Abstract
[Purpose] It is well-known that the muscles of spinal stability also play roles in respiration. The spinal stability muscles are divided into two subgroups, the local muscle group and the global muscle group. Appropriately coordinated activation of muscle groups are recommended for more efficient spinal stability. The indirect method of measuring coordination of muscle groups is the synergist ratio of local muscles to global muscles. The purpose of this study was to investigate the synergist ratios of the spinal stability muscles of different breathing patterns. [Subjects and Methods] Forty healthy subjects performed 4 different breathing patterns and 3 synergist ratios calculated from % maximal voluntary isometric contraction of 2 local group muscles and 3 global group muscles were analyzed. [Results] The results of this study show synergist ratios were consistent among the breathing patterns and there was a consistent muscle reliance pattern of synergist ratios during each breathing pattern. The synergist ratio of extensors stayed around 1. The results were consistent with those of previous studies of spinal stability exercises. [Conclusion] We suggest that different breathing patterns could be used as a component of spinal stability exercises, secondary to the similarities of muscle coordination with spinal stability exercises, commonly used in clinics.