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This study aimed to explore the effect of walkway length and shape on the distance during the six-minute walk test (6MWT) among healthy adults aged 20-30 years.
This was a cross-sectional observational study. Totally 36 young healthy subjects were enrolled in the Sun Yat-sen university from December 17th, 2016 to February 26th, 2017. Subjects recruited were instructed to undertake five 6MWTs with different lengths and shapes at a random sequence, with a 20-minute rest interval between every two tests. The five protocols designed in this study included 15-meter, 30-meter, 45-meter straight walkway, a 60-meter oval walkway and a 60-meter square walkway. The primary outcome measure, six-minute walk distance (6MWD), was recorded during each test. Other parameters including oxygen saturation(SPO2), heart rate(HR), systolic blood pressure(SBP), diastolic blood pressure(DBP), dyspnea and leg fatigue were measured at baseline and immediately after each 6MWT. SPO2, HR and dyspnea were also assessed during walking. All data were computed with SPSS windows 20.0.
Thirty-six healthy adults (13 males, 23 females; mean age: 21.28 ± 1.95 years; mean height 1.64 ± 0.84m; mean weight 55.83 ± 7.65 kg; mean BMI, 20.67 ± 1.66 kg/m2) were recruited. The 6MWDs collected in five protocols were 615.94 ± 66.78m (15-meter straight walkway), 630.00 ± 57.15m (30-meter straight walkway), 641.08 ± 60.38m (45-meter straight walkway), 633.50 ± 59.47m (60-metersquare walkway) and 644.11 ± 61.44m(60-meter oval walkway), respectively. The longest 6MWD was recorded in the 45-meter walkway (645.11 ± 61.44m).
The 6MWDs were significantly different between 30-meter straight and 15-meter straight walkway (p = 0.005), 30-meter straight and 45-meter straight walkway (p = 0.007), 15-meter straight and 45-meter straight walkway (p < 0.001), 30-meter straight and 60-meter oval walkway (p < 0.001), while there were no significant differences between 30-meter straight and 60-meter square walkway (p= 0.0428), 60-meter square and 60-meter oval walkway (p= 0.021), compared by paired t-test with a Bonferroni correction (α = 0.05/6 = 0.0083). No significant differences of cardiopulmonary variables (SPO2, HR, BP) and perceived exertion (dyspnea and leg fatigue) were found at baseline, during walking and in the recovery phase among all five protocols.
This study suggests that both the walkway length and shape have a significant effect on the 6MWD. The shorter walkway length during the walk test results in a shorter 6MWD. For the same circumference, a continuous walkway can induce a longer 6MWD. Hence, it is recommended that a standard walkway length and shape should be used in order to obtain a reliable measurement of functional capacity in clinical practice.