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Table 1 Summary of some distinguishing features among efficacy, effectiveness, and behavior change exercise trials.

From: Efficacy, effectiveness, and behavior change trials in exercise research

  Efficacy Trial   
  Traditional Contemporary Effectiveness Trial Behavior Change Trial
Primary Outcome: A health outcome A health outcome A health outcome An exercise behavior outcome
Secondary Outcomes: Other health outcomes Other health outcomes Other health outcomes Other behavior/health outcomes
Protocol Deviations: Not exercising Not exercising/behavioral support Not exercising/behavioral support Not completing behavioral support
Theoretical Model: Outcome model needed Outcome model needed Outcome model needed Outcome model not needed
  Behavior model not needed Behavior model beneficial Behavior model needed Behavior model needed
Participants: Highly selected Highly selected Moderately selected Variably selected
  Not exercising/limited exercise Not exercising/limited exercise Exercise levels reflective of practice Variable exercise levels
  Lower generalizability Lower generalizability Higher generalizability Higher generalizability
Exercise Intervention: Completely supervised Completely/partially supervised Unsupervised/partially supervised NA (exercise is the outcome)
  Precise exercise type/volume Partially flexible types/volumes Flexible exercise types/volumes Flexible exercise types/volumes
  Agree to exercise Agree to exercise Agree to exercise Asked to exercise
  No/limited behavioral support Agree to behavioral support Agree to behavioral support Agree to behavioral support
Behavioral Support Intervention: Minimal/informal Extensive/comprehensive Moderate/feasible for dissemination Varied but systematic and feasible
Comparison Intervention: No exercise intervention Minimal exercise intervention Standard of care At least exercise recommendation
  Agree not to exercise Allowed to exercise Allowed to exercise Asked to exercise
  No behavioral support No/limited behavioral support Behavioral support as per standard care Behavior support based on purpose
Sample Size: Powered for health outcome Powered for health outcome Powered for health outcome Powered for behavioral outcome
  No allowance for nonadherence Allowance for nonadherence Allowance for nonadherence No allowance for nonadherence
Analysis: Intention-to-treat Intention-to-treat Intention-to-treat Intention-to-treat
  Prespecified subgroup analyses Prespecified subgroup analyses Prespecified subgroup analyses Prespecified subgroup analyses
Interpretation of Results:
Positive trial Improves primary health outcome Improves primary health outcome Improves primary health outcome Improve primary behavior outcome
  Adequate exercise adherence Adequate exercise adherence Adequate exercise adherence Adequate support adherence
   Support adherence not required Support adherence not required  
Negative trial No change in health outcome No change in health outcome No change in health outcome No change in behavioral outcome
  Adequate exercise adherence Adequate exercise adherence Adequate exercise adherence Adequate support adherence
   Support adherence not required Support adherence not required  
Inconclusive trial No change in health outcome No change in health outcome No change in health outcome No change in behavioral outcome
  Inadequate exercise adherence Inadequate exercise adherence Inadequate exercise adherence Inadequate support adherence
Nature of the Result:
Definitive Negative trial Negative trial Positive trial Negative trial
  No effect in practice is likely No effect in practice is likely Effect in practice is likely No effect in practice is likely
Ambiguous Positive trial Positive trial Negative trial Positive trial
  Effect in practice is unknown Effect in practice is unknown Effect under better conditions unknown Effect on health outcomes unknown
     (unless shown in trial or literature)