Naktal Muzahem Khaleel, Songol Bilal Murad and Wissam Mahdi Saleh 2022. USING VARIABLE RATIOS IN PERIODS OF WORK TO REST AND ITS REFLECTION TO DEVELOPING SOME PHYSICAL VARIABLES FOR HANDBALL PRACTITIONERS AGED 40-50 YEARS. ResearchJet Journal of Analysis and Inventions. 3, 06 (Jun. 2022), 1–12. DOI:https://doi.org/10.17605/OSF.IO/FV7W4.