2017 年 83 巻 852 号 p. 17-00170
Of all occupational accidents in industries in Japan, the most frequently occurring accidents are falls. In conventional studies on falls, their characteristics have been evaluated by assessing balance on rapidly moving and steeply sloped floorboards considering that the main cause of falls is a decline in balance control. It is speculated that this decline is caused by the development of aging-related muscle weakness. However, resultant trauma to the back of the subject's head could not be replicated in the conventional studies on falls. Therefore, after deriving the physical equation of the fall model, we developed a new equipment for testing falls that simulates a fall consistent with the physical equation. Using this equipment, the test is started by opening a rope toggle, thereby causing the floorboard to suddenly move horizontally and downward at the same time. This equipment could achieve a backward rollover fall that results in hitting the back of the head of the subject, but safely without injury. It was thus possible to confirm that the fall rate was age- and work style-related and there was no relation with height. This study showed that it is possible to identify a decline in balance control as subjects get older using this equipment to execute a falling experience as part of regular safety education. By performing this test regularly, balance control in workers could be assessed and it was also understood that most falls are caused by diminishing balance control. In addition, it would be beneficial if workers exercised on a daily basis to reduce aging-related muscle-weakening effect.