3 research outputs found
Evidence for the different physiological significance of the 6- and 2-minute walk tests in multiple sclerosis
Background: Researchers have recently advocated for the 2-minute walk (2MW) as an alternative for the 6-minute
walk (6MW) to assess long distance ambulation in persons with multiple sclerosis (MS). This recommendation has
not been based on physiological considerations such as the rate of oxygen consumption (V路O2) over the 6MW
range.
Objective: This study examined the pattern of change in V路O2 over the range of the 6MW in a large sample of
persons with MS who varied as a function of disability status.
Method: Ninety-five persons with clinically-definite MS underwent a neurological examination for generating an
Expanded Disability Status Scale (EDSS) score, and then completion of the 6MW protocol while wearing a portable
metabolic unit and an accelerometer.
Results: There was a time main effect on V路O2 during the 6MW (p = .0001) such that V路O2 increased significantly
every 30 seconds over the first 3 minutes of the 6MW, and then remained stable over the second 3 minutes of the
6MW. This occurred despite no change in cadence across the 6MW (p = .84).
Conclusions: The pattern of change in V路O2 indicates that there are different metabolic systems providing energy
for ambulation during the 6MW in MS subjects and steady state aerobic metabolism is reached during the last 3
minutes of the 6MW. By extension, the first 3 minutes would represent a test of mixed aerobic and anaerobic
work, whereas the second 3 minutes would represent a test of aerobic work during walking
Participant demographics as a function of group.
<p>Participant demographics as a function of group.</p