the 8ch wireless motion recorder ( mvp - rf8 series ) is an inertial measurement unit made by 
 microstone inc .
it is an electronic device that uses the combination of an 
 accelerometer , gyroscope , and magnet attachment ( option that provides a reference frame ) to 
 record the location and orientation of the device in 3d space .
the location and orientation 
 are detected by calculating linear displacement ( using accelerometer data ) and rotational 
 displacement ( using gyroscope data ) of the device from a reference point .
the mvp - rf8 series 
 can be used to record behavior , rehabilitation and sports for motion analysis . tao zheng et 
 al .
reported use of a miniature wireless motion recorder ( mvp - rf8-gc ) to record the maximum 
 cervical range of motion ( rom ) and joint position error before and after interventions1 .
walking is an essential movement and is the most frequently performed action by human 
 beings2 .
racewalking is an olympic 
 event , and the popularity of racewalking has increased steadily .
it has not yet attracted 
 large numbers of adolescents in china , but there appear to be indications that the event is 
 growing in popularity .
racewalking events of 5 and 10  km are becoming increasingly popular 
 for amateur athletes , and successes in these relatively short events have inspired some 
 teenagers to attempt longer distance races .
a number of walking enthusiasts have attributed 
 the rising popularity of racewalking to decline in the popularity of jogging and this trend 
 has been influenced by widespread belief that racewalking is a sport providing opportunities 
 for competitions , as well as valuable health and fitness benefits , without significant risk 
 of injury3 .
previous research has shown that success in race walking is related more to the efficiency 
 of technique rather than physiological factors4 .
the kinematics of the forefoot in racewalking are triplanar 
 motions . since the axis of the subtalar joint is not in any cardinal plane , the motions 
 occurring in the subtalar joint present a triplanar motion pattern .
the triplanar motions of 
 the forefoot are as follows : transverse motion , frontal motion and sagittal motion .
the 
 transverse motions occurring primarily in the subtalar joint are composed of medial rotation 
 ( adduction ) , which is movement of the forefoot or part of the foot medially in horizontal 
 plane and lateral rotation ( abduction ) , which is movement of the forefoot or part of the 
 foot laterally in the horizontal rotation .
rotations in the coronal plane were defined as 
 inversion and eversion rotation . during running , both medial and lateral rotation
were 
 observed in the footprints of the rearfoot and forefoot in the horizontal plane5 .
there are significant differences between 
 racewalking and normal walking or jogging during the stance phase ( closed kinematic chain 
 motions ) of the gait cycle .
this is because two simple rules govern racewalking : the first 
 rule of racewalking demands that at least one foot is in contact with the ground at all 
 times .
the second rule of racewalking 
 demands a straight leg from contact with the ground until the leg reaches the vertical 
 upright position relative to the ground , which distinguishes racewalking from normal 
 walking . keeping the leg
straight with foot introversion increases torque at the knee , and 
 this may be a potential factor for lower extremity injuries .
in fact , although treadmills may not be suitable for everyone , they offer walkers many more 
 options for more efficient workouts
. one of their best features is that they can be set at 
 various paces .
racewalkers often use treadmills because of the benefits of having a flat 
 unchanging surface allowing pace judgment to be learned6 .
the purpose of this study was to investigate the changes in 
 proximal lower leg and forefoot kinematics , and reliability of measurement during different 
 paces of barefoot racewalking on treadmill .
the participants were 
 students of the huaian sports school of huaian city , china . to be included in the study , 
 each participant was required to have been trained at the school for at least 3  years .
the 
 participants characteristics are detailed in table 
 1table 1.characteristics of the subjects ( n=11)age ( years)16.31.9weight ( kg)58.410.1height ( cm)177.810.7data are presented as the mean  standard deviation .
data are presented as the mean  standard deviation the participants were excluded if they had a lower limb or foot injury , visual problems , or 
 vestibular problems .
the participants signed an informed document approved by the ethics 
 committee of jangsu province huaian sports school , which also approved the study . before the 
 testing session ,
all of the participants were supervised while they performed a 10-minute 
 conventional routine warm - up .
the participants were asked to refrain from any exercise for 2 
 hours before testing .
participants walked barefoot on an instrumented treadmill . the lower leg proximal end and 
 forefoot maximum inversion /
eversion ( i / e ) rotation and medial / lateral ( m / l ) rotation were 
 measured with an 8ch wireless motion recorder ( mvp - rf8-bc , microstone inc . ,
saku , japan ) 
 during racewalking at pace of 5 and 9  km / h .
the wireless motion recorder was attached to the 
 third and forth metatarsal of the right foot in order to record forefoot kinematics and to 
 the proximal end of the right lower leg and just below the proximal end of the fibula to 
 record lower leg proximal end kinematics .
the sampling rate of the wireless motion recorder 
 was 200  hz , and the data were transmitted by bluetooth to a computer .
the data were 
 collected for 6 seconds in two capture stages and approximately 30 seconds plateau was 
 reached in each stage .
the participants motion characteristics in 3 consecutive gait cycles 
 at each of the 2 speeds were recorded and analyzed with the mvp - rf8-bc analysis software 
 system .
a video camera 
 ( 200 fps ) was simultaneously used to record the cycle phases and racewalking technique .
