The purpose of this study was to investigate the influence of different respiratory resistance on the activations of the core muscles in healthy adults.
A total of 22 healthy adults participated in this study. Their maximal inspiratory and maximal expiratory pressures (MIP and MEP) were measured respectively for setting different levels of respiratory resistance including no, medium (40% of MIP or MEP), and high levels (100% of MIP or MEP). A series of ultrasonography images of lateral abdominal muscles (EO, IO, TA), DM, and lumbar MF under three different respiratory resistances provided by a DofinTM breathing trainer DT14 (GaleMed Corporation, 2023) were recorded, respectively. Repeated measures ANOVA was used for statistical analysis.
The results showed that most of the core muscles became thinner in order to counteract the respiratory resistance, suggesting an eccentric activation strategy. The activations of the DM were significantly increased under both medium- and high-resistance compared to the no-resistance condition. The activations of all abdominal muscles including the EO, IO, and TA muscle were significantly higher under the high- resistance compared to the medium- and no-resistance conditions. The activation of lumbar MF was significantly higher in the medium-resistance compared to the high- and no-resistance.
This study proved that the activation of the DM increased with increased respiratory resistance. However, a medium to high level of respiratory resistance, at least greater than 40% of MEP or MIP may be needed to induce higher activations of the MF and abdominal muscles. The findings support the notion that superficial core muscles such as IO and EO being only recruited during the high loading tasks. Further study such as targerting other core muscles or protocol of core muscle via respiratory resistance is needed.
This study demonstrated that respiratory muscle training also induced other core muscle activations and may be used in clinical.This study demonstrated that respiratory muscle training also induced other core muscle activations and may be used in clinical.
core muscle
respiratory resistance