***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: INTRODUCTION The limitations of clinical methods for appraising foot posture are well documented . A new measure , the Foot Posture Index is proposed , and its development and validation described . METHODS A four-phase development process was used : ( i ) to derive a series of c and i date measures , ( ii ) to define an appropriate scoring system , ( iii ) to evaluate the validity of components and modify the instrument as appropriate , and ( iv ) to investigate the predictive validity of the finalised instrument relative to static and dynamic kinematic models . Methods included initial concurrent validation using Rose 's Valgus Index , determination of inter-item reliability , factor analysis , and benchmarking against three dimensional kinematic models derived from electromagnetic motion tracking of the lower limb . RESULTS Thirty-six c and i date components were reduced to six in the final instrument . The draft version of the instrument predicted 59 % of the variance in concurrent Valgus Index scores and demonstrated good inter item reliability ( Cronbach 's alpha = 0.83 ) . The relevant variables from the motion tracking lower limb model predicted 58 - 80 % of the variance in the six components retained in the final instrument . The finalised instrument predicted 64 % of the variance in static st and ing posture , and 41 % of the variance in midstance posture during normal walking . CONCLUSION The Foot Posture Index has been subjected to thorough evaluation in the course of its development and a final version is proposed comprising six component measures that performed satisfactorily during the validation process . The Foot Posture Index assessment is quick and simple to perform and allows a multiple segment , multiple plane evaluation that offers some advantages over existing clinical measures of foot posture Previous methods of measuring footprints for the purpose of classifying foot type are review ed . A planimetric method is presented for characterizing footprints using the ratio of the area of the middle third of the footprint to the entire footprint area ( excluding the toes ) . This ' arch index ' during 50 % body weight st and ing provides an objective measure for comparative purpose s with a measured reliability , within day and between day , of 0.96 and 0.94 respectively . Values measured from footprints taken during other activities show variable responses in different subjects . Examples of the arch index taken from static footprints of various feet are presented and data are reported from 107 r and omly selected subjects during half body weight stance . Criteria are suggested for the classification of footprints as high , normal , and flat arch Objective : Although boys are frequently reported to have flatter feet than girls , there has been little systematic research to confirm or explain this structural difference between the genders . The objective of this study was to determine whether flat-footedness was moderated by gender in Australian preschool children and , if so , to determine the cause of this between-gender difference in structure of the plantar surface of the foot . Methods :  Foot anthropometry , Arch Index derived from plantar footprints , and midfoot plantar fat pad thickness measured by ultrasound  were obtained for the left and right feet of 52 girls and 36 boys ( mean age , 4.2 ± 0.6 years ) . The children were recruited from 10 r and omly selected preschools from the Illawarra region of New South Wales , Australia . Results : In agreement with previous research , the preschool boys displayed significantly flatter feet than the girls ( P ≤ 0.04 ) . Although there were no between-gender differences in structural foot dimensions , the boys had a significantly thicker midfoot fat pad than the girls by approximately 0.4 and 0.5 mm on both the right and left feet , respectively . Conclusions : The increased incidence of flat-footedness in boys compared with girls of the same age seems to be caused by a thicker plantar fat pad in the medial midfoot in boys . This suggests that the development of the medial longitudinal arch may be progressing at a slower rate in boys than in girls , and that intervention for a flexible flat foot , particularly for young boys , may be unnecessary Developmental Coordination Disorder ( DCD ) is a neurodevelopmental disorder characterised by impaired motor co-ordination and awkward gait . Despite self-reported findings of pes planus and joint hypermobility in children with DCD , there is little objective evidence regarding the clinical management of the foot in children with DCD . The aims of this research were to report clinical findings of foot posture and lower limb hypermobility in children with DCD and to evaluate the impact of foot orthoses on spatio-temporal gait parameters . Children with DCD were recruited into the study . Participants were r and omly assigned to an intervention group who received foot orthoses at the start of their rehabilitation programme or to a second group who received foot orthoses at the end of their intervention programme . Foot posture was assessed with the Foot Posture Index and lower limb hypermobility