Generally, safety helmets are not the preferred device to be worn by users. Some users develop mental discomfort and unease caused by the head temperature rising above normal, excess perspiration or oppression when wearing a helmet. These disadvantages, which are incidental to the existing helmets, are brought about by designs which are developed to provide the strength of materials.
　A systematic study, together with related experiments, has been launched and proceeded in order to remove the unpleasantness described above by using a bicycle ergometer, an infrared imaging unit and other testing devices.
　As a result, the following experimental conclusions have been obtained: The surfaces of a human head (when bald) without the helmet showed rather complicated thermal distribution during the pedaling test, with both the heart rate and temperature increased like a saturation curve to the pedaling time. The helmet with ventilation holes covering the high temperature area of the head was effective enough, not only to cool down the heat of the head, but also to satisfy the strength required by JIS (Japanese Industrial Standard).
　Air flows around the helmet placed on a head model of a mannequin were visually identified by the surface tuft and smoke wire technique in a low -velocity smoke tunnel.
　Besides, the mechanical properties gained the process that glass microspheres are filled into the basic materials (polypropylene) have been identified by using various testing devices.
　Therefore, future safety helmets are expected to be designed more rationally based upon these experimental data.

DESCENTE SPORTS SCIENCE Vol.19/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE