The Strength Shoe is a modified athletic shoe with a 4-cm thick rubber platform attached to the front half of the sole. It is promoted as an effective method of increasing "speed, quickness, and explosive power," as well as ankle flexibility and calf circumference, when used in a plyometrics-based training regimen. This study evaluates, in a prospective, randomized trial, the efficacy and safety of the Strength Shoe training regimen for increasing lower leg flexibility and strength in intercollegiate track and field participants. No enhancement of flexibility, strength, or performance was observed for participants wearing the Strength Shoe at the end of an 8-week training program, following the suggested regimen of the manufacturer. The use of the Strength Shoe cannot be recommended as a safe, effective training method for development of lower leg strength and flexibility. However, the use of plyometrics in a properly supervised setting may improve athletic performance and merits further investigation.