The Effect Of Elderly Exercise On Vo2max Levels In The Elderly Using Fabric Mask And Surgical Mask In Sidodadi Village, Deli Regency, Serdang In The New Normal Era. JKF [Internet]. 2022 Apr. 28 [cited 2025 Jul. 1];4(2):272-8. Available from: https://ejournal.medistra.ac.id/index.php/JKF/article/view/955