Comparative analysis of tensiomyographic and isokinetic assessments of the rectus abdominis and erector spinae in bodybuilding trainees with nonspecific low back pain.

Background: Bodybuilding training places a significant load on the lumbar region, making it prone to nonspecific low back pain (NSLBP). This study aimed to examine the associations between tensiomyography (TMG) parameters-contraction time (Tc), relaxation time (Tr), delay time (Td), maximum displacement (Dm), and sustain time (Ts)-and isokinetic dynamometric measures, including peak torque (PT) and work per repetition (WR), in trunk muscles of bodybuilding trainees with NSLBP. Methods: A total of 150 participants were allocated to a control group (n = 60) and the NSLBP group (n = 90). Pain severity from NSLBP was evaluated using the Numerical Pain Rating Scale and the Roland-Morris Disability Questionnaire. Daily calorie intake, assessed using an artificial intelligence (AI) camera, and physical activity levels, calculated through a standardized equation website, were averaged weekly and analyzed monthly. The muscle function of the rectus femoris and erector spinae was first assessed using TMG, followed by a 30-minute rest period before performing trunk flexion and extension tests with an isokinetic dynamometer. Results: This study revealed that the parameters assessed using TMG and isokinetic equipment were lower or indicated greater weakness in the NSLBP group compared to the control group. Tc, Tr, and Td showed negative correlations with PT and WR, whereas Dm and Ts were positively associated. The NSLBP group demonstrated significantly longer Tc, Tr, and Td, along with lower Dm, Ts, PT, and WR values. These findings suggest that TMG variables, which assess muscle function at rest, are associated with the torque parameters measured by isokinetic dynamometry during movement. Bodybuilding trainees with a history of NSLBP exhibit impairments in both static and dynamic muscle function, indicating the need for stability-focused interventions during training.