differences 
 in lower leg proximal end and forefoot kinematics were compared by employing the independent 
 t - test .
the 
 intra - class correlation coefficient ( icc1 , 2 ) was also calculated to investigate the 
 within - subject reliability of proximal lower leg and forefoot kinematics .
the lower leg proximal end and forefoot maximum inversion / eversion ( i / e ) rotation and 
 medial / lateral ( m / l ) rotation during barefoot racewalking at the 5  km / h and 9  km / h paces on 
 the treadmill are shown in table 2table 2.comparison values of ll i / e , ll m / l , f i / e and f m / l at different paces 
 ( n=11)pace5 km / h9 km / hll
m / l3.60.7 4.20.6*f i / e12.32.2 11.64.1f m / l5.11.2 6.70.7**data are presented as the mean  standard deviation . significant differences at different paces : * p<0.05 ; * * p<0.01 .
ll i / e and ll m / l : lower leg proximal end maximum inversion / eversion and 
 medial / lateral rotation .
f i / e and f m / l : forefoot maximum inversion / eversion and medial / lateral rotation .. the independent t - test showed that there were significant 
 differences in the lower leg proximal end and forefoot maximum medial / lateral ( m / l ) 
 rotations at the 9  km / h pace compared with those at the 5  km / h pace . the icc values ( 1,2 ) 

are shown in table 3table 3.interexamer reliability of ll i / e , ll m / l , f i / e and f m / l at different paces 
 ( n=11)pace5 km / h   9 km / hll i / e0.820.87ll m / l0.890.93f i / e0.920.93f m / l0.840.91ll i / e and ll m / l : lower leg s proximal end maximum inversion / eversion and 
 medial / lateral rotation .
f i / e and f m / l : forefoot maximum inveesion / eversion and medial / lateral rotation .. the values of lower leg proximal end and forefoot maximum inversion / eversion 
 ( i / e ) rotation and medial / lateral ( m / l ) rotation at the 5  km / h and 9  km / h paces showed a 
 high level of reliability .
the intra - examiner reliability estimates ranged from 0.82 and 
 0.89 to 0.87 and 0.93 for lower leg proximal end inversion / eversion ( i / e ) rotation and 
 medial / lateral ( m / l ) rotation , and from 0.92 and 0.84 to 0.93 and 0.91 for forefoot 
 inversion / eversion ( i / e ) rotation and medial / lateral ( m / l ) rotation .
ll i / e and ll m / l : lower leg proximal end maximum inversion / eversion and 
 medial / lateral rotation .
f i / e and f m / l : forefoot maximum inversion / eversion and medial / lateral rotation .
ll i / e and ll m / l : lower leg s proximal end maximum inversion / eversion and 
 medial / lateral rotation .
f i / e and f m / l : forefoot maximum inveesion / eversion and medial / lateral rotation .
using a wireless motion recorder ( mvp - rf8-bc ) , the lower leg proximal end and forefoot 
 kinematics were measured during racewalking at 5  km / h and 9  km / h paces and their measurement 
 reliabilities were investigated .
there were significant differences in the lower leg 
 proximal end and forefoot maximum medial / lateral ( m / l ) rotations at the 9  km / h pace compared 
 with those at the 5  km / h pace .
this may indicate that the lower leg proximal end and 
 forefoot kinematics of barefoot racewalking on a treadmill are influenced by different paces 
 and that assessment of lower leg proximal end and forefoot kinematics by means of the 
 wireless motion recorder ( mvp - rf8-bc ) is adequately reliable .
motion capture is usually used in the medical science field for analyzing the physics of 
 human motion , especially in biomechanics studies related to sports and rehabilitation .
study the 
 wireless motion recorder ( mvp - rf8-bc ) was used to record the parameters of the moving body s 
 trajectory .
 [ purpose ] this study was performed to investigate the changes in lower leg proximal end 
 and forefoot kinematics , and reliability of measurement during different paces of barefoot 
 racewalking on treadmill . 
 [ subjects ] eleven junior racewalking men participated in this 
 study . [ methods ] to identify changes in lower leg proximal end and forefoot kinematics , 
 during different paces of barefoot racewalking on a treadmill , a wireless motion recorder 
 ( mvp - rf8-bc ) was used . 
 interclass correlation coefficients ( icc 1 , 2 ) were used to 
 estimate reliability . 
 [ results ] there were significant differences in the lower leg 
 proximal end and forefoot maximum medial / lateral rotations at a pace of 9  km / h compared 
 with those at a pace of 5  km / h pace . 
 the intra - examiner reliability estimates ranged from 
 0.82 and 0.89 to 0.87 and 0.93 for lower leg proximal end inversion / eversion rotation and 
 medial / lateral rotation , and from 0.92 and 0.84 to 0.93 and 0.91 for forefoot 
 inversion / eversion rotation and medial / lateral rotation . 
 [ conclusion ] we conclude that the 
 lower leg proximal end and forefoot kinematics of barefoot racewalking on a treadmill are 
 influenced by different paces and that assessment of lower leg proximal end and forefoot 
 kinematics by means of the wireless motion recorder ( mvp - rf8-bc ) is adequately reliable . 
 
 this information may be useful for determining exercise prescriptions . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION