non - straight steps 
 that change the direction of movement account for 3550% of all steps when walking 
 indoors1 . patients with stroke fall not 
 only during walking but also during standing turn or transfer between bed and 
 wheelchair2 , 3 .
therefore , the ability to take multidirectional steps is important 
 for patients with stroke .
there are many clinical tests that evaluate the temporal aspects of stepping4,5,6,7 , but 
 there are few that evaluate the spatial aspects .
the maximum step length ( msl ) test is a 
 clinical test of stepping distance in which participants step to the front , side , and back 
 as far as possible with one leg , before returning to the starting position8 , 9 . 

msl values correlate significantly with clinical measures of balance in community - dwelling 
 older adults8 .
in addition , 
 community - dwelling older adults showed no significant differences in step distance between 
 the front , side , and back directions8 . 

however , differences in step distance in the three directions have not been investigated in 
 patients with stroke .
in addition , the reliability of the msl test has been investigated 
 only in the front direction and has not been investigated in the side and back 
 directions10 .
stroke causes motor 
 dysfunction , loss of coordination , and weakness of the muscles , which affect standing 
 balance and walking11 .
these features 
 would also affect step distance , and step distance would be expected to vary between limbs 
 ( paretic vs. non - paretic ) and the direction of stepping ( front , side , and back ) .
step 
 training in various directions improves balance and gait12,13,14 , and it is important for the step training to evaluate the 
 characteristics of stepping according to step direction and stepping limb .
the purposes of this study were to determine the reliability of the msl test for the side 
 and back directions , the effect of the stepping limb and step direction on step distance , 
 and the associations of step distance and stepping laterality in step distance with walking 
 ability and motor dysfunction .
we hypothesized that step distance would vary across step 
 directions and stepping limbs , and that the stepping laterality in step distance would be 
 associated with motor dysfunction and walking ability .
thirty - nine patients with chronic hemiparesis as a result of stroke sustained at least 6 
 months previously were recruited from an outpatient rehabilitation center to participate in 
 this study .
inclusion criteria were the ability to walk at least 10  m with or without a 
 walking aid or ankle - foot orthosis and the ability to follow commands .
individuals were 
 excluded if they had disturbed consciousness , dementia , or musculoskeletal conditions that 
 affect the performance of walking .
the institutional review board of the geriatrics research 
 institute and hospital approved this study and all the subjects provided their written 
 informed consent to participation .
step distances were measured for the paretic and the non - paretic limbs using the msl 
 test8 , 9 .
the subjects stepped out maximally with one leg , maintaining the 
 stance leg in the initial position , and then returned to their initial stance position in 
 one step .
participants were instructed to step out with the paretic leg and the non - paretic 
 leg in each direction , and therefore performed six stepping actions : to the front with the 
 paretic limb , to the side with the paretic limb , to the back with the paretic limb , to the 
 front with the non - paretic limb , to the side with the non - paretic limb , and to the back with 
 the non - paretic limb .
the subjects were allowed to use their 
 usual ankle - foot orthosis during the msl test .
physical impairments that might affect walking ability were evaluated using the stroke 
 impairment assessment set15,16,17 .
the motor 
 functions were assessed through hip flexion , knee extension , and foot pat ( rapid foot 
 tapping ) .
motor function was evaluated in stages from 0 to 5 , with higher scores indicating 
 better function .
this treatment - oriented 
 measure includes two static sitting balance items and eight dynamic sitting balance items . 

