Limitations
The present trial has some limitations. First, the number of participants in the control group that completed the study was lower than indicated in the power calculations. As a consequence, the power might have been insufficient to detect the expected effects and effect estimates might be biased. Stratified analyses should be regarded as exploratory. Second, the number of participants in the intervention group that achieved the intended improvement in physical activity was too low, suggesting the intervention was feasible but not effective enough to establish a significant change in physical activity in most of the participants. Third, converting non-ambulatory activities to steps, according to the criteria of Tudor-Locke and Basset [