Background

Trunk stabilization training is widely used in physiotherapy to improve activation of deep trunk muscles, particularly the transversus abdominis (TrA). Short-term morphological effects of such interventions remain inconclusive.

Aims

To evaluate the effect of a four-week local stabilization training programme using sonofeedback on lateral abdominal muscle wall thickness, and to assess the reliability of ultrasonographic measurements.

Material and methods

Twenty-nine healthy adults were randomly assigned to a local training (LT) group or a control (CG) group. Ultrasonographic measurements of TrA and lateral abdominal wall
muscles were performed before and after the intervention. The LT group completed a four-week stabilization programme with sono-feedback; the CG maintained usual physical activity. Non-paramet-ric tests and intraclass correlation coefficients (ICC) were used for statistical analysis.

Results

No baseline differences were observed between groups. In the LT group, a tendency toward increased TrA thickness was observed after the intervention (approximately 0.3 mm; p ≈0.07). No significant changes were found in the internal or external oblique
muscles or in the control group. ICC values were approximately 0.99 (TrA), 0.97 (internal oblique), and 0.88 (external oblique), confirming very high measurement reliability.

Conclusions

Four weeks of local stabilization training with sonofeedback were associated wit
a tendency toward increased TrA thickness. Ultrasonography proved to be a reliable method for assessing lateral abdominal wall muscle thickness.