Table 2– Effect of methodological variations on 6-min walking distance (6MWD)
Variation in methodologyStudies nFirst author [ref.]Effect on 6MWD
Hallway versus treadmill2Stevens [14]
de Almeida [15]
13–20% less on treadmill
Indoors versus outdoors1Brooks [16]4 m (1%) more outside
Circular versus straight track2Bansal [17]
Sciurba [18]
13–19 m (3–5%) more on circular track
Track length2Sciurba [18]
Beekman [19]
No statistically significant difference in 6MWD from tracks of 15–121 m
50 m more on 30-m track compared to 10-m track
Wheeled walking aid versus no aid6Gupta [20]
Honeyman [21]
Probst [22]
Roomi [23]
Solway [24]
Vaes [25]
Weighted mean 6.2% more with wheeled walker
Range 2–46 m more with wheeled walker
83 m more with modern draisine compared to wheeled walker
With versus without oxygen4Davidson [26]
Fujimoto [27]
Rooyackers [28]
Jolly [29]
12–59 m more with oxygen
Oxygen versus compressed air2Jolly [29]
McDonald [30]
17–109 m more with oxygen
Carry oxygen versus oxygen in wheeled cart1Crisafulli [31]23 m more with wheeled cart
Patient carries oxygen versus tester carries oxygen1Woodcock [32]24 m versus 35 m improvement
Encouragement1Guyatt [33]30.5 m more with encouragement
Instructions1Weir [34]53 m further when asked to walk as “fast” as possible, rather than as “far” as possible