Its principle is, a heel, clamped with the tip uppermost and the stem approximately vertical, is subjected repeatedly to measured blows from a pendulum striker , the energy of the blows increasing successively until the heel fails. While the method is applicable to all types of high heels ,of whatever construction, it is particularly useful for injection molded plastics heels which incorporate a steel dowel reinforcement, giving information on the suitability of the dowel's hardness or softness.