assessed with the Lower Limb Assessment Score . The effect of foot orthoses  was evaluated through assessment of spatio-temporal gait characteristics at baseline and post-rehabilitation programme . Fourteen children were recruited ( mdn age 7.5 years ) with nine children assigned to the group receiving orthoses early ( mdn age 8 years ) and five children assigned to the post-rehabilitation orthoses group ( mdn age 6.5 years ) . A pes planus foot posture ( FPI score=8 ) and lower limb hypermobility ( LLAS score=11 ) were observed . Changes in spatio-temporal gait parameters failed to reach significance ( p>.012 ) following orthotic invention but demonstrated a trend towards a decreased cadence and increased double support duration . Despite non-significant findings this work offers preliminary support for podiatric intervention in the rehabilitation of children with DCD . Further work is required to underst and the biomechanics of gait in children with DCD and appreciate the role of podiatry as a component of multidisciplinary care BACKGROUND Flatfoot , or pes planus , is one of the most common foot posture problems in children that may lead to lower-extremity pain owing to a potential increase in plantar pressure . First , we compared plantar pressure distribution between children with and without flatfoot . Second , we examined the reliability and accuracy of a simple metric for characterization of foot posture : the Clarke angle . Third , we proposed a mathematical model to predict plantar pressure magnitude under the medial arch using body mass and the Clarke angle . METHODS Sixty children with flatfoot and 33 aged-matched controls were recruited . Measurements included in-shoe plantar pressure distribution , ground reaction force , Clarke angle , and radiography assessment .  The measured Clarke angle was compared with radiographic measurements , and its test-retest reliability was determined . A mathematical model was fitted to predict plantar pressure distribution under the medial arch using easy-to-measure variables ( body mass and the Clarke angle ) . RESULTS A high correlation was observed between the  Clarke angle  and  radiography measurements ( r > 0.9 ; P < 10(-6 ) ) . Excellent between- and within-day test-retest reliability for Clarke angle measurement ( intraclass correlation coefficient , > 0.9 ) was observed . Results also suggest that pressure magnitude under the medial arch can be estimated using the Clarke angle and body mass ( R(2 ) = 0.95 ; error , < 0.04 N/cm(2 ) [ 2 % ] ) . CONCLUSIONS This study suggests that the Clarke angle is a practical , reliable , and sensitive metric for quantification of medial arch height in children and could be recommended for research and clinical applications . It can also be used to estimate plantar pressure under the medial arch , which , in turn , may assist in the timely intervention and prognosis of prospect i ve problems associated with flatfoot posture Both feet of two hundred and seventy two children aged between five years six months and ten years and eleven months were studied using a footprint technique called the arch index ( Al ) , and the vertical height of the navicular ( NH ) as non invasive techniques of objective measures of the medial longitudinal arch ( MLA ) . In addition to age the study investigated the influence of gender , limb dominance , and body weight . The study found the existence of a relationship between the two measures of the MLA . There was no significant difference in NH measures between males and females and body weight did not affect the NH . The NH changed with age , suggesting it provides a useful , easily obtained clinical measure . The Al measures were slightly more reliable than the NH but showed less change with age Flat feet in children are common , and at times symptomatic , but the relationship between function and symptoms or impairment is still unclear . We undertook a prospect i ve , observational study comparing children with paediatric flexible flat foot ( PFF ) and children with neutral feet ( NF ) using three dimensional gait analysis ( 3DGA ) . It was hypothesised that children with PFF would demonstrate differences in both spatio-temporal parameters of gait and foot and ankle kinematics compared to the NF group and that these differences would correlate with impaired quality of life ( QoL ) . The kinematic differences were expected to be most marked in hindfoot coronal plane motion and forefoot sagittal and transverse plane motion . Eighty-three children between the ages of 8 and 15 were recruited in this study : Forty-two were classified as having PFF and forty-one as NF . Each child underwent 3DGA and completed the  Oxford Ankle Foot Question naire for Children ( OxAFQ_C ) . Reduced OxAFQ_C physical domain scores in the PFF children were associated with slower walking speed ( p=0.014 ) and reduced normalised stride length ( p=0.008 ) . PFF children also demonstrated significantly increased hindfoot eversion and forefoot supination during gait . Significant differences between groups were not observed for other foot and ankle joint motions . Increased maximum hindfoot eversion and increased forefoot supination correlated strongly with lower QoL scores