (A.S.D.), GF Strong Rehabilitation Centre, Vancouver, BC, Canada.Reprint requests to Dr Janice Eng, School of Rehabilitation Sciences, University of BC, T325-2211 Wesbrook Mall, Vancouver, BC, Canada V6T 2B5.

E-mail janicee@interchange.ubc.ca© 2002 American Heart Association, Inc.

Stroke is available at http://www.strokeaha.org

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outcome of the functional walk tests. Individuals with strokemay be limited by cardiovascular performance; however,factors such as muscle weakness (from peripheral and centralorigin),13–16 balance impairment,14,16 and spasticity17 couldpotentially influence the distance walked. Given these differ-ences, even commonly held assumptions regarding the use offunctional walk tests (eg, the 6MWT has predictive valuesimilar to that of the 12MWT) should be verified forindividuals with stroke.

The purpose of the present study was to determine therelationship among the 6MWT, 12MWT, and the moretraditionally assessed measure of self-paced gait speed (as-sessed over a short distance, eg, 8 m). In addition, therelationship between these walk tests and measures of im-pairment and exertion were assessed. The following questionswere addressed for individuals with stroke: (1) How dofunctional walk tests relate to perceived exertion as measuredby the Borg Scale18 and myocardial exertion as indicated bythe rate-pressure product (RPP)? (2) How does the heart rate(HR) response to functional walk tests relate to maximumage-predicted exertion levels and to HR levels predicted byratings of perceived exertion? (3) Do the functional walk testsrelate to measures of physical impairment, including balance,muscle strength, and spasticity? (4) What is the relationshipbetween self-paced gait speed, 6MWT, and 12MWT, and dofunctional walk tests provide additional information com-pared with the standard self-paced gait speed?

MethodsStudy ParticipantsTwenty-five community-dwelling individuals with stroke and resid-ual unilateral weakness were recruited on a volunteer basis. Inclusioncriteria were as follows: (1) a history of cerebrovascular accident ofat least 1 year after stroke, (2) independent ambulation with orwithout an assistive device, and (3) written permission to participatein the study from a primary care physician. Participants wereexcluded if they had any of the following: (1) comprehensiveaphasia, (2) medical instability (ie, uncontrolled hypertension, ar-rhythmia, or unstable cardiovascular status), (3) significant muscu-loskeletal problems from other than stroke, or (4) a score of �24 onthe Folstein Mini-Mental State Test.19 Participants provided theirinformed consent, and approval was obtained from the university andhospital ethics committees.

Protocol

Practice SessionsTo minimize practice effects,20,21 one practice trial of (1) 12MWT,(2) 6MWT, (3) self-paced gait speed over 8 m, (4) plantarflexionstrength, and (5) Berg Balance Scale was undertaken for 3 separatepractice days before the test sessions.

Test SessionsTest sessions were undertaken for 3 days for the 5 tasks: 12MWT,6MWT, self-paced gait speed over 8 m, plantarflexion strength, andBerg Balance Scale. The 12MWT and 6MWT were performed onseparate days with one half of the subjects performing the 12MWTfirst and the other half performing the 6MWT first. In addition, on 1of the 3 days, the lower extremity component of the Chedoke-McMaster Stroke Assessment was measured to determine the pres-ence and severity of lower limb physical impairments; this measurehas been shown to be valid and reliable in individuals with stroke.22

As well, the Ashworth Scale for the leg and foot was used to measureone component of spasticity, ie, the resistance to passivemovement.23

All walking tests were completed with subjects wearing theirshoes and usual assistive devices (eg, cane, ankle-foot orthosis).Self-paced gait speed was calculated from the mean of 3 walkingtrials. The cumulative distance and time of consecutive strides (ie,from foot contact with one leg to the next foot contact with the sameleg) were recorded by infrared-emitting diodes (Northern Digital)attached to the foot during the middle section (ie, an �4-m sectionrepresentative of constant gait speed) of the 8-m walkway.

For the functional walk tests, subjects were instructed to “walk asfar as possible around a 42-m rectangular path within the given time(6 or 12 minutes) and not to stop unless they needed to,”24 and thetotal distance was measured. HR (Polar Electro Inc) was recordedevery 2 minutes during the functional walk tests, and blood pressure(BP) was recorded (A&D Engineering Inc) before and at the end ofthe functional walk tests. RPP, a measure of myocardial oxygendemand, was calculated as the product of HR and systolic BP.Subjects were asked how hard they perceived that they were workingduring the test on the 16-point Borg Rating of Perceived Exertion(RPE) scale17 (1) before starting the functional walk test, (2) duringthe last 10 seconds of the 6MWT, and (3) at the 6-minute point of the12MWT and during the last 10 seconds of the 12MWT.

All gait variables (self-paced gait speed and functional walkdistances) were normalized to leg length. We have previouslyevaluated the test-retest reliability (separate days) for 22 individualswith stroke and found the intraclass correlation to be 0.99 for the12MWT distance and 0.95 for self-paced gait speed.

Plantarflexion strength was selected to measure peripheralstrength because the plantarflexion push-off phase is the singlelargest mechanical power phase during normal gait.25 Three trials ofisokinetic plantarflexion strength (average torque normalized tobody mass) of the paretic and nonparetic ankle were assessed at 30°/son a KinCom strength dynamometer (Chattanooga Inc Corp). Thisprotocol has been reported previously and has been found to bereliable in individuals with stroke.21

Balance was assessed by using the Berg Balance Scale. This test,composed of 14 tasks of sitting and standing activities, has beenshown to be a valid and reliable measure of balance in stroke.26,27 Ofthe 25 subjects, 10 walked with a cane, and 9 subjects used anankle-foot orthosis.

Statistical MethodsDescriptive statistics were performed for all variables measured.Pearson product moment correlations quantified the relationshipbetween (1) gait (self-paced, 6MWT, and 12MWT) and impairmentmeasures (Chedoke-McMaster lower extremity impairment score,Berg Balance Scale, plantarflexion strength, and spasticity) and (2)gait and exertion measures (RPE and RPP). In addition, Pearsonproduct moment correlations among the 3 gait measures (6MWT,12MWT, and gait speed) were undertaken. HR at the end of thefunctional walk tests was compared with the predicted HR based onperceived exertion (RPE multiplied by 10) by paired t test andPearson product moment correlations. Statistical analyses wereperformed with SPSS 9.0 (SPSS Inc), with a significance level set atP�0.05 (2-tailed).

ResultsSubject characteristics, impairment measures and gait data,and physiological responses during walk tests are presentedin Tables 1, 2, and 3, respectively. Subjects were currentlytaking prescribed medications to control for hypertension (ie,peripheral vasodilators, n�6; diuretics, n�6; and ACE inhib-itors, n�15) and preexisting cardiac conditions (ie,�-blockers, n�3; antiarrhythmic agents, n�1). Seven partic-ipants were on antidepressants.

Distance for 6MWT and 12MWTFor both test distances (6MWT and 12MWT), subjectscovered similar distances over each 2-minute segment, with

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only a 2% and 3% reduction in distance from the first to thelast 2-minute segment for the 6MWT and 12MWT, respec-tively (Figure). Despite the knowledge of a longer exerciseduration required for the 12MWT, subjects paced themselvesidentically, with a mean distance of 268 m in the first 6minutes of both functional walk tests. The distances calcu-lated by using the self-paced gait speed for the 6MWT and12MWT (gait speed multiplied by 6 or 12 minutes) were287.4 and 574.9 m, respectively. These values overestimatedthe actual distance covered for the 6MWT (by 7%) and for the12MWT (by 8%). Given that the gait speed during the walktest was relatively constant, subjects paced themselves moreslowly during the functional walk tests.

Physiological ResponsesFor both functional walk tests, a large increase in HR (36%and 30% for the 6MWT and 12MWT, respectively) occurred

during the first 2 minutes. Then, for the next 4 minutes (fromtime 2 to 6 minutes), there was a small increase (�7%) in HRfor both walk tests. During the last 6 minutes of the 12MWT,there was virtually a plateau in HR, with only a 1% increase(Figure).

HR climbed to a mean maximum of 100.4 bpm for the6MWT and 101.5 bpm for the 12MWT. This HR reflects anexercise intensity of 63�9.0% (range 50% to 86%) and64�10.8% (range 49% to 93%) of age-predicted maximalHR (220 bpm minus age) for the 6MWT and 12MWT,respectively.

Actual Exertion Versus Perceived ExertionActual exertion, assessed by using the RPP (ie, HR�SBP),which is an indication of the myocardial oxygen demand,increased 57% and 56% from the start to the end of the 6MWTand 12MWT, respectively. This increase of RPP (in addition tothe increase in HR and increase in systolic BP) was notcorrelated with the functional walk distance (Table 4).

The mean perceived exertion at the 6-minute point for bothtests were similar (RPE 11), whereas the RPE rose anadditional 2 points over the last 6 minutes of the 12MWT.The RPE scale was developed such that the corresponding

TABLE 2. Impairment and Gait Measures (25 Subjects)

Variable Mean SD

Chedoke-McMaster lower extremity score* 8.9 2.4

Berg Balance Scale† 49.2 3.5

Ashworth Scale‡ 1.0 1.1

Plantarflexion strength, Nm/kg

Paretic limb 0.29 0.24

Nonparetic limb 0.95 0.26

Gait speed

Self-selected, m/s 0.80 0.26

Gait speed normalized to leg length, s�1 1.06 0.36

6MWT distance, m 267.7 89.7

6MWT distance, normalized to leg length 354.0 105.5

12MWT distance

Minutes 0–6, m 267.7 93.2

Minutes 0–6, normalized to leg length 487.3 160.6

Minutes 6–12, m 262.8 92.3

Minutes 6–12, normalized to leg length 352.0 119.5

Total, m 530.5 184.9

Total, normalized to leg length 752.7 252.0

*Maximum Chedoke-McMaster lower extremity score is 12.†Maximum Berg Balance score is 56.‡Maximum leg and ankle Ashworth score is 10.

TABLE 3. Physiological Responses During the Functional WalkTests (25 Subjects)

Mean SD

RPE

6MWT 11.6 3.2

12MWT

Minute 6 11.7 2.9

Minute 12 13.4 3.8

HR, bpm

6MWT

Rest 71.4 9.2

Minute 6 100.4 15.7

12MWT

Rest 72.8 12.0

Minute 6 100.4 16.6

Minute 12 101.5 19.0

SBP/DBP, mm Hg

6MWT

Rest 128.4/78.9 16.5/10.3

Minute 6 144.1/81.1 21.8/10.3

12MWT

Rest 131.0/80.2 18.2/11.8

Minute 12 145.7/81.4 23.2/11.9

RPP (HR�SBP�10�2)

6MWT

Rest 9.2 1.6

Minute 6 14.4 3.3

12MWT

Rest 9.5 2.1

Minute 12 14.9 4.1

SBP indicates systolic BP; DBP, diastolic BP.

TABLE 1. Subject Characteristics (25 Subjects)

Variable Mean SD Range

Sex (male/female), n 17/8

Type of stroke(ischemic/hemorrhage/unknown), n

12/11/2

Hemiparetic side (left/right), n 13/12

AHASFC (I/II/III), n 11/12/2

Age, y 62.6 8.5 50–82

Time since stroke, y 4.4 3.0 1–11

Mass, kg 76.4 15.9 52.1–113.9

Height, cm 166.2 12.2 143–185

Body mass index, kg/m2 27.6 4.7 17.9–38.5

AHASFC indicates American Heart Association Stroke Functional Classifica-tion.

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HR can be predicted by multiplying the RPE by 10.28 Thepredicted HR based on the RPE at the end of the functionalwalk test was significantly higher (P�0.05) than the actualHR (15% and 32% higher for the 6MWT and 12MWT,respectively). In addition to the discrepancy in magnitudebetween the predicted HR (based on RPE) and the actual HR,the correlation between these 2 measures was not significantfor either functional walk test.

Correlations of Gait Measures With SubjectCharacteristics and ImpairmentsAll walking measures (functional walk distances and self-paced speed) were correlated with balance function (r�0.78to 0.80), Chedoke-McMaster impairment score (r�0.69 to0.76), plantarflexion strength of the paretic side (r�0.42 to0.54), and spasticity (�0.42 to �0.53) (Table 4). Further-more, all walking measures were highly correlated with oneanother (Table 4), with a 0.97 correlation between the 6MWT

and 12MWT. The functional walk distances could be pre-dicted by the following equations: (1) 6MWT distance(m)�320.9�(gait speed in m/s)�11.7; (2) 12MWT distance(m)�655.4�(gait speed in m/s)�7.2; and (3) 12MWT dis-tance (m)�2.02�(6MWT distance in meters)�10.6.

DiscussionFunctional walk distances were very low and were �60% ofthe values reported for chronic respiratory subjects10 and only42% to 50%29–31 of those reported for older adults. The veryslow pace of these subjects serves as a caution whenattempting to understand the mechanisms underlying theirfunctional walk performance compared with establishedhealthy normative values or with results from other patho-logical groups.

Physiological Workload During the Walk TestsAll but 1 subject in the present study remained within the85% of age-predicted maximum HR that is recommended asthe upper limit for submaximal exercise testing.32 The indi-vidual who reached levels closest to his maximum HR wasone of the most impaired subjects and had the lowest balancescore, greatest spasticity, and measures reflecting the slowestgait speeds.

Endurance has been defined as the time limit of a person’sability to sustain a particular level of physical effort,1,33 and areduction in speed over the test would have indicated thatendurance was challenged during this test. The intensity ofthe exercise can be classified as moderate according to theHR32 (mean 63% of age-predicted maximum HR), andsubjects sustained their levels of physical effort with only a2% to 3% decrease in gait speed over the test with a steadystate in HR attained at 6 minutes. Given the minimalreduction in speed over the test, it is not possible to determineto what extent that endurance was challenged. However,Dean et al34 suggested that individuals with stroke sloweddown during the 6MWT because they found that the self-paced gait speed multiplied by a 6-minute time intervaloverestimated the actual 6MWT distance covered. In con-trast, our cohort did not slow down but, in fact, pacedthemselves at a slower gait speed, which was maintainedthroughout the functional walk test. Although some investi-gators have used the 6MWT to provide an outcome measureof endurance in individuals with stroke,2,3 we believe thatthese walk tests better represent a measure of functionalcapacity.

The nonsignificant correlation between the RPP and dis-tance walked is in contrast with the results from Fitts andGuthrie,35 who reported a strong positive correlation betweenthe increase in HR and 6MWT distance in individuals withchronic renal failure (r�0.81). This discrepancy is likely dueto the mechanical inefficiency of gait in persons with stroke,which could vary depending on the severity and the combi-nation of impairments. For example, the metabolic cost ofwalking has been found to be related to the degree ofspasticity.17 It is also possible that the subjects’ medicationscould affect the myocardial response to exercise; however,ACE inhibitors and �-blockers have been reported to have

HR, RPE, and distance covered during the 6MWT and 12MWT.HR at every 2 minutes (squares), distance covered for each2-minute segment (circles), and RPE before and at the end ofeach test, in addition to the 6 minute point of the 12MWT (trian-gles), are shown. Solid symbols indicate 12MWT, and opensymbols indicate 6MWT.

TABLE 4. Correlations Between Gait Variables andImpairment, Perceived Exertion, and Myocardial Exertion (RPP)(25 Subjects)

6MWTDistance

12MWTDistance

GaitSpeed

Impairment

Chedoke-McMaster Stroke Assessment 0.754* 0.689* 0.757*

Berg Balance score 0.784* 0.798* 0.784*

Spasticity (Ashworth score) �0.534* �0.422† �0.452†

Paretic plantarflexion strength 0.425† 0.352 0.537*

Nonparetic plantarflexion strength �0.217 �0.169 �0.232

Exertion

RPE �0.10 �0.06

RPP �0.237 �0.224

Gait

Self-selected gait speed 0.920* 0.914*

12MWT distance 0.966*

RPP indicates change in RPP (HR�SBP) at end of 12 minutes. Allcorrelations were performed by using gait variables normalized to leg length.

*P�0.01; †P�0.05.

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minimal effect on the change in HR and systolic BP36 duringsubmaximal exercise.

Perceived Exertion and Relation to HR DuringWalk TestsRatings of perceived exertion are generally believed to bevalid and reliable markers of physiological intensity duringexercise37 and are recommended to monitor exercise intensi-ty.32 A higher RPE has been reported to be related to a shorter12MWT distance in individuals with respiratory disease(r��0.59),10 suggesting that more severely impaired sub-jects perceive greater exertion. However, the lack of correla-tion between RPE and distance walked or between predictedHR based on RPE and actual HR suggests that further studiesto identify factors influencing perceived exertion in the strokepopulation are needed. Given the lack of correlation, inaddition to the overestimation of exercise HR based on RPE,individuals with stroke should not rely solely on RPE whentrying to gauge exercise intensity in relation to HR.

A variety of physiological, pharmacological, psychologi-cal, and performance factors could potentially elevate theperception of physical exertion. Seventeen of 25 subjectswere taking ACE inhibitors and �-blockers, which have beenshown to increase perceived exertion during submaximalexercise, possibly because of their effect on contractilemuscle function.36 We postulate that the increased RPE canalso be attributed to the presence of stroke-specific impair-ments (eg, muscle weakness or spasticity), which may in-crease peripheral muscular discomfort and fatigue and beperceived as requiring more exertion. Bard17 found that themetabolic cost of self-paced walking was higher in personswith stroke than in healthy individuals and was related to theseverity of impairment.

Interestingly, the major difference between the 6MWT and12MWT was in the perceived exertion, despite a stable HRand constant velocity. This concurs with other studies whichhave shown that cumulative effect contributes to increases inperceived exertion.38

Which Walk Test Should Be Used?The 0.97 correlation between the 6MWT and 12MWTdistance, in addition to the finding that HR did not increasesubstantially after 6 minutes, suggests that the 6MWT can beused in place of the longer 12MWT for individuals withstroke (Equation 3). More controversially, one could suggestthe simple use of self-paced gait speed to predict functionalwalk test performance, given that correlations were �0.90between self-paced gait speed and the functional walk tests(Equation 2). Although we found that gait speed and 6MWTprovide similar distance information, the functional walk testdoes have important value when HR and BP are monitored.The functional walk test can be described as a measure offunctional capacity that evaluates the ability of an individualto maintain a moderate level of physical activity over a timeperiod that may be reflective of the activities of daily living.Measures of RPP and RPE, together with the distancewalked, may provide an indication of an individual’s physi-ological tolerance to submaximal activity. One of the limita-tions of the functional walk test is that subjects can vary either

or both the distance and the exertion. If the functional walktest is used to assess performance of an individual over time(eg, in response to an intervention), we recommend that bothexertion (eg, increase in RPP or HR) and distance bemeasured. A ratio of exertion and distance walked may be anideal measurement, although the linearity and sensitivity ofsuch a measure need to be explored in the future. Suchmeasures are similar to the energy expenditure index39 andphysiological cost index,40 which have been used in pediatricand polio populations, respectively, to calculate the change inHR per meter walked.

Performance in the functional walk tests depends onfactors including motivation, respiratory function, cardiovas-cular fitness, neuromuscular function, and peripheral musclestrength. The high correlations between the functional walktests and impairments suggest that stroke-specific impair-ments are major limitations to the distance walked duringthese tests. The contribution of cardiovascular fitness (eg,maximum oxygen consumption) to the functional walk testperformance was not assessed, although others have reportedno or low correlations with oxygen consumption duringmaximal exercise testing in cardiovascular and respiratorypopulations.4,9,23 The physiological demands of functionalwalk tests are distinct from those of cycle ergometer ortreadmill tests and may be a better indicator of functionalcapacity required for normal daily activities.9,35

Limitations of the StudyOne limitation of the present study is that a multivariateanalysis was not undertaken because of the small sample size,although this would be a useful future avenue of research.

AcknowledgmentsThis study was supported by the BC Health Research Foundation anda grant-in-aid from the Heart and Stroke Foundation of BritishColumbia and the Yukon.

References1. Brooks GA, Fahey TD, White TP. Exercise Physiology: Human Bioen-

ergetics and Its Applications. Mountain View, Calif: Mayfield PublishingCo; 1996.

2. Dean CM, Richards CL, Malouin F. Task-related circuit trainingimproves performance of locomotor tasks in chronic stroke: a ran-domized, controlled pilot trial. Arch Phys Med Rehabil. 2000;81:409–417.

3. Duncan P, Richards CL, Wallace D, Stoker-Yates J, Pohl P, Luchies C,Ogle A, Studenski S. A randomized, controlled pilot study of ahome-based exercise program for individuals with mild and moderatestroke. Stroke. 1998;29:2055–2060.

4. Macko RF, DeSouza CA, Tretter LD, Silver KH, Smith GV, AndersonPA, Tomoyasu N, Gorman P, Dengel DR. Treadmill aerobic exercisetraining reduces the energy expenditure and cardiovascular demands ofhemiparetic gait in chronic stroke patients. Stroke. 1997;28:326–330.

5. Potempa K, Lopez M, Braun LT, Szidon JP, Fogg L, Tincknell T.Physiological outcomes of aerobic exercise training in hemiparetic strokepatients. Stroke. 1995;26:101–105.

6. Rimmer JH, Riley B, Creviston T, Nicola T. Exercise training in apredominantly African-American group of stroke survivors. Med SciSports Exerc. 2000;32:1990–1996.

7. Poulin MJ, Paterson DH, Govindasamy D, Cunningham DA. Endurancetraining of older men: responses to submaximal exercise. J Appl Physiol.1992;73:452–457.

8. Peeters P, Mets T. The 6-minute walk as an appropriate exercise test inelderly patients with chronic heart failure. J Gerontol. 1996;51:M147–M151.

760 Stroke March 2002

at University of Utah on October 10, 2014http://stroke.ahajournals.org/Downloaded from

9. Guyatt GH, Sullivan MJ, Thompson PJ, Fallen EL, Pugsley SO, TaylorDW, Berman LB. The 6-minute walk: a new measure of exercise capacityin patients with chronic heart failure. Can Med Assoc J. 1985;132:919–923.

10. McGavin CR, Artvinli M, Naoe H, McHardy GJ. Dyspnoea, disabilityand distance walked: a comparison of estimates of exercise performancein respiratory disease. Br Med J. 1978;2:241–243.

11. Butland RJA, Pang J, Gross ER, Woodcock AA, Geddes DM. Two-, six-,and 12-minute walking tests in respiratory disease. Br Med J. 1982;284:1607–1608.

12. Duncan PW, Jorgensen HS, Wade DT. Outcome measures in acute stroketrials: a systematic review and some recommendations to improvepractice. Stroke. 2000;31:1429–1438.

13. Nadeau S, Gravel D, Arsenault AB, Bourbonnais D. Plantarflexorweakness as a limiting factor of gait speed in stroke subjects and thecompensating role of hip flexors. Clin Biomech. 1999;14:125–135.

14. Hamrin E, Eklund G, Hillgren A, Borges O, Hall J, Hellstrom O. Musclestrength and balance in post-stroke patients. Up J Med Sci. 1982;87:11–26.

15. Bohannon RW, Andrews W. Correlation of knee extensor muscle torqueand spasticity with gait speed with patients with stroke. Arch Phys MedRehabil. 1990;71:330–333.

16. Bohannon RW. Selected determinants of ambulatory capacity in patientswith hemiplegia. Clin Rehabil. 1989;3:47–53.

17. Bard G. Energy expenditure of hemiplegic subjects during walking. ArchPhys Med Rehabil. 1963;44:368.

18. Borg G. Perceived exertion as an indicator of somatic stress. Scand JRehabil Med. 1970;2:92–98.

19. Folstein MF, Folstein SE, McHugh PR. “Mini-mental state”: a practicalmethod for grading the cognitive state of patients for the clinician.J Psychiatr Res. 1975;12:189–198.

20. Cahalin LP, Mathier MA, Semigran MJ, Dec GW, DiSalvo TG. Thesix-minute walk test predicts peak oxygen uptake and survival in patientswith advanced heart failure. Chest. 1996;110:325–332.

21. Eng JJ, Kim CM, MacIntyre DL. Reliability of lower extremity strengthmeasures in persons with chronic stroke. Arch Phys Med Rehabil. Inpress.

22. Gowland C, Stratford P, Ward M, Moreland J, Torresin W, Van HullenaarS, Sanford J, Barreca S, Vanspall B, Plews N. Measuring physicalimpairment and disability with the Chedoke-McMaster StrokeAssessment. Stroke. 1993;24:58–63.

23. Pandyan AD, Johnson GR, Price CI, Curless RH, Barnes MP, Rodgers H.A review of the properties and limitations of the Ashworth and modifiedAshworth Scales as measures of spasticity. Clin Rehabil. 1999;13:373–383.

24. McGavin CR, Gupta SP, McHardy GJR. Twelve-minute walking test forassessing disability in chronic bronchitis. Br Med J. 1976;1:822–823.

25. Eng JJ, Winter DA. Kinetic analysis of the lower limbs during walking:what information can be gained from a three dimensional model?J Biomech. 1995;28:753–755.

26. Berg K, Wood-Dauphinee S, William JI, Gayton D. Measuring balance inthe elderly: preliminary development of an instrument. Physiother Can.1989;41:304–311.

27. Berg K, Maki BE, Williams JI, Holliday J, Wood-Dauphinee SL. Clinicaland laboratory measures of postural balance in an elderly population.Arch Phys Med Rehabil. 1992;73:1073–1080.

28. Borg GAV. Psychophysical bases of perceived exertion. Med Sci SportsExerc. 1982;14:377–381.

29. Gibbons WJ, Fruchter N, Sloan S, Levy RD. Reference values for amultiple repetition 6-minute walk test in health adults older than 20 years.J Cardiopulm Rehabil. 2001;21:87–93.

30. Harada ND, Chiu V, Stewart AL. Mobility-related function in olderadults: assessment with a 6-minute walk test. Arch Phys Med Rehabil.1999;80:837–841.

31. Troosters T, Gosselink R, Decramer M. Six minute walking distance inhealth elderly subjects. Eur Respir J. 1999;14:270–274.

32. American College of Sports Medicine. Guidelines for Exercise Testingand Prescription. 6th ed. Baltimore, Md: Williams and Wilkins; 2000.

33. McArdle WD, Katch FI, Katch VL. Exercise Physiology. Energy,Nutrition and Human Performance. 4th ed. Baltimore, Md: Williams andWilkins; 1996.

34. Dean CM, Richards CL, Malouin F. Walking speed over 10 metresoverestimates locomotor capacity after stroke. Clin Rehabil. 2001;15:415–421.

35. Fitts SS, Guthrie MR. Six-minute walk by people with chronic renalfailure: assessment of effort by perceived exertion. Am J Phys MedRehabil. 1995;80:837–858.

36. Derman EW, Sims R, Noakes TD. The effects of antihypertensive med-ications on the physiological response to maximal exercise testing. J Car-diovasc Pharmacol Ther. 1992;19:S122–S126.

37. Skinner JS, Hutsler R, Bergsteinova V, Buskirk ER. The validity andreliability of a rating scale of perceived exertion. Med Sci Sports Exerc.1973;5:94–96.

38. Wenos KL, Wallace JP, Surburg PR, Morris HH. Reliability and com-parison of RPE during variable and constant exercise protocols performedby older women. Int J Sports Med. 1996;17:193–198.

39. Rose J, Gamble JG, Burgos A, Medeiros J, Haskell WL. Energy expen-diture index of walking for normal children and for children with cerebralpalsy. Dev Med Child Neurol. 1990;32:333–340.

40. MacGregor J. Rehabilitation ambulatory monitoring. In: Kenedi RM,Paul SP, Hughes J, eds. Disability. London, UK: MacMillan; 1979:159–172.

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