Functional and structural effects of local vs. global motor control training: An ultrasound-based study on deep abdominal muscles.

BACKGROUND

Trunk stabilization is essential in rehabilitation and sports training, relying on anticipatory activation of deep trunk muscles like the transverse abdominis.

OBJECTIVES

This study assessed the effects of 4-week motor control training programs (global and local) on lateral abdominal wall muscle thickness and functional parameters.

METHODS

Fifty-eight participants were enrolled, and forty-eight (35 women, 13 men) completed the study. Inclusion criteria were: age 18-40 years, BMI ≤29.9, and no contraindications to training. Participants were randomly assigned to global training (GT), local training (LT), or control (CG). The intervention lasted four weeks, with GT using a Pressure Biofeedback Stabilizer and LT using sonofeedback. Muscle thickness was assessed by ultrasound, trunk mobility with Fingertip-to-Floor and Sit-and-Reach tests, and jump performance via CMJ. Statistical analyses used Wilcoxon and Kruskal-Wallis tests.

RESULTS

Global training (GT) significantly increased lateral abdominal muscle thickness (TrA: +0.7 cm, IO: +0.1 cm, EO: +0.06 cm; p < 0.01) and showed greater improvements in combined abdominal muscle thickness than both LT and CG. Local training (LT) demonstrated a near-significant increase in transverse abdominis thickness (+0.3 cm; p = 0.07). No significant changes were observed in trunk mobility or jump performance (p > 0.05). Ultrasound transducer positioning (parallel vs. perpendicular) affected measurement reliability for oblique muscles.

CONCLUSIONS

Global training led to hypertrophic changes in lateral abdominal muscles. Local training showed a trend toward increased transverse abdominis thick-ness but without statistical significance. Ultrasound measurements may be less reliable when the transducer is positioned parallel to the body midline.