normal flexibility of the ankle joint is necessary for functional activities such as 
 gait1 .
limited ankle joint dorsiflexion 
 range of motion ( rom ) can cause altered foot position and compensatory movement leading to 
 musculoskeletal pain and lower extremity overuse injuries , as well as an abnormal gait 
 pattern2 . for normal
walking , adequate 
 dorsiflexion rom is necessary to contribute to the distribution of the body weight during 
 the stance phase of walking3 .
adequate 
 dorsiflexion motion at the talocrural joint is necessary for normal functional activities of 
 ankle joint , such as walking , running , jumping and many other weight - bearing activities .
a 
 minimum of 10 of dorsiflexion is required for walking , and 30 is needed for running4 .
jordan et al.5 reported that the ankle joint dorsiflexes 4 to 10 beyond neutral 
 during the stance phase of walking , and maximal dorsiflexion occurs just before heel - off . 

limited ankle 
 dorsiflexion rom during knee extension could result in compensatory changes during walking , 
 such as earlier time to heel off , increased pronation , and midtarsal joint dorsiflexion6 .
a previous study showed that participants 
 with limited ankle dorsiflexion rom showed earlier heel - off than individuals with normal 
 ankle dorsiflexion7 .
early heel - off may 
 increase the time of weight - bearing on the forefoot during the stance phase of gait , 
 resulting in ankle and forefoot injuries8 . 

repetitive abnormal loading on the forefoot may cause various injuries , such as plantar 
 fasciitis , achilles tendinitis , and ankle sprain .
insufficient length of the gastrocnemius muscle , soleus muscle , and the achilles tendon and 
 abnormal joint structures of the talocrural joint contribute to limited ankle dorsiflexion 
 rom4 .
tightness of the calf muscles 
 could impede the progression of the tibia on the talus , which favors the occurrence of an 
 excessive compensatory pronation of the subtarlar joint during gait9 , 10 .
various 
 techniques have been used for increasing ankle dorsiflexion rom to prevent biomechanical 
 change during gait and overuse injuries in rehabilitation and sports .
ankle dorsiflexion rom 
 can be increased via a variety of training and clinical techniques such as muscle 
 stretching , mobilization with movement ( mwm ) , and talus - stabilizing taping ( tst ) . a new ankle stretching orthosis ( aso )
the aso is a modification of the university of california berkley laboratory ( ucbl ) 
 foot orthosis and strap .
the talus 
 strap can be applied to the talus in the anterior to posterior with superior to inferior 
 direction in a diagonal manner4 .
the talus 
 strap can also be used to help provide stability to the talus by pulling the strap placed on 
 the talus during closed chain activities requiring tibial advancement on the foot4 .
the purpose of this study was to evaluate the effectiveness of the aso at increasing the 
 dorsiflexion rom of individuals with limited dorsiflexion rom .
we hypothesized that passive 
 and active ankle dorsiflexion rom , lunge angle , maximum dorsiflexion rom before heel - off , 
 and time to heel - off during the stance phase of the gait would increase after treadmill 
 walking with the aso .
two 
 examiners measured ankle dorsiflexion ( df ) rom . active dfrom and passive dfrom at 0 and 90 
 knee flexion
the first examiner stabilized the pelvis and lower extremities 
 to avoid compensation by other joints while active dfrom was measured . for passive dfrom 
 measurements , a hand - held dynamometer ( jtech medical , salt lake city , ut , usa )
the hand - held 
 dynamometer was placed at a point on the forefoot plantar surface 8  cm from the lateral 
 malleolus while a constant moment of force ( torque ) was applied .
torque , which was monitored 
 by the hand - held dynamometer , was applied at 111 n of force perpendicular to the plantar 
 surface of the forefoot11 .
the second 
 examiner checked the neutral position and measured the angle of the subtalar joint during 
 all ankle dfrom measurements .
the axis of the goniometer were located at the lateral 
 malleolus while the stationary arm and moving arm were place at the fibular head and 
 parallel to the lateral side of the central fifth metatarsal bone during the measurements . 
 for measuring dorsiflexion rom , a 14-inch stainless steel goniometer ( jamar , jackson , mi , 
 usa ) was used .
a 
 five - minute rest was given after every measurement to minimize learning and carry over 
 effects .
all ankle dfrom measurements were performed three times , and the goniometer was 
 repositioned every time .
an inclinometer was positioned at a point 15  cm below the center of 
 tibial tuberosity ( baseline inclinometer , irvington , new york ) .
a line was drawn on the 
 ground to keep the alignment between the heel and second toe of the subject during 
 lunge12 . a vicon motion analysis system with eight vicon mx - t10 cameras ( vicon motion systems ltd . , 

nineteen markers ( with a 
 diameter of 10 mm ) were attached to the major body parts using helen hayes marker set13 . during the static trial
, reflective 
 markers were bilaterally attached to the anterior superior iliac spine , anterior midthigh , 
 anterior midshank , lateral femoral epicondyle , medial femoral epicondyle , lateral malleolus , 
 medial malleoulus , second metatarsal head , and calcaneus .
for the dynamic trial , the medial 
 femoral epicondyle and medial malleoulus markers were removed before the participants walked 
 on a walkway in bare feet at a comfortable speed selected by themselves in the motion 
 analysis laboratory .
a total of five trials were performed and the average of three of them 
 was used in the analysis .
maximum ankle df before heel - off and time to heel - off the stance 
 phase were calculated using nexus software , version 1.7 ( vicon motion systems ltd . ,
the duration between heel - strike and toe - off was expressed as a 
 percentage of the duration of the stance phase2 , 14 .
the aso was 
 attached while subjects sat on a chair with their knees flexed 90 degrees .
the talus strap 
 and midfoot strap were pulled and fastened in pain - free positions .
the heel counterpart of 
 the orthosis was cut to decrease friction on the heel area during walking .
a soft pad was placed over the posterior 
 lateral part of the aso to decrease skin friction with the orthosis .
the medial and lateral 
 walls of the aso were cut away about 2.5  cm below the medial and lateral malleolus to 
 prevent friction at the malleolus .
the forefoot bottom of the aso was cut away at the 
 metatarsal head to allow for a natural rollover motion at the metatarsophalangeal joint when 
 walking . after attaching the aso orthosis to the foot tightly , and running shoes , 15 minutes 
 of treadmill walking
after fifteen 
 minutes of walking on the treadmill with the aso , all the variables were measured again 
 after a 10-minute rest . to assess the statistical significance of changes in each parameter after walking with the 
 aso , the paired t - test was used . a p value
< 0.05 was considered to indicate statistical 
 significance . the statistical package for the social sciences for windows version 18.0 
 ( spss , inc . ,
the changes in active and passive dorsiflexion rom , and the tibia angle during lunge after 
 treadmill walking with aso are shown in table 
 1table 1.comparison of the ankle dorsiflexion rom before and after wearing the orthosis 
 ( units : )variablesmean  sd ( )mean difference ( 95% ci)before orthosisafter orthosisdf prom with knee flexion 06.04 3.4613.773.317.73 * ( 8.21 to 6.64)df prom with knee flexion 9020.054.3127.925.347.87 * ( 9.53 to 6.20)df arom with knee flexion 08.325.7913.874.255.54 * ( 6.79 to 4.30)df arom with knee flexion 9018.256.5623.957.085.70 * ( 7.44 to 3.96)lunge angle42.034.1846.434.714.41 * ( 5.82 to 2.99 ) * , p<0.05 ( paired t - test ) .
df : dorsiflexion ; prom : passive range of motion ; arom : 
 active range of motion ; ci : confidence interval .
both active and passive dorsiflexion roms significantly increased after 
 treadmill walking with the aso ( p<0.05 ) .
df : dorsiflexion ; prom : passive range of motion ; arom : 
 active range of motion ; ci : confidence interval the degree of maximal ankle dorsiflexion before heel - off demonstrated a statistically 
 significant increase ( table 2table 2.comparison of the ankle dorsiflexion rom before heel - off and time to heel - off 
 during the stance phase of gait before and after wearing the orthosisvariablesmean  sd ( )mean difference ( 95% ci)before orthosisafter orthosismaximal ankle df rom before heel - off ( )7.96  4.5613.00  5.655.04 * ( 6.73 to 3.35)time to heel - off ( % ) 33.22  4.2635.72  4.112.50 * ( 3.31 to 1.68 ) * , p<0.05 ( paired t - test ) .
df : dorsiflexion ; rom : range of motion ; ci : confidence 
 interval ) ( p<0.05 ) .
the time to heel - off during the stance phase of the gait also 
 significantly increased after treadmill walking with the aso ( table 2 ) ( p<0.05 ) .
limited ankle dorsiflexion rom may increase stress at the plantar site and is associated 
 with lower extremity overuse injuries due to subtarlar joint pronation and early heel - off in 
 compensatory foot motion during gait . because of the importance of ankle dorsiflexion rom , 
 many clinicians make great efforts to find an intervention which increases ankle 
 dorsiflexion rom .
this study investigated the effects of treadmill walking with an aso on 
 ankle flexibility and gait pattern by measuring passive and active ankle dorsiflexion rom , 
 the angle of maximal dorsiflexion rom , and time to heel - off during gait of individuals with 
 limited ankle dorsiflexion .
treadmill walking with the aso increased passive and active dorsiflexion rom of the 
 participants .
there were also changes in the angle of maximal ankle dorsiflexion and time to 
 heel - off during the stance phase of gait .
these findings suggest that treadmill walking with 
 the aso improves ankle flexibility and normalizes the gait pattern .
loss of rom , 
 particularly dorsiflexion , results in significant gait dysfunction and overuse injury .
pope 
 et al.15 demonstrated that decreased 
 dorsiflexion rom is associated with pain and an increased risk of ankle injury .
