The pelvic drop can indicate a sign of muscle weakness during the lumbopelvic stability test. The integrity of this region ensures the proper transfer of energy to the distal segments for the body's kinematics and biomechanics, such as muscle strength, which is an important component of the kinetic chain. In swimming athletes, it is not yet clear which factors may be related to the injuries and pain they experience, making it necessary to understand if there is any correlation between the lumbopelvic stability test and trunk muscle endurance due to the scarcity of studies.

To assess the correlation between the lumbopelvic stability test and endurance tests of the trunk in swimmers.

This was a cross-sectional observational study approved by the research ethics committee. The inclusion criteria were swimmers athletes of both sex, age between 18 and 60 years old, with competitive practice in the past one year, and regular training for at least twice a week. Lumbopelvic stability was assessed using the one-legged bridge test with spherical markers on the anterior superior iliac spines, where the pelvic tilt (in degrees) was observed and recorded. Two-dimensional analyses were conducted using the Kinovea 0.9.5 software (Kinovea Open Source Project) for Windows®. Additionally, muscle endurance of the trunk flexors (front plank), extensors (Biering-Sorenson test), and lateral flexors (side plank) was assessed by having the individual maintain a pre-established ideal posture for each muscle group for as long as possible. Pearson coefficient correlation was used to assess the association between the lumbopelvic stability test and endurance tests, which was classified as weak (0–0.39), moderate (0.40–0.69), and strong (0.70–1.00). Data analysis was performed using SPSS Inc, Chicago, IL version 23.0.

A total of 27 athletes participated in the study, with mean age of 32.78 ± 14.64, 6.96 ± 6.05 years of sports practice, and 15 (56 %) were men. The results of the lumbopelvic stability test showed a weak negative correlation for the endurance of the flexor muscles (front plank) (r = - 0.233), right lateral flexors (side plank) (r = - 0.217), left lateral flexors (side plank) (r = - 0.003), and a weak positive correlation for the trunk extensor muscles (Biering-Sorenson test) (r = 0.109).

The lumbopelvic stability test has a weak negative correlation for the endurance of the flexor muscles, lateral flexors, and a weak positive correlation for the trunk extensor muscles in swimming athletes.

The study suggests that endurance does not influence pelvic tilt during the lumbopelvic stability test in swimming athletes, and therefore, it is important to investigate and evaluate other factors that may actually influence instability in this region.