underwater treadmill training is a method of gait training that uses the characteristics of 
 water .
water provides buoyancy , hydrostatic pressure , and viscosity , affecting the human 
 body1 .
water depth supports body weight : water as high as symphysis pubis relieves the 
 weight by 40% , as high as the navel relieves by 50% , and as high as the xiphoid process 
 relieves more than 60% of the weight1 .
the 
 water pressure rises as immersion depth increases , and the increase in water pressure 
 induces movement of bodily fluids .
due to the viscosity of water , friction occurs against 
 the skin , and fluid resistance of the water enables it to be used in resistance 
 training1 .
underwater treadmill gait training utilizes water buoyancy to run a gait training session 
 with alleviated weight .
the training method is similar to the on - ground weight support 
 treadmill gait training2 , 3 .
underwater treadmill training itself is a complete 
 work - out , by which subjects can practice walking ; therefore , it is one of the gait training 
 methods that can be normally used2 , 3 .
most studies of gait training were of 
 on - ground techniques and few studies have focused on underwater treadmill training . 
 considering this background ,
our working hypothesis is that underwater treadmill training 
 improves the normal people s gait ability .
the selection criteria were as follows : 
 no history of orthopedic surgery on a lower limb , never taken any drug due to a neurologic 
 problem , and no musculoskeletal system disease .
their average age was 21.20  2.30  years 
 old , height was 174.51  9.62  cm , and weight was 73.85  7.27  kg .
sufficient explanation of 
 this study s intent and the overall purpose was given , and voluntary consent to 
 participation in this study was obtained from all of the subjects .
information on the study 
 and written informed consent according to the ethical standards of the declaration of 
 helsinki were provided to all subjects prior to their participation .
gait training is performed using the underwater treadmill ( hydrotrack 
 underwater treadmill system , conray , inc . , phoenix , az , usa ) , for twenty minutes per 
 session , five sessions a week for four weeks .
the water temperature was set at about 33  c 
 and the depth was fixed to reach between the subjects xiphoid process and the navel .
round 
 1 is composed of five minutes walking on the underwater treadmill at a comfortable speed . on 
 round 2 , the speed was slowly increased by 0.5  km / h every two minutes , then when the rating 
 of perceived exertion ( rpe ) reaches the score of 13 ( somewhat hard ) after the start , that 
 level of rpe was maintained for ten minutes . if a subject s rpe is not maintained at the 
 high speed , the previous speed was used instead .
finally , during round 3 , the exercise was 
 completed with five minutes at the comfortable speed4 .
the gaitrite is a portable gait anlaysis tool for automated measurement of spatio - temporal 
 gait parameters . to precisely analyze gait , the subjects were asked to walk along a two 
 meter long walkway for three sessions , and the average values were used .
the subjects , with 
 heads lifted and looking straight ahead , walked barefoot while lightly shaking their upper 
 arms5 .
the gaitrite system has excellent 
 reliability for most spatio - temporal gait parameters in both young ( icc=0.880.92 ) and older 
 subjects ( icc=0.880.91)6 the mean and sd were calculated for each variable . before the intervention
, differences in 
 the general characteristics of the experimental group were analyzed by descriptive 
 statistics .
variables were compared before and after training within experimental group 
 using paired sample t - tests .
the statistical analysis was conducted using spss 20.0 ( spss , chicago , il , usa ) , and 
 statistical significance was accepted for p values < 0.05 .
after the intervention , step length , velocity , and cadence increased significantly 
 ( p<0.05 ) ( table 1table 1.comparison of changes in characteristics of the experimental group ( n=20)pre - testpost - teststep length ( cm)54.17 ( 5.25)57.81 ( 6.54)*velocity ( m / s)86.24 ( 3.54)92.74 ( 4.51)*double support ( % ) 17.24 ( 12.67)21.58 ( 6.81)cadence ( steps / min)102.74 ( 15.42)109.62 ( 13.91)mean  sd , significant difference from the pre - intervention 
 value , * p<0.05 ) . mean  sd , significant difference from the pre - intervention 
 value , * p<0.05
this study conducted underwater treadmill training with normal people , yielding a positive 
 effect on gait ability .
light aerobic exercise , walking , running , side steps to music in 
 chest - deep water for three thirty - minute sessions a week for eight weeks , enhances maximum 
 oxygen consumption by 22% , and improves walking speed , walking distance and muscular 
 strength7 .
masumoto et al.8 observed an increase in walking speed due to 
 strengthened hip flexor muscles , and an increase in cadence from increased step length in 
 the elderly after underwater treadmill training .
underwater treadmill training s use of 
 buoyancy eases partial support of weight and its stable applicability provides psychological 
 stability ; these two factors seem to induce increased step length , velocity , and 
 cadence8 .
the underwater treadmill 
 training session is a method in which patients repeatedly walk a certain length within a 
 fixed time at a constant rate under a limited depth of water .
this provides double support 
 and improve gait and balancing abilities as it provides stability during the stance period 
 of walking9 .
the limitations of this study were a small sample size , lack of a follow - up test to 
 determine the carry - over effects , and no constraint of the effects of other joints .
further 
 investigation of the effects of an underwater treadmill training in subjects with 
 modifications to address the above - mentioned limitations is needed .
 [ purpose ] our working hypothesis is that underwater treadmill training improves normal 
 people s gait ability . 
 [ subjects and methods ] twenty - five healthy subjects with no 
 orthopedic history of lower extremity were recruited . 
 gait training is performed using an 
 underwater treadmill ( hydrotrack underwater treadmill system , conray , inc . , 
 phoenix , az , usa ) , for twenty minutes per session , five sessions a week for four weeks . 
 
 the water temperature was set at about 33  c and the depth was fixed to reach between the 
 subjects xiphoid process and the navel . 
 [ results ] after the intervention , step length , 
 velocity , and cadence increased significantly . [ 
 conclusion ] this study conducted 
 underwater treadmill training with normal people , with positive effects on gait 
 ability . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION