Abstract

Background. Core stability is essential for effective movement and the prevention of low back pain, with the deep abdominal muscles, particularly the transverse abdominis, playing a central role. Their activation is closely linked to breathing. Different exhalation methods influence intra-abdominal pressure and, consequently, core stability. Although many studies have examined the activation of deep abdominal muscles during exercise, the impact of specific breathing strategies on their activity remains understudied. We aimed to determine how various exhalation methods affect the electrical activity of the deep abdominal muscles.

Methods. The study included 20 healthy female subjects aged 20 to 25 years who met the predefined inclusion and exclusion criteria. Deep abdominal muscle activation was measured using surface electromyography of the transversus abdominis muscle during different exhalation patterns in the supine position. Measurements were performed in a single visit following a standardised breathing ratio (inhale:exhale = 3:5), and the data obtained were normalised and statistically processed using nonparametric tests.

Results. The results showed statistically significant differences in the electrical activity of the deep abdominal muscles between different exhalation methods (p < 0.05). The highest values were recorded during voluntary activation of the abdominal muscles during exhalation (tightening the waist and pulling the navel in as far as possible), and the lowest during passive and phonatory exhalations. Exhalation with phonation SH was functionally more similar to exhalation through the nose than to exhalation with lip support. Pairwise comparisons showed statistically significant differences, particularly between voluntary and passive and phonatory modes of exhalation, with large effect sizes (|d| ≥ 0.8).

Conclusion. Different methods of exhalation and voluntary activation of the abdominal muscles affect the functioning of the deep abdominal muscles and core stability. Voluntary activation promotes more coordinated functioning of the core and stabilising muscles, contributing to improved body control and controlled movement. New insights into exhalation methods can contribute to the design of rehabilitation and physical exercise programmes. In the future, it would be useful to expand the research to a broader and more diverse sample, including individuals with various musculoskeletal problems, to better evaluate the long-term effects and clinical applicability of the findings.