The purpose of this study is to assess the effects of an aerobic and strength training exercise program (one that increases the need for oxygen and increases muscle) on the treatment outcomes of 150 individuals in treatment for methamphetamine dependence at Cri-Help. The study will determine if a 60-minute exercise program (three times a week) has an effect (good or bad) on the health and drug use of participants as compared to individuals not participating in an exercise program.