in PFF children . These data further our underst and ing of the functional characteristics that lead to impaired QoL in PFF children . These findings will help guide the surveillance and management of children with this ubiquitous condition Childhood obesity exerts abnormally high stresses on developing foot structures which can lead to structural deformity of the foot . Screening for foot problems in children with overweight helps detect interior risks restricting normal lifestyle in these individuals . The purpose of this study was to investigate the effects of excess weight on the structure and function of the developing foot in students aged 7–14 years . A total of 667 participants were recruited for this cross‐sectional study via a multi‐level cluster sampling method ( r and omization was used within each cluster ) . All subjects ( 340 boys and 327 girls ) attended primary and secondary schools in Isfahan City , Iran . The children 's feet were evaluated using clinical assessment s and footprint‐based measures whilst fully weight bearing . Significant differences were observed in the frequency of flatfoot between normal weight , overweight and obese groups ( P < 0.001 ) ; participants who were more overweight had flatter feet . Children with higher weight also had a more pronated heel , less dorsiflexion range and higher reported pain within physical activity . This study indicated that childhood obesity is associated with structural foot and ankle deformities and activity‐related foot pain In making treatment decisions , doctors and patients must take into account relevant r and omised controlled trials ( RCTs ) and systematic review s. Relevance depends on external validity ( or generalisability)--ie , whether the results can be reasonably applied to a definable group of patients in a particular clinical setting in routine practice . There is concern among clinicians that external validity is often poor , particularly for some pharmaceutical industry trials , a perception that has led to underuse of treatments that are effective . Yet research ers , funding agencies , ethics committees , the pharmaceutical industry , medical journals , and governmental regulators alike all neglect external validity , leaving clinicians to make judgments . However , reporting of the determinants of external validity in trial publications and systematic review s is usually inadequate . This review discusses those determinants , presents a checklist for clinicians , and makes recommendations for greater consideration of external validity in the design and reporting of RCTs BACKGROUND The purpose s of this study were 1 ) to determine the intrarater and interrater reliability of the arch height index measurement system device , 2 ) to establish population normative values for the arch height index in recreational runners , and 3 ) to compare arch height index values between the right and left feet and between genders . METHODS Eleven subjects were used to establish intrarater and interrater reliability of the arch height index measurement system . This system was then used to measure the arch height index of 100 recreational runners . RESULTS Measurements taken with the arch height index measurement system device exhibited high intrarater and interrater reliability . The mean + /- SD arch height index of the recreational runners was 0.340 + /- 0.030 . Men had larger feet than women , but the arch height index between genders was similar . CONCLUSIONS The arch height index measurement system device is reliable to use between testers while simplifying the measurement procedure for recording the arch height index . The arch height index may be helpful in identifying potential structural factors that predispose individuals to lower-extremity injuries OBJECTIVE . To analyse the association between overweight and obesity and foot structure in children older than 9 years of age , whose longitudinal medial arch ( MLA ) should be practically established . DESIGN , SETTING AND SUBJECT . A cross-sectional study of 245 children ( age : 13.22±1.8 years ) from four r and omly selected schools ( Zaragoza , Spain ) .  Body mass index ( BMI ) was calculated and normal-weight , overweight and obese groups were defined . Footprints for both feet were collected . MEASUREMENTS . Foot angle ( FA ) and Chippaux-Smirak index ( CSI )  were calculated from the footprints . Height and body mass were measured to calculate the BMI . RESULTS . Mean values of FA and CSI in the normal-weight group indicated the presence of a normal MLA ; however , in the overweight they indicated an intermediary MLA and in the obese group , a low MLA . Comparison among the groups showed a decrease of FA ( p<0.01 ) and an increase of CSI ( p<0.01 ) with increasing weight associated with a lower MLA . A low but significant correlation ( p<0.0001 ) was found between the z-score BMI and footprint parameters . CONCLUSIONS . In children aged 9 to 16.5 years , the increase of 
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Conclusion No universally accepted criteria for diagnosing paediatric flat foot was found within existing literature , and psychometric data for foot posture measures and definitions used was limited .