nordic walking is a physical activity consisting of walking with poles similar to ski 
 poles .
the poles are designed for 
 the purpose of activating the upper body during walking .
they are equipped with rubber or 
 spike tips , and the walking itself resembles nordic - style skiing .
beginners are asked to 
 walk in an upright position , not leaning forward or backward .
the head should be up and 
 facing forward , and the poles are held close to the body .
when the leading foot is moving 
 forward , the opposite arm swings forward to waist height .
the opposite pole strikes the 
 ground level with the heel of the leading foot .
the poles remain pointing diagonally backward and are pushed as far 
 back as possible .
the arm straightens and the hand opens , coming off the grip by the end of 
 the arm swing .
nordic walking is not expensive and can be performed throughout the year . but 
 handling of the poles is difficult , the technique required to handle them can not be easily 
 acquired by community - dwelling elderly individuals .
an intriguing phenomenon is the extent to which the human motor system can transfer 
 relevant strategies learned in one context to other similar situations .
experimental 
 paradigms using upper limb tasks show the ability of the nervous system to generalize 
 learned motor skills to similar movements , contexts , or workspaces and even to the opposite 
 limb1,2,3,4 . 

such studies have yielded valuable insights into how the nervous system codes and 
 generalizes motor skills .
walking is a motor task that is highly flexible in its adaptation 
 to different situations .
extensive work has shown the ability 
 of the locomotor system to adapt to changes in sensory input from the limbs5,6,7 .
in addition , the walking pattern is easily 
 modified to accommodate different external constraints , for example , navigating over or 
 around obstacles8 or different slopes of 
 the walking surface9 , 10 .
therefore , it is 
 important for elderly individuals to train with movements in the backward direction to 
 prevent falling forward .
nordic backward walking ( nbw ) is a very difficult form of walking 
 for beginners , and we do not currently know the effect of repetition of nbw on movement in 
 the backward direction in the elderly .
the aims of this study were : 1 ) to confirm the motor learning process of nbw in older adult 
 community - dwelling volunteers and 2 ) to check the change in psychological condition 
 resulting from nbw .
we evaluated 19 older adult 
 community - dwelling volunteers ( 11 female and 8 male ; mean age 644 ) ( table 1table 1 .
general characteristics of participants ( n=19)indexesmeansdage ( years)644gender ( male / femal)11/11functional reach test ( cm)28.17.5bone density ( g / cm)2.40.2mini - mental state examination ( point)291 ) . the volunteers ( n=19 ) were included based on the following criteria : 1 ) 
 self - report of good health and 2 ) absence of a history of psychiatric or neurological 
 disorder .
all participants gave informed consent , and the study was approved by the ethics 
 committee of kansai university of welfare sciences .
we measured nbw consecutively 
 five times and then measured it a sixth time one hour later .
no participants reported fatigue , 
 likely because of the short walking distance and limited number of trials .
the primary variables of interest were walking 
 speed , stride length , and visual analogue scale ( vas ) .
the vas was used as an index of sense 
 of fear for walking backward .
a paired t - test was used to compare the mean front and back scores . the alpha level for 
 statistical significance
all data were analyzed using the 
 statistical package for the social sciences ( spss ) version 19 .
our results demonstrated that following repeated sessions of backward walking , the walking 
 speed during nbw in the first , second , third , fourth , and fifth sessions were 73 m / min , 80 
 m / min , 86 m / min , 88 m / min , and 91 m / min , respectively .
significant differences were only 
 found between the first and second sessions and between the second and third sessions .
the 
 walking speed in the sixth session ( 86 m / min ) , measured one hour later , was decreased in 
 comparison with that in the fifth session .
the stride lengths during nbw in the first , 
 second , third , fourth , and fifth sessions were 0.52 m , 0.56 m , 0.58 m , 0.59 m , and 0.59 m , 
 respectively .
significant differences were only found between the first and second sessions 
 and between the second and third sessions .
the stride length in the sixth session ( 0.56 m ) , 
 measured one hour later , was decreased in comparison with that in the fifth session .
the vas 
 scores after nbw for the first , second , third , fourth , and fifth sessions were 4.03  cm , 
 3.46  cm , 2.95  cm , 2.47  cm , and 2.00  cm , respectively .
in addition , the vas score for the sixth 
 session ( 2.00  cm ) , measured one hour later , was increased compared with that for the fifth 
 session ( table 2table 2 .
