The ability of elevated heels of ladies shoes and sandals to withstand repeated lateral impacts without breaking off is determined by holding the heel in a suitable holder and giving repeated impacts of specified impact energy near its lower edge. The test is continued till the time the heel fractures, or till a total number of 20,000 impacts is given to the heel under test. The number of impact after which the heel fractures gives a measure of the Fatigue Resistance of the heel under test.
ISO 19956 – 2004 : Footwear – Test Methods for Heels – Fatigue Resistance
SATRAPM21 – 1988 : Fatigue Test for Shoe Heels
BS5131(Section4.9) – 1991 : Method of Test for Footwear and Footwear Materials
Section 4.9:Fatigue Resistance of Heels of Ladies Shoes