2.2. Study Design and Procedures
The baseline assessments for the ACTIVE study were conducted between March 1998 and October 1999, and a 10-year follow-up was completed in December 2010. Prior to randomization, baseline cognitive and physical functions, lifestyle factors, and health assessments were conducted. The initial cognitive training interventions consisted of ten 60-to-75 min, trainer-led sessions administered over six weeks conducted in group settings. All intervention materials were developed by the research team. The follow-up assessments were conducted approximately two months (i.e., posttest), one year, two years, three years, five years, and 10 years after baseline testing. The compliant training arm participants (i.e., completed at least 8 of 10 sessions) were further randomized to either receive four booster sessions prior to the assessments in years one and three (totaling 8 possible booster sessions) or received no booster training.