Pengaruh Frekuensi Olahraga Futsal Terhadap Kebugaran Jasmani, Neuroplastisitas, Stres Fisik Dan Stres Oksidatif Pada Anak Usia Remaja (Kajian terhadap Komponen Kebugaran Jasmani, Atensi, Memori, Kadar BDNF, IGF-1, Kortisol dan MDA) = The Effect Of Futsal Sports Frequency On Physical Fitness, Neuroplasticity, Physical Stress, And Oxidative Stress In Adolescents (Study of Components of Physical Fitness, Attention, Memory, BDNF Levels, IGF-1, Cortisol, and MDA)