Background:  Down syndrome is the most common genetic intellectual disability conditions in 1 out of 800 to1000 live births. Adolescents and youth with Down syndrome are unique population on physical fitness factors related to health.

Method: To investigate the factors of physical fitness and physical activity in adolescents and youth with Down syndrome the international and national data bases such as EBSC, Medline, PubMed،Elsevier، Google scholar, SID from 1996 to 2016 were used. In this research, some Persian and English key words like physical fitness, physical activity, Down syndrome, rehabilitation, intellectual disability, muscular strength, muscular endurance, aerobic fitness, balance, agility and flexibility, were used.

Search of resources determined 130 articles that finally 35 articles were considered for the study.

Results: The results indicated that reduced cardio-respiratory capacity, lower level of physical protrusions and physical fitness in people with Down syndrome is significantly common. Related activities to health are also in low rate.

Conclusion: Future studies have to focuses on power tests and exercise programs, procedures of determining physical activities and practical intervention