the static sitting balance items assess the ability to maintain the sitting position with 
 and without upper limb support .
the dynamic sitting balance items assess the ability to : 
 reach with an upper limb , lift the pelvis from a table , move the buttocks in the frontal 
 plane , move the buttocks in the sagittal plane , flex the hips individually , flex the hips 
 together , rotate the upper trunk , and flex the shoulder of the non - paretic upper limb .
the 
 maximum score is 20 , with higher scores indicating better trunk function . walking ability in the home
was evaluated using the functional ambulation category ( fac ) , 
 which includes walking on uneven terrain and walking up and down stairs19 .
walking ability was rated on the following six - point 
 scale : ( 0 ) unable to walk or requires the help of two persons to walk ; ( 1 ) ambulatory with 
 firm continuous contact with one person ; ( 2 ) ambulatory with the intermittent or continuous 
 support of one person ; ( 3 ) ambulatory on level surfaces with verbal supervision or stand - by 
 help from one person without physical contact ; ( 4 ) independent ambulation only on level 
 surfaces ; and ( 5 ) independent ambulation anywhere , including stairs .
walking ability was 
 also evaluated using gait speed in the 10-m walk test and the timed up and go ( tug ) 
 time20,21,22 . for the 10-m walk test , 
 participants walked in a straight line at a comfortable speed for 16 m , including 3-m 
 runways at the start and end of a 10-m test walkway .
gait speed was calculated from the time 
 required to walk across the 10-m walkway .
the tug time was the amount of time required to 
 stand from a seated position , walk forward 3 m , turn around , walk back to the chair , and sit 
 down .
the participants completed these tasks at a comfortable speed and used their usual 
 walking aid and ankle - foot orthosis .
the test - retest 
 reliability of the two administrations of the msl test was evaluated using the intraclass 
 correlation coefficient , model 1,1 [ icc(1,1)]23 .
step distance was compared across limbs and step directions using two - way 
 repeated - measures analysis of variance ( anova ) and the bonferroni post hoc test . for each 
 step direction ,
the difference in the step distance of the paretic and non - paretic limb was 
 calculated ( paretic limb minus non - paretic limb ) .
this stepping laterality was compared 
 across the three directions using one - way repeated - measures anova .
pearson correlation 
 coefficients were calculated for all pairwise combinations of step distance in the front , 
 side , and back directions of the two limbs .
a conservative estimate of the minimal detectable change at the 95% confidence level 
 ( mdc95 ) is 8.128  cm ( 3.2 inches)10 .
therefore , subjects were classified into three groups according to 
 the stepping laterality in step distance to the front : a paretic step distance > 8.128  cm 
 and longer than the non - paretic step distance ( longer paretic step group ) , stepping 
 laterality between 8.128  cm and 8.128  cm ( symmetric group ) , or a paretic step distance 
 > 8.128  cm and shorter than the non - paretic step distance ( longer non - paretic step group ) . 

one - way anova and tukey s post hoc tests were used to compare walking ability across the 
 three groups .
the kruskal - wallis and mann - whitney u tests with bonferroni adjustments were 
 used to compare motor impairment across the three groups .
receiver operating characteristic curves were generated to compare the diagnostic validity 
 of step distance to the front to distinguish fac 5 from fac 4 .
optimal cut - off points were 
 determined by sensitivity , specificity , positive predictive value , and negative predictive 
 value .
table 1table 1.characteristics of the subjectsmean  sdmedian [ first  third quartile]age ( years)69.99.8gender : male / female ( n)23/16duration since stroke onset ( days)1562.41182.0paretic side : right / left ( n)27/12siaship - flexion4 [ 24]knee - extension3 [ 24]foot - pat3 [ 14]fact10 [ 614]gait speed ( m / sec)0.50.3tug ( s)36.124.0fac4 [ 35]fac : functional ambulation category ; fact : functional assessment for control of 
 trunk ; tug : timed up and go test ; sias : stroke impairment assessment set shows the characteristics of the 39 subjects .
their mean ( sd ) age was 69.9 
 ( 9.8 ) years , and the duration since stroke onset was 1,562.4 ( 1,182.0 ) days .
the mean gait 
 speed in the 10-m walk test was 0.5 ( 0.3 ) m / s , and the tug time was 36.1 ( 24.0 ) s. the msl 
 test had excellent test - retest reliability ( icc(1,1 ) = 0.9390.957 ; table 2table 2.reliability and step distance in each directionicc ( 1,1)95% cistep distance ( cm)step limbstep directionlimb  directionpareticfront0.9430.895 , 0.97026.120.4n.s**n.sside0.9390.888 , 0.96820.716.9back0.9570.919 , 0.97719.117.0non - pareticfront0.9510.909 , 0.97425.124.1side0.9540.915 , 0.97620.821.3back0.9460.899 , 0.97119.119.0icc : intraclass correlation coefficients .
values are mean  sd . * * significantly 
 different according to anova ( p < 0.01 ) significantly different from 
 the front and side ( p < 0.01 ) significantly different from the side 
 and back ( p < 0.01 ) ) .
there was 
 no significant effect of stepping limb on step distance ( f = 0.735 , p = 0.483 ) , but there 
 was a significant effect of step direction ( f = 19.969 , p < 0.01 ) .
for the paretic limb , 
 front step distance was significantly longer than those of the side and back step distances 
 ( p < 0.01 ) .
for the non - paretic limb , front step distance was significantly longer than 
 those of the side and back step distances ( p < 0.01 ) .
step distances were significantly 
 correlated across all pairwise combinations of direction and side ( table 3table 3.correlation between paretic and non - paretic step distances in each 
 directionpareticnon - pareticfrontsidebackfrontsidebackpareticfront0.930**0.946**0.938**0.892**0.941**side0.931**0.896**0.914**0.893**back0.890**0.855**0.931**non - pareticfront0.955**0.966**side0.929**backvalues are pearson correlation coefficients . * * p < 0.01 ) .
there was no significant effect of step direction on the stepping laterality 
 in step distance ( f = 0.735 , p = 0.482 ) .
the stepping lateralities in the front , side , and 
 back directions were 0.9  8.6 [ 1.9 to 3.8 ] cm , 0.2  9.0 [ 3.1 to 2.8 ] cm , and 0.0  7.0 
 [ 2.3 to 2.2 ] cm , respectively ( mean  sd [ 95% confidence interval ] ) .
fac : functional ambulation category ; fact : functional assessment for control of 
 trunk ; tug : timed up and go test ; sias : stroke impairment assessment set icc : intraclass correlation coefficients .
values are mean  sd . * * significantly 
 different according to anova ( p < 0.01 ) significantly different from 
 the front and side ( p < 0.01 ) significantly different from the side 
 and back ( p < 0.01 ) values are pearson correlation coefficients . *
* p < 0.01 table 4table 4.motor function and gait abilities of the three groupslonger paretic stepgroup ( n=7)symmetricgroup ( n=26)longer non - paretic stepgroup ( n=6)grouphip - flexion3 [ 2.53.5]4 [ 24]4.5 [ 45]knee - extension2 [ 23.5]2.5 [ 24]4.5 [ 45]*foot - pad2 [ 1.52.5]3 [ 24]4.5 [ 45]fact8 [ 5.511]9.5 [ 615]13.5 [ 1114]gait speed ( m / sec)0.23 0.120.46 0.280.86 0.17**tug ( s)51.1 19.836.9 24.715.1 2.8**fac2 [ 23.5]4 [ 35]5
the subjects were classified 
 into three groups according to the stepping laterality front step distance ( longer 
 paretic step group , symmetric group , longer non - paretic step group ) .
statistically significant 
 difference between longer paretic step group and longer non - paretic step group ( p < 
 0.05 ) .
statistically significant difference between longer paretic step 
 group and symmetric group ( p < 0.05 ) . statistically significant 
 difference between longer non - paretic step group and symmetric group ( p < 0.05 ) shows the motor function and walking ability of the longer paretic step group , 
 symmetric group , and longer non - paretic step group .
gait speed , tug time , and fac were 
 better in the longer non - paretic step group than in the symmetric group and the longer 
 paretic step group .
the subjects were classified 
 into three groups according to the stepping laterality front step distance ( longer 
 paretic step group , symmetric group , longer non - paretic step group ) .
statistically significant 
 difference between longer paretic step group and longer non - paretic step group ( p < 
 0.05 ) .
statistically significant difference between longer paretic step 
 group and symmetric group ( p < 0.05 ) .
statistically significant 
 difference between longer non - paretic step group and symmetric group ( p < 0.05 ) the cut - off value of the paretic front step distance which distinguished fac 5 from fac 4 
 was 33  cm .
the sensitivity , specificity , positive predictive value , and negative predictive 
 values were 0.81 , 0.91 , 0.87 , and 0.88 , respectively . the cut - off value of the non - paretic 
 front step distance which distinguished fac 5 from fac 4 was also 33  cm .
the sensitivity , 
 specificity , positive predictive value , and negative predictive values were 0.93 , 0.91 , 
 0.88 , and 0.95 , respectively .
we investigated the reliability of the msl test and the difference in step distance between 
 the paretic and non - paretic limbs for steps to the front , side , and back .
pardo reported 
 that the test - retest reliability of the msl test in the front direction was excellent for 
 both the paretic and the non - paretic limbs10 . in this study ,
test - retest reliability was excellent in each step 
 direction ( icc > 0.900 ) .
step distance did nt differ significantly between the paretic 
 and non - paretic limb .
this indicates that patients with stroke adapt to motor 
 impairment24 , and can perform similar 
 length steps with the paretic and non - paretic limb .
on the other hand , step distances 
 significantly differed between the front , side and back directions .
it is possible that poor 
 coordination of limb segments , poor posture in stepping , the effect of visual information , 
 and insufficient experience of stepping to the side and back caused the differences in step 
 distances across directions .
we classified participants into three groups according to the stepping laterality in step 
 distance to the front , with reference to a previous study10 .
the longer non - paretic step group had better walking ability than 
 the symmetric group and the longer paretic step group .
moreover , 
 weight - bearing by the paretic limb improves gait and balance ability26 .
the step distance of the non - paretic limb indicates the 
 weight shift ability of the paretic lower limb , and good weight shift ability in the paretic 
 limb is necessary for large step distances by the non - paretic limb .
therefore , the longer 
 paretic step group had limited weight - bearing ability for the paretic limb and the longer 
 non - paretic step group had adequate weight - bearing ability for the paretic limb , indicating 
 that step distance of the non - paretic limb is important for walking ability .
on the other 
 hand , most measures of motor function of the paretic limb did nt differ among the three 
 groups .
functional mobility was nt strongly correlated with impairments of motor function in 
 the paretic - lower limb27 .
therefore , it 
 is possible that motor function of the paretic - lower limb does not affect the stepping 
 laterality in step distance between the paretic and non - paretic limbs .
however , the number 
 of participants was small , and this limits the generalizability of our results . correlations between step distances in the different directions were high .
therefore , we 
 calculated cut - off scores for the paretic front step distance and non - paretic front step 
 distance to distinguish fac 5 from fac 4 .
the cut - off score was 33  cm for the paretic front 
 step distance and non - paretic front step distance .
fac can discriminate independent walkers , 
 and thus step distance to the front is useful because it can rapidly be evaluated in small 
 spaces .
a limitation of this study is that participants had chronic hemiparesis , and most had low 
 walking ability .
therefore , our results might not be reflected by stroke patients with good 
 walking ability .
in addition , it is possible that the classification of the subjects into 
 three groups using the mdc95 of the msl test may not have been appropriate .
the 
 mdc95 of a previous study was too large to usefully classify the participants 
 in our study into three groups10 . 

