The primary goal of this study is to provide comprehensive and objective information on impairments of musculoskeletal health, sensory function, and fitness among a large group of childhood ALL survivors, and to define high risk groups by assessing treatment factors that contribute to impaired function. This study includes a direct, objective evaluation of musculoskeletal function, sensory capacity, fitness, and physical activity patterns among adults who were treated for childhood ALL at St. Jude Children's Research Hospital (SJCRH) between 1980 and 1999. Among 899 ALL survivors, all of whom are eligible for an institutionally funded clinical study of medical late effects, the study will recruit 364 to participate in our evaluations. The study will also recruit 364 individuals for a comparison group, frequency matching on race/ethnicity, age and gender.