Cushioning effect of heel cups

Three types of heel cups, two rubber and one plastic, were evaluated in this study. The vertical forces under the heel were monitored using the Computer Dyno Graphy system in 16 normal subjects. Peak force reduction in walking and running after heel cup use was found for all three types of heel cups. The shock absorbency (peak force reduction as a ratio) of heel cups was better in walking (3.5 km h^-1) than in running (10 km h^-1). Pressure-sensitive film under the heel revealed that the pressure concentration at the location of calcaneal tuberosity could be smoothed out by the use of heel cups. When plastic heel cups were used, pedobarography showed that the contact area of the heel while standing decreased to 61% of that when barefoot. Roentgenographic study in six patients with heel pain syndrome showed that the thickness of the heel pad increased from 14.4 mm (SD 1.4 mm) to 17.0 mm (SD 1.2 mm) when plastic heel cups were used.