subjects of the previous study had high gait ability , a mean gait speed of 0.8 
 m / seconds10 , which is equivalent to 
 that of community walkers21 .
to conclude , we investigated the reliability of the msl test and the differences in step 
 distance across stepping limbs and step directions .
the test - retest reliability coefficients 
 were excellent for all step directions ( icc = 0.9390.957 ) .
in addition , paretic step distance shorter than non - paretic step 
 distance indicated good walking ability .
paretic front step distance and non - paretic front 
 step distance may be useful for discriminating independent walkers .
 [ purpose ] the purpose of this study was to determine the effect of stepping limb and step 
 direction on step distance and the association of step distance and stepping laterality in 
 step difference with walking ability and motor dysfunction . 
 [ subjects and methods ] the 
 subjects were thirty - nine patients with chronic hemiparesis as a result of stroke , who 
 performed the msl ( maximum step length ) test along with tests of motor impairment , gait 
 speed and functional ambulation category . 
 the msl test is a clinical test of stepping 
 distance in which participants step to the front , side , and back . 
 the subjects were 
 classified into three groups according to the stepping laterality in front step distance . 
 
 [ results ] step distance did not differ across stepping limbs but did differ across step 
 directions . 
 front step distance was significantly longer than side and back step distance . 
 
 participants with forward paretic step length shorter than forward non - paretic step length 
 had significantly higher walking ability than participants with symmetric forward step 
 length or forward paretic step length longer than forward non - paretic step length 
 [ conclusion ] patients with stroke have characteristic step distances in each direction . 
 
 adequate weight shift toward the paretic limb when stepping with the non - paretic limb is 
 associated with walking ability . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION