A pragmatic multi-setting lifestyle intervention to improve leisure-time physical activity from adolescence to young adulthood: the vital role of sex and intervention onset time.

This study is registered at Iran Registry for Clinical Trials (IRCT), a WHO primary registry ( http://irct.ir ). The TLGS clinical trial was the very first registration in the IRCT (Iran Registry of Clinical Trials). it was registered on 2008-10-29 by the registration number IRCT138705301058N1 . Based on the international committee of medical journal Editors (ICMJE), "retrospective registration" is acceptable for trials that began before July 1, 2005.