R e s e a r c h A r t i c l e A n O b je c t iv e M e a s u r e o f G a it U s in g In k F o o t p r in t s A B S T R A C T : A s tu d y w a s c o n d u c te d to te s t th e u s e fu ln e s s o f s e v e n te m p o r a l d is ta n c e m e a s u r e m e n ts (m e a s u r e m e n ts o f tim e a n d d is ta n c e ) in th e a s s e s s m e n t o f fu n c t i o n a l a m b u la tio n in s tro k e p a tie n ts . T h e se m e a s u r e m e n ts w e re o b ta in e d s im p ly a n d in e x p e n s iv e ly u sin g a p a p e r w a lk w a y a n d in k fo o tp r in ts . T h e g a it o f te n h e m ip a r e tic p a tie n ts w a s in itia lly a s s e s s e d a c c o r d in g to th e M a s s a c h u s e tts F u n c tio n a l A m b u la tio n R a tin g . E a c h p a t i e n t w a s th e n in s tr u c te d to w a lk a t h is /h e r m o s t c o m fo r ta b le s p e e d a lo n g a ten m e tr e p a p e r w a lk w a y w h ile v e lo c ity a n d c a d e n c e w e re m e a su re d . In k p a d s w ere th e n a tta c h e d to th e h e e l a n d to e o f e a c h s h o e a n d th e p a tie n ts w a lk e d a g a in a lo n g th e w alkw ay. M e a s u r e m e n ts o f s te p len g th , str id e len g th , str id e le n g th : lo w e r e x tr e m ity le n g th ratio, f o o t a n g le a n d w id th o f b a se w ere re c o r d e d a n d a n a ly se d . V e lo c ity a n d c a d e n c e w e r e f o u n d to c o r r e la te w e ll w ith th e f u n c t i o n a l a m b u la tio n ra tin g . S te p le n g th w a s f o u n d to c o r r e la te w ith th e f u n c tio n a l a m b u la tio n ra tin g , b u t th e lo n g e r s te p w a s n o t a lw a y s ta k e n w ith th e a ffe c te d leg. S trid e le n g th a n d s tr id e le n g th : lo w e r e x tr e m ity le n g th ra tio c o r r e la te d w e ll w ith th e f u n c t i o n a l a m b u la tio n ra tin g . F o o t a n g le a n d w id th o f b a s e d id n o t c o r r e la te w ith fu n c t i o n b u t a ll h e m ip a r e tic p a tie n ts s h o w e d a g r e a te r f o o t a n g le w ith th e a ffe c te d leg. T h is m e th o d o f d a ta c o lle c tio n is in e x p e n s iv e a n d e a s y to u se in a n y p h y s io th e r a p y d e p a r tm e n t a lth o u g h th e d a ta a n a ly s is is tim e -c o n s u m in g . RILEY M, MCSP, M SC (WITS)' G O O D M A N M, PHD (WITS)2 FRITZ VU, M B BCH, FCP (SA), PHD (MED)3 1 Post-graduate student, University of the Witwatersrand, Johannesburg 2 Department of Physiotherapy, University of the Witwatersrand, Johannesburg 3 Department of Neurology, University of the Witwatersrand, Johannesburg INTRODUCTION Gait analysis forms an im portant part of the assessm ent of ambulatory stroke p atients throughout the w orld. The majority o f physiotherapists assess gait by observation due to the cost o f gait analysis equipm ent and the space need­ ed to store it. If well docum ented, obser­ vational analysis can give a good basis from which to judge im provem ent in the patient’s condition but objective data for research cannot be obtained in this way. As it is becom ing increasingly important to prove that physiotherapy treatm ent is effective, a study was undertaken to investigate the use o f a simple but inex­ pensive m ethod of collecting objective m easurements. CORRESPONDENCE: M Riley Physiotherapy Department South R and Hospital Private Bag x 1 Rosettenville 2130 South A frica METHOD Subjects Ten hemiparetic subjects were selected from the wards, clinics and physiotherapy department of the Johannesburg Hospital, these being the first ten patients who met the inclusion criteria. There were seven fem ale patients and three male patients. Ages ranged from 21 to 73 years (mean 48.5 years). Eight o f the patients had suffered a stroke. Seven o f these were M iddle Cerebral Artery Strokes and one was an Internal Carotid Artery occlusion with resultant blindness in the ipsilateral eye and hem iparesis, consisting mainly o f very poor proprioception, on the con­ tralateral side. Two o f the patients had hem iparesis resulting from head injury. Bilateral neurological signs were not sig­ nificant in these two patients, consisting o f only a positive Babinsky sign on the non-hemiparetic side. Six o f the patients showed an increase in muscle tone on the hem iparetic side. T hree patients showed a decrease in m uscle tone and the one patient with poor proprioception had normal m uscle tone. O ne o f the patients w ith significantly increased m uscle tone was taking Lioresal and also wore an ankle-foot orthosis and ankle supporting boots. Five o f the subjects had a right hem i­ paresis and five had a left hemiparesis. Nine o f them were right dom inant and one left dom inant. Onset o f hem iparesis ranged from 3 m onths to 2 years prior to testing (mean 10.1 months). INCLUSION CRITERIA • To u n d erstan d w hat was required during testing • The ability to walk at least ten metres three times consecutively using any type o f w alking aid (except parallel bars) and requiring assistance from no m ore than one person. DATA COLLECTION • Each patient was allowed to read (or had read to him) an explanation o f the project and was asked if he understood what was to take place and w hether he was happy to take part in the trial. • Each patient was rated according to the M assachusetts Functional Am bulation Classification (A ppendix 1). 8 SA Jo u r n a l o f P h y s io t h e r a p y 1999 V o l 55 No 2 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) • Ink pads were attached to the patients’ shoes, red on the right and blue on the left. The ink pads were attached to the same point on each shoe along a central line drawn from toe to heel. A triangular pad was attached at the toe and a square pad at the heel. The triangular pads measured 2cm at the base and 1cm in height, the square pads m ea­ sured 2cm by 2cm. Each patient was then asked to walk at his most com ­ fortable speed along a paper walkway placed over a m easured fourteen metre length o f corridor leaving ink foot­ prints from which measurements were later taken. • M easurem ents were taken over the central ten metres o f the fourteen metre walkway with the first two metres being allowed for acceleration and the last two metres for deceleration. Data from seven temporal distance measure­ m ents were collected. T he m easure­ ments started with the first heel strike over the starting line and ended with the first heel strike over the finishing line. DATA ANALYSIS Velocity or speed o f walking - was measured in m etres per second and was calculated by dividing the ten metre data collection section by the time taken in seconds to walk along it. Cadence - steps per minute - was calcu­ lated by counting the num ber o f steps taken over the ten metre data collection section, dividing by the time taken in seconds to walk along this section and then multiplying by 60 to bring this to steps per minute. Step length is the distance from the ini­ tial contact o f one foot to the initial con­ tact o f the successive step o f the opposite foot. Right step length and left step length were m easured (fig 1). Stride length is the distance from the initial contact o f one foot to the next ini­ tial contact o f the same foot. It, therefore, includes both stance and swing phases (fig 1). Stride length to lower extremity length ratio (SL:LEL) is the stride length divided by the lower extrem ity length, the lower extrem ity length being m easured from the su p erio r b o rd er o f the g reater tro ­ chanter to the foor, bisecting the lateral malleolus. Base width at heel is the width between the heel markers on each foot. M easure­ ments were taken from the centre point o f the heel squares to the edge o f the walkway and the sm aller distance was subtracted from the larger. Base width at toe was calculated in the same m anner using the apices o f the triangular pads as reference points for m easurements. Foot angle refers to the amount o f toe- out or toe-in o f each foot. RESULTS Velocity (fig 2), cadence (fig 3), step length (fig 4), stride length (fig 5), and SL:LEL (fig 6), all showed excellent correlation with functional ambulation as rated by the M assachusetts Functional Ambulation Classification, with velocity showing the greatest correlation. The Spearm ann C orrelation coeffi­ cient was used to test the strength o f the correlation. A value o f less than 0,05 was considered significant. Foot angle and base width at heel and toe did not show correlation with functional ambulation and the results are therefore not included. DISCUSSION The measurements o f velocity, cadence, step length, stride length and SL:LEL, which were all shown in this study to co rrelate w ith functional am bulation, have also been tested by Holden et al (1984, 1986) in studies with hem iparetic and m ultiple sclerosis patients, with sim ilar results. Step Length and Stride Length FIGURE 1 Velocity vs function Functional rating FIGURE 2 Cadence vs function 0) Q. Q. £ «/> 1 1 0 - 100- 9 0 - 80 70 6 0 - 50 - 4 0 - 3 0 - r=0.719 p=0.0191 T 4 Functional rating FIGURE 3 SA J o u r n a l o f P h ysio th e ra p y 1999 V o l 55 No 2 9 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) Step length versus function Functional rating FIGURE 4 1100- 1000- l/> 9 0 0 - 0) 0) 8 0 0- E = 7 0 0- 60Q- 5 0 0- 4 0 0 - Stride length versus function Right _ _ Left• • r= 0 .9 4 p=0.0001 T 4 Functional rating FIGURE 5 r= 0 .9 4 p=0.0001 “T ~ 4 n Stride length to lower extremity length (SL: LEL) versus function Functional rating FIGURE 6 Velocity, which showed the greatest correlation to functional am bulation, has been described by Wade et al (1987) as being a reliable m easurem ent and by B randstater et al (1983) as being easily understandable and easy to use. It is also inexpensive to apply, requiring only a m easured length o f corridor or road and a stop w atch. In fact velocity can be m easured in alm ost any situation, from a physiotherapy departm ent to any rural village or township in South Africa. In normal walking right and left step lengths are equal and step length is usu­ ally speed dependent with an increase in step length occurring as velocity increases. As both right and left step lengths were m easured in this study it was interesting to note that five o f the subjects took a longer step with the affected limb while the other five did so with the unaffected limb. Four o f the five right hemiparetic patients took a longer step with the unaffected limb and four o f the five left hem iparetic patients took a longer step with the affected limb. All patients except one were right dom inant. Lehm ann et al (1987) discuss the fact