Limited evidence to strong evidence was found for reliability in various chronic conditions .
Little evidence was available for responsiveness and measurement error .
Studies showed large variability in test procedures despite existing guidelines for the performance of the 6MWT .
Evidence for measurement properties of the 6MWT  varies largely among chronic pediatric conditions .
BACKGROUND The Six-Minute Walk Test ( 6MWT ) is increasingly being used as a functional outcome measure for chronic pediatric conditions .
Knowledge about its measurement properties is needed to determine whether it is an appropriate test to use .
PURPOSE The purpose of this study was to systematic ally review all published clinimetric studies on the 6MWT in chronic pediatric conditions .
A step in the right direction: assessing exercise tolerance in cystic fibrosis.
Exercise tolerance may be reduced in patients with cystic fibrosis , but it is not always possible to predict this from st and ard lung function measurements . Formal exercise testing may , therefore , be necessary , and the test should be simple and readily available . We have developed a " 3-minute step test " and compared it with the st and ard 6-minute walking test . Subjects stepped up and down a 15-cm-high single step at a rate of 30 steps per minute for 3 minutes . The effect of the step test on spirometry was tested first in 31 children with CF ( mean age , 12.0 years ) , who had a mean ( range ) baseline forced expired volume in 1 second ( FEV1 ) of 64 % ( 18 - 94 % ) of predicted values . The step test was then compared with the st and ard 6-minute walk in a further 54 patients with cystic fibrosis ( mean age , 12.5 years ) , with mean ( range ) baseline FEV1 of 61 % ( 14 - 103 % ) of predicted values . Outcome measures were minimum arterial oxygen saturation ( SaO2 ) , maximum pulse rate , and the modified Borg dyspnea score . Post-step test spirometry showed mean ( 95 % CI ) changes of -1.1 % ( -6.0 + 3.9 % ) for forced vital capacity , of -1.6 % ( -4.2 + 1.1 % ) for FEV1 , and + 0.25 % ( -2.8 + 3.3 % ) for peak expiratory flow , although 5/31 children showed > 15 % drop in one or more parameters . The step and walk tests both produced significant changes ( P < 0.0001 ) in all outcomes , with a mean ( range ) minimum SaO2 of 92 % ( 75 - 98 % ) versus 92 % ( 75 - 97 % ) , a maximum pulse rate of 145 b.p.m . ( 116 - 189 ) versus 132 ( 100 - 161 ) , and a Borg score of 2.5 ( 0 - 9 ) versus 1.0 ( 0 - 5 ) , respectively . Comparison of the two tests showed that the step test increased breathlessness ( mean change Borg score , 2.3 vs. 0.8 ; P < 0.0001 ) and pulse rate ( mean change , 38 % vs. 24 % , P < 0.0001 ) significantly more than the walk , whereas the decrease in SaO2 was similar ( mean change , -2.9 % vs. -2.6 % ; P = 0.12 ) . Some patients with a significant drop in SaO2 ( > 4 % ) would not have the decrease predicted from their baseline lung function . Reproducibility for the two tests was similar . The step test is quick , simple and portable , and is not dependent on patient motivation . Although the step test is more tiring , its effect on SaO2 is similar to the 6-minute walking test . It is a safe test that may prove to be a valuable measure of exercise tolerance in children with pulmonary disease , although longitudinal studies are now needed
Limited evidence to strong evidence was found for reliability in various chronic conditions .
Little evidence was available for responsiveness and measurement error .
Studies showed large variability in test procedures despite existing guidelines for the performance of the 6MWT .
Evidence for measurement properties of the 6MWT  varies largely among chronic pediatric conditions .
BACKGROUND The Six-Minute Walk Test ( 6MWT ) is increasingly being used as a functional outcome measure for chronic pediatric conditions .
Knowledge about its measurement properties is needed to determine whether it is an appropriate test to use .
PURPOSE The purpose of this study was to systematic ally review all published clinimetric studies on the 6MWT in chronic pediatric conditions .