Pengaruh latihan fisik saat hemodialisis terhadap kadar ureum dan kreatinin pada pasien Penyakit Ginjal Tahap Akhir (PGTA) di RSUD Dr. Achmad Mochtar Bukittinggi = Effect of physical exercise during hemodialysis on levels of urea and creatinine in patients with end stage renal disease at RSUD Dr. Achmad Mochtar Bukittinggi