2012 年 50 巻 6 号 p. 509-515
This study examined the changes in pressure pain in the upper trapezius muscle, cervical range of motion, and cervical flexion–relaxation ratio after overhead work. 14 workers were recruited. Pressure pain in the upper trapezius muscle, active cervical range of motion, and cervical flexion–relaxation ratio were measured in all subjects once before and once after overhead work. The pressure-pain threshold of the left upper trapezius muscle was 8.6 ± 2.5 lb before overhead work and 7.3 ± 2.4 lb after overhead work; that of the right upper trapezius muscle was 8.8 ± 2.9 and 7.3 ± 2.8 lb, respectively, revealing a significant decrease in pressure-pain threshold with overhead work. All cervical range of motion measures decreased significantly with overhead work. The cervical flexion–relaxation ratio on the left side was 1.3 ± 0.2 before overhead work and 1.1 ± 0.2 after overhead work; the respective values for the right side were 1.4 ± 0.5 and 1.2 ± 0.3 before and after overhead work, revealing a significant decrease with overhead work. We postulate that overhead work can reduce the pressure-pain threshold in the upper trapezius muscle and cause changes in the cervical range of motion and cervical flexion–relaxation ratio.