Lumbar Multifidus Characteristics in University Level Athletes May be Predictors of Low Back Pain and Lower Limb Injury

Abstract

Background Low back pain (LBP) is highly prevalent in athletes, with lumbar multifidus (LM) atrophy and increased LM cross-sectional area (CSA) reported in athletes with LBP. Decreased LM CSA and thickness have also been previously associated with lower limb injury (LLI) in athletes. Yet, previous research has only investigated connections between LM, LBP, and LLI in small samples of athletes in a single sport at a time. The current study aimed to (1) examine LM morphology and function across a general sample of male and female university level varsity athletes; (2) investigate whether LM characteristics were predictors of LBP and LLI. Methods Exclusion criteria included previous severe spinal trauma or spinal fracture, spinal surgery, observable spinal abnormalities, and pregnancy. Ultrasound images of LM at L5 were acquired in prone and standing. Body composition was assessed with DEXA and a self-reported questionnaire provided demographics and history of injury. Paired t-tests and independent t-tests compared LM measurements between the sides and sex, respectively. Univariate and multivariate logistic regression analyses were used to assess if LM characteristics were predictors of LBP and LLI. Results 134 university varsity athletes (mean age, 21.0 ± 1.5, 84 male) were evaluated. LM CSA was larger on the non-dominant side in both males (non-dominant, 10.54 ± 1.55, dominant, 10.34 ± 1.58, p < 0.05) and females (non-dominant, 8.26 ± 1.32, dominant, 8.11 ± 1.33, p < 0.05) in prone. Increased LM thickness was associated with decreased odds of LBP in the previous 4-week (OR = 0.49 [0.27, 0.88], p = 0.02) and 3-month (OR = 0.43 [0.21, 0.89], p = 0.02) in the multivariable model, while a greater number of years playing at the university level was associated with increased odds of LBP (OR = 1.29 [1.01, 1.65], p = 0.04). Greater LM CSA asymmetry (OR = 1.14 [1.01, 1.28], p = 0.03) and sport (OR = 1.44 [1.04, 1.96], p = 0.02) were significant predictors of LLI in the previous 12 months. Conclusion Leg dominance may play a role in unilateral differences. LM thickness and LM CSA asymmetry were predictors of injury. Preseason screening of LM morphology and function could help identify athletes at risk of LBP and LLI. This could allow coaches, medical staff, and strength and conditioning staff to target these individuals and provide specific injury prevention programs.

Paraspinal Muscle Changes in Individuals with and without Chronic Low Back Pain over a 4-Month Period: A Longitudinal MRI Study

“…While our study did not separate left and right sides to compare muscle morphology and composition, it would be interesting to see if the smaller side of the ES at L5 had any correlation with the smaller side in the LM and PS. Previous research suggested that LM CSA % asymmetry at L5 was the best predictor of lower limb injury in athletes [ 24 ]. With increased asymmetry of the LM, one may expect the ES to be smaller on the contralateral side as a means of compensation to aid in stabilization of the spine on the affected side.…”