High-intensity resistance training (RT) shows promise for improved cardiometabolic health in children. Achieving high-intensity RT safely is a challenge for community-based programs because of parental concerns and group engagement. Twenty preadolescent children completed an 8-week, twice per week program using slow speed to achieve high-intensity RT. Parent and child surveys were conducted to measure acceptability and effectiveness. Child fitness levels were assessed, and fasting blood draws and dual-energy x-ray absorptiometry were performed on a subset population. Perceived RT safety, self-efficacy, body composition, waist circumference, and fitness tests exhibited significant improvements. Using slow speed to achieve high-intensity RT may provide a safe and effective community-based alternative for preadolescents.