A health education intervention as the control condition in the CTN-0037 STRIDE multi-site exercise trial: Rationale and description

• Rationale for a health education intervention (HEI) control condition.
• Advantages of using the HEI in exercise trials assessing psychological outcomes.
• Careful design of the HEI to ensure proper implementation.
• Discussion of alternative control conditions considered.

The selection of a control condition in a randomized controlled trial (RCT) is critical in determining the effect of the experimental treatment. While the use of a placebo pill can be an ideal control in pharmaceutical trials, RCTs of behavioral interventions present unique challenges in the selection and implementation of the appropriate control condition. Investigators must not only consider the control condition's ability to protect against threats to internal validity and its plausibility as a possible intervention, but must also carefully implement the control condition so it does not introduce bias from either the investigators or the participants. The purpose of this paper is to provide the rationale for the use of a health education intervention (HEI) as the control condition in the CTN-0037 Stimulant Reduction Intervention Using Dosed Exercise (STRIDE) trial. In this paper, we will describe the careful design of the HEI to ensure proper implementation and discuss alternative control conditions considered.Clinical trials registry: clinicalTrials.gov, NCT01141608, http://clinicaltrials.gov/ct2/show/NCT01141608.