Baseline characteristics (n = 127).

Trial design
This was a 2×2 randomized crossover control trial.
Objective
To compare the cardiovascular endurance of healthy volunteers using a 2-minute marching test (2MMT) and a 6-minute walk test (6MWT).
Methods
This study included 254 participants of both sexes, aged 20–50 years, with a height and body mass index (BMI) of ≥150 cm and ≤25 kg/m2, respectively. Participants were hospital staff who could perform activities independently and had normal annual chest radiographs and electrocardiograms. A group-randomized design was used to assign participants to Sequence 1 (AB) or 2 (BA). The tests were conducted over 2 consecutive days, with a 1-day washout period. On day 1, the participants randomly underwent either a 6MWT or 2MMT in a single-anonymized setup, and on day 2, the tests were performed in reverse order. We analyzed maximal oxygen consumption (VO2max) as the primary outcome and heart rate (HR), respiratory rate (RR), blood pressure (BP), oxygen saturation, dyspnea, and leg fatigue as secondary outcomes.
Results
Data were collected from 127 participants, categorized into two groups for different testing sequences. The first (AB) and second groups had 63 and 64 participants, respectively. The estimated VO2max was equivalent between both groups. The 2MMT and 6MWT estimated VO2max with a mean of 41.00 ± 3.95 mL/kg/min and 40.65 ± 3.98 mL/kg/min, respectively. The mean difference was -0.35 mL/kg/min (95% confidence interval: -1.09 to 0.38; p <0.001), and no treatment and carryover effect were observed. No significant changes were observed in HR, RR, and systolic BP (p = 0.295, p = 0.361 and p = 0.389, respectively). However, significant changes were found in the ratings of perceived exertion (p <0.001) and leg fatigue scale (p <0.001).
Conclusion
The 2MMT is practical, simple, and equivalent to the 6MWT in estimating VO2max.
Trial registration
TCTR20220528004https://www.thaiclinicaltrials.org.