one of the 
 most common methods of treatment for limited ankle dorsiflexion is the use of external 
 support , such as bracing and taping . external ankle support using taping or
a brace is 
 effective in rehabilitation and at preventing ankle injuries , such as sprain16 , 17 .
the present results show that treadmill walking with the aso 
 increased passive , active , and weight - bearing dorsiflexion rom .
these results are in 
 agreement with the study by yoon et al.18 , who found that 5 minutes walking with talus gliding taping increased 
 ankle dorsiflexion rom .
in addition to this , kang et al.19 reported that walking with talus taping significantly increased the 
 ankle dorsiflexion rom of individuals with limited ankle dorsiflexion .
ankle taping applied from the anterior - superior to the 
 posterior - inferior direction can assist the functional activities , such as walking and 
 lunge , of subjects with limited dorsiflexion rom19 .
however , the mwm and tst techniques have limitations , because only 
 a therapist in the physical therapy room can perform the taping , since independently 
 wrapping a taping around the talus is difficult to perform19 .
treadmill walking with the aso may elicit a similar effect on the 
 ankle joint because the talus strap applied anterior - superiorly and posterior - inferiorly 
 over the talus may help stabilize the talus during the gait .
a previous study showed that 
 passive dfrom with 0 degree knee flexion was 7.71  1.80 degree before walking with taping 
 and 11.96  2.49 degrees after walking with talus taping21 .
the results of our present study show that passive dfrom with 0 
 degree knee flexion was 6.04  3.46 before orthosis , and 13.77  3.31 after orthosis ( the 
 effect size was 2.28 ) .
these results suggest that treadmill walking with an aso may mimic 
 the manual mobilization of the mwm and tst techniques .
our results also show that treadmill walking with the aso increased maximum ankle 
 dorsiflexion before heel - off and time to heel - off during the stance phase of gait .
previous 
 studies have shown that decreased ankle dorsiflexion result in early heel - off7 , subtarlar joint pronation , and midtarsal 
 joint dorsiflexion6 during gait . early 
 heel - off
may increase weight - bearing on the forefoot during the stance phase of gait . 
 furthermore , increased loading of the forefoot is a cause of lower - extremity overuse 
 injury8 .
previous studies have reported 
 that tst increases ankle dorsiflexion before heel - off and prolongs the time to heel - off 
 during the stance phase of gait21 , and 
 that the time to heel - off significantly prolonged by 5 minutes walking with tst18 . because the time to heel - off constitutes 
 about two thirds of the stance phase during normal gait , increase of the time to heel - off is 
 regarded as an important element in the restoration of a normal gait pattern .
cornwall et 
 al.7 demonstrated that individuals with 
 restriction of dorsiflexion rom showed decreased time to heel - off , while another study 
 reported that decreased time to heel - off may result in an in the proportion of the stance 
 time increase spent weight - bearing on the forefoot22 .
we demonstrated the effect of treadmill walking with an aso on ankle dorsiflexion rom and 
 gait pattern .
treadmill walking with the aso prolonged the time to heel - off during the 
 stance phase of gait and increased active and passive dfrom , and the lunge angle .
there was 
 also an increase in the angle of maximal dorsiflexion before the stance phase .
according to 
 the results of the present study , treadmill walking with the orthosis facilitated ankle 
 flexibility and improved the kinematics of the ankle during walking via an increase in 
 dorsiflexion rom and prolongation of the time to heel - off .
the present study provides 
 evidence that treadmill walking with the aso is a beneficial intervention for improving 
 ankle flexibility and abnormal kinematics of the ankle during walking by individuals with 
 limited ankle dorsiflexion rom .
 [ purpose ] the purpose of this study was to evaluate the kinematics of the ankle in the 
 lunge to estabilish effectiveness of an ankle stretching orthosis ( aso ) on the ankle 
 dorsiflexion range of motion ( rom ) of individuals with limited dorsiflexion rom . 
 [ subjects 
 and methods ] forty ankles with decreased dorsiflexion rom of 20 participants were 
 evaluated in this study . after wearing the aso , participants walked on a treadmill for 15 
 minutes . 
 participants walked on the treadmill at a self - selected comfortable speed . 
 ankle 
 dorsiflexion rom , maximum dorsiflexion rom before heel - off , and time to heel - off during 
 the stance phase of gait were measured before and after 15 minutes of treadmill walking 
 with the aso . 
 the differences in all variables between before and after treadmill walking 
 with aso were analyzed using the paired t - test . 
 [ results ] ankle active and passive rom , 
 and dorsiflexion rom during lunge increased significantly after treadmill walking with 
 aso . 
 treadmill walking with the aso significantly increased the angle of maximal 
 dorsiflexion before heel - off and time to heel - off during the stance phase . 
 [ conclusion ] 
 the results of this study show that treadmill walking with the aso effectively improved 
 ankle flexibility and restored the normal gait pattern of the ankle joint by increasing 
 dorsiflexion rom , maximal angle of dorsiflexion , and time to heel - off in the stance 
 phase . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION