This standard applies to the upper and lining materials of various types of footwear. It specifies test methods for assessing flex resistance under dry, wet, and low-temperature conditions, covering core aspects such as specimen preparation, environmental conditioning, operational procedures, and result evaluation. By simulating bending scenarios encountered during actual wear, the test subjects specimens to repeated flexing at specific angles and frequencies. The durability of the material is evaluated based on damage indicators such as cracking and delamination. Relevant testing instruments include a flex resistance tester (equipped with specialized clamps and precise control over swing angles and rates), a die cutter with dimensions of (70 ± 1) mm × (45 ± 1) mm, and an optical magnifier with 4–6× magnification. Wet condition testing requires a vacuum desiccator and glass dish, while low-temperature testing necessitates a specialized freezer to ensure coverage across different usage scenarios.