that some gait param eters may be changed in hem ipa­ retic patients due to slow walking speed while others may be due to faulty bio­ mechanics. Further studies with greater num bers o f patients are needed to deter­ mine whether right hem iparetic patients tend to take a longer step with the unaf­ fected limb and left hem iparetic patients w ith the affected lim b and w hether dom inance plays a part in step length after stroke. The m easurem ents o f foot angle and base width at heel and toe, which were not found to correlate with function in this study, may be found to have greater sig n ifican ce in studies w ith a larger num ber of patients. The velocity and cadence o f the pa­ tient with poor proprioception, who had normal tone and good active movement, did not correlate so well with function as the other patients. H er problem s o f poor balance on uneven surfaces made her a category 4 p atient on the functional ambulation classification but she showed a high velocity and cadence on level surfaces. She had in fact made an extre­ m ely good recovery on level surfaces having initially been unable to walk at all due to the proprioceptive loss. The data collection method, using ink pads, presented certain initial difficulties. 10 SA Jo u r n a l o f Ph y s io t h e r a p y 1999 V o l 55 No 2 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) M oleskin, which has been used in other studies (Holden et al, 1984; 1986), was found to be insufficiently absorbent of the ink to provide clear footprints over the whole walkway. This problem was overcom e by using orthopaedic felt dipped into the ink and then stuck onto the patients’ shoes. The initial step or two were rather messy due to excess ink but this occurred in the two metre acceleration area and the footprints were clear as the patient stepped onto the m easurem ent area and rem ained so to the end o f the walkway. The data analysis was extremely time- consum ing for each patient, as lines have to be drawn and m easurements taken for each step along the ten metre walkway. It is how ever possible that a section o f two strides in the centre of the walkway could give sufficiently reliable m easurements to represent the whole walkway thus reducing analysis time. CONCLUSION The collection o f objective m easure­ ments o f gait using the ink footprint method is inexpensive and easy to use in any physiotherapy department. The data analysis is, however, time-consuming. T he m easurem ents o f velocity, cadence, step length, stride length and SL :L E L all co rrelate well w ith the M assachusetts Functional Am bulation Classification. Velocity, which is the most significant m easurem ent and also the easiest m ea­ surem ent to obtain should be recorded in all gait assessments. □ REFERENCES B ra n d stater M E, De B ruin H, G o w la n d C e t al. H em ip le g ic gait: a n aly sis o f tem poral v a ria b le s . A rc h P h y s M ed R e h a b 1983; 6 4:5 8 3 -5 8 7 . H olden M K , G ill K M , M agliozzi M R e t al. C linical g ait a sse ssm e n t in the neurologically im p a ire d : re lia b ility and m e a n in g fu ln e ss: P hys T h er 1984; 64:35-40. H o lden M K , G ill KM , M agliozzi M R. G ait a s s e s s m e n t fo r n e u ro lo g ic a lly im p a ired patients: stan d ard s fo r outcom e assessm ent: P hys T h er 1986; 55:1530-1539. L ehm ann JF, C on d o n SM , Price R, de L ateur BJ. G ait A b n o rm a litie s in H em iplegia: their correction by a nkle-foot orthosis. A rch P hys M e d R ehab 1987: 68:763-771. W ade DT, W ood VA, H eller A, M ag g s J, H ew er RL. W alking after stroke. M e a su re ­ m ent and recovery o ver the first 3 m onths. S c a n d J n l o f R eh a b M ed 1987; 19:25-30. APPENDIX 1 MASSACHUSETTS FUNCTIONAL AMBULATION CLASSIFICATION CATEGORY DEFINITION 0. Nonfunctional Ambulation Patient cannot ambulate, ambulates in bars only, or requires supervision or physical assistance from more than one person to ambulate safely outside of parallel bars. 1. Ambulator - Dependent for Physical Assistance - Level II Patient requires manual contact of no more than one person during ambulation on level surfaces to prevent falling. Manual contacts are continuous and necessary to support body weight as well as maintain balance a n d /o r assist co-ordination. 2. Ambulator - Dependent for Physical Assistance - Level 1 Patient requires manual contact of no more than one person during ambulation on level surfaces to prevent falling. Manual contact consists of continuous or intermittent light touch to assist balance or coordination. 3. Ambulator - Dependent for Supervision Patient can physically ambulate on level surfaces without manual contact of another person but for safety requires standby guarding of no more than one person because of poor judgement, questionable cardiac status, or the need for verbal cuing to complete the task. 4. Ambulator - Independent Level Surfaces only Patient can ambulate independently on level surfaces but requires supervision or physical assistance to negotiate any of the following: Stairs, inclines, or nonlevel surfaces. 5. Ambulator - Independent Patient can ambulate independently on non-level surfaces, stairs and inclines. SA Jo u r n a l o f P h y s io t h e r a p y 1999 V o l 55 No 2 11 R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. )