Abstract

Low back pain (LBP) is highly prevalent within the athletic population despite increased training and intensity. Quality activation of the lumbar musculature is crucial for proper stabilization during athletic movements. Extensive research has indicated a connection between lumbar multifidus (LM) muscle morphology (cross-sectional area (CSA), echo intensity (EI), and CSA asymmetry) and function and the presence of LBP and lower limb injury (LLI) in athletes. However, LM has only been examined in small sample sizes through single sport investigations. Furthermore, body composition has been closely related to skeletal muscle characteristics, yet few studies have examined the influence of body composition parameters on LM morphology and function. Therefore, the purpose of this work was to 1) investigate if LM morphology and function are predictors of LBP and LLI in a large sample of university varsity athletes and 2) examine the relationship between LM characteristics and the body composition in university athletes.

A total of 134 university level athletes were included in this study and completed a self-reported questionnaire to acquire data on demographics and history of LBP and LLI. LM characteristics at the 5th lumbar vertebra were assessed via ultrasound and body composition was assessed via dual energy x-ray absorptiometry (DEXA). Manuscript 1 investigated LM morphology and function via ultrasound and the presence of LBP and LLI in the past year via questionnaire. Manuscript 2 examined body composition via DEXA, LM morphology and function via ultrasound, and type of sport via questionnaire.

Overall, LM was larger and thicker on the non-dominant side of the lower limb in males. LM thickness was the best predictor of the presence of LBP and type of sport was the best predictor of the presence of LLI. LM cross-sectional area and thickness were both positively correlated with several body composition measurements and echo intensity, and total fat mass, and % body fat were negatively correlated with % thickness change of the LM.

This study investigated the relationships between LM, LBP, LLI, and body composition. Using ultrasound to assess LM characteristics may be a tool for team health professionals to perform preseason screening to identify athletes at risk for injury and develop individualized rehabilitation programs for injury prevention.