Phimphasak, Chatchai, Rungthip Puntumetakul, Uraiwon Chatchawan, and Manida Swangnetr. 2012. “Comparison of sustain and dynamic back hyperextension exercises on spinal height in asymptomatic subjects: a pilot study”. Archives of Allied Health Sciences 24 (3). Khon Kaen, Thailand:327-38. https://he01.tci-thaijo.org/index.php/ams/article/view/66294.