motor learning during nordic backward walking ( n=19)1st2nd3rd4th5th6thbackward walking speed ( m / min)732180*2086*21882491288623stride length ( m)0.520.100.56*0.120.58*0.110.590.130.590.120.560.11visual analogue scale ( cm)4.032.393.46*2.352.95*2.252.47*2.392.00*2.291.662.04values are presented as the averagesd .
this study investigated the learning process in beginners learning how to perform nbw using 
 nordic poles .
our results demonstrated that following repeated sessions of backward walking , 
 the walking speed during nbw showed significant differences only between the first and 
 second sessions and between the second and third sessions .
the walking speed in the sixth 
 session , measured one hour later , was decreased in comparison with that in the fifth 
 session .
unlike the subjects studied by lake and cavanagh11 , our subjects demonstrated a clear increase in efficiency , likely 
 as a result of increased efficiency of motor unit recruitment due to practice .
the differing 
 results can most likely be explained by considering the differences in the type of exercise 
 used .
backward walking is truly a novel task , whereas even individuals who do not 
 specifically train with forward running do engage in forward walking .
therefore , the motor 
 pathways used for any forward locomotion are at least somewhat trained , whereas those used 
 for backward locomotion are untrained .
significant differences in stride length during nbw were only found between the first and 
 second sessions and between the second and third sessions .
the stride length in the sixth 
 session , measured one hour later , was decreased in comparison with that in the fifth 
 session . specifically , the increase was significant between the fourth and sixth week of 
 training .
schwane et al.12 suggested that 
 a novel activity may require increasingly greater motor unit recruitment in order to 
 complete a task .
although we did not specifically examine muscle activity , backward walking 
 requires greater sustained emg activity of the quadriceps than forward walking13 , 14 .
thus , we believe our findings are the first to demonstrate that an 
 individual may perform backward walking more efficiently after repeated sessions of backward 
 walking training .
significant differences in vas score after nbw were found for each session . in addition , 
 the stride length in the sixth session , measured one hour later , was decreased in comparison 
 with that in the fifth session .
if the energy cost decreases as a person learns a new motor 
 skill , as suggested by schwane et al.12 , 
 the prescribed exercise workload , per the regression equations reported by myatt et al.15 and clarkson et al.16 , may not have the intended training effect .
our findings 
 are consistent with the hypothesis that efficiency increases when a task is no longer 
 novel .
therefore , it is important for elderly individuals to train with backward movements to 
 prevent falling forward .
the skill of the subjects in performing nbw rose with every 
 repetition , but they learned at a slow pace .
also , their level of skill tended to decrease 
 when they took a break between sessions .
however , their sense of fear did not worsen even if 
 they took a break .
this finding suggests that nbw is indeed a novel task and that motor 
 learning occurs as a result of practice , leading to a more efficient recruitment of motor 
 units .
therefore , nbw was a form of training that matched with the preferences of the 
 elderly and was thought to be useful as a backward walking exercise for the elderly .
nbw can 
 be performed anywhere and anytime , and therefore , widespread clinical application of nbw is 
 possible .
   [ purpose ] the aims of this study were : 1 ) to confirm the motion learning process of 
 nordic backward walking ( nbw ) in older adult community - dwelling volunteers and , 2 ) to 
 check the change in psychological condition resulting from nbw . 
 this study examined 
 whether the learning process and psychological condition become more efficient after 
 repeated sessions of nbw . 
 [ methods ] the subjects were 19 community - dwelling elderly 
 individuals between the ages of 64 and 78  years . 
 [ results ] significant differences in 
 walking speed during nbw were only found between the first and second sessions and between 
 the second and third sessions . 
 the walking speed in the sixth session , measured one hour 
 after the fifth session , was decreased in comparison with that in the fifth session . 
 
 significant differences in stride length during nbw were only found between the first and 
 second sessions and between the second and third sessions . 
 the stride length in the sixth 
 session , measured one hour after the fifth session , was decreased in comparison with that 
 in the fifth session . 
 significant differences in vas score ( sense of fear ) after nbw were 
 found for each session . 
 vas score for the sixth session , measured one hour after the fifth 
 session , was decreased in comparison with that for the fifth session . 
 [ conclusions ] the 
 findings in the present study suggest that nbw is indeed a novel task and that motor 
 learning occurs as a result of practice , leading to a more efficient recruitment of motor 
 units . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION