Activity of the transverse abdominis muscle and its role in lower trunk stability and injury prevention in strength training men and football players

Background
The transverse abdominis muscle (TrA) is the deepest local stabilizer within the lumbopelvic-hip complex, distinguished by its feedforward activation pattern and significant role in the prevention of lower back pain. Its activity may indirectly contribute to injury prevention in both the lower trunk and the lower limbs.

Aims
This study aimed to evaluate the activity of the transverse abdominis muscle and its role in lumbar spine control and injury prevention in strength-training males and football players.

Material and methods
Forty-four men participated in the study, including 22 strength trainers and 22 football players. Body composition analysis using bioelectrical impedance, trunk stability tests (Functional Movement Screen: trunk stability push-up and rotary stability tests), ultrasound assessment of the transverse abdominis muscle at rest and during activation, and tests for uncontrolled movements of the lumbopelvic-hip complex using a Pressure Biofeedback Stabilizer following the Kinetic Control concept were conducted. Results: In the strength-training group, the activation coefficient and percentage (%) change in TrA thickness were symmetrical, with values comparable to the left-side TrA activation among football players. On the right side, football players demonstrated a lower degree of activation. Significant asymmetry in TrA activation, greater on the left side, was observed only among football players. The resting cross-sectional area of the TrA [mm] showed no correlation with activation coefficients, except for moderate statistical associations observed on the right side among football players. No significant correlations were found between tests assessing the stability of the lumbopelvic-hip complex and either the resting TrA thickness [mm] or the degree of TrA activation.

Results
Forty-four men participated in the study, including 22 strength trainers and 22 football players. Body composition analysis using bioelectrical impedance, trunk stability tests (Functional Movement Screen: trunk stability push-up and rotary stability tests), ultrasound assessment of the transverse abdominis muscle at rest and during activation, and tests for uncontrolled movements of the lumbopelvic-hip complex using a Pressure Biofeedback Stabilizer following the Kinetic Control concept were conducted.

Conclusions
Since thick muscle fibers hinder oxygen diffusion, the cross-sectional area of the TrA—which requires aerobic conditions for sustained activity—may be less critical compared to muscle activation occurring at low thresholds (up to 25% MVC). The observed asymmetry in TrA activation between body sides likely reflects the specific demands of physical activities. Due to its stabilizing function, this muscle may indirectly contribute to injury prevention in the trunk and lower extremities