Hides JA, Brown CT, Penfold L, & Stanton WR (2011). The Journal of Orthopaedic and Sports Physical Therapy, 41 (10), 767-75 PMID: 21891873
The transition from offseason to preseason training for many sports carries a substantial risk of thigh muscle strain injury (quadriceps, hamstrings, and adductors). Due to the contribution of the lumbopelvic region (core stability) to lower extremity function it is thought that the size and asymmetry of lumbopelvic stabilizers may play a role in these injuries. To assess this theory, Hides et al assessed the relationships between thigh muscle strain and lumbopelvic muscle (i.e., psoas major, quadratus lumborum, and multifidus muscles) size and asymmetry as well as transverse abdominis ability to contract and draw in the abdominal wall. Prior to the preseason training period 34 elite Australian football players had the cross-sectional area of each lumbopelvic muscle quantified with magnetic resonance imaging (47 players were initially screened but 13 were lost to follow-up). At the end of the 3 to 4 month training season 12 thigh muscle strains occurred: 2 hamstring strains, 4 quadriceps strains, and 6 adductor strains. Severity was determined by number of days lost of activity: 23 no injuries (0 days lost), 5 mild injuries (1 to 3 days lost), and 6 severe injuries (greater than 4 days lost). Mean cross-sectional areas of the multifidus muscles were significantly smaller among athletes with a severe thigh muscle strain compared to athletes with no injuries. Muscle size or asymmetry of the psoas major or quadratus lumborum, as well as ability to contract the transverse abdominis were not related to thigh muscle strain occurrence or asymmetry. Multifidus mean cross sectional area at L5 spinal level predicted severe thigh muscle strain with 96.4% specificity (correctly predicting a player not getting a severe strain) and 83.3% sensitivity (correctly predicting a severe strain).
This study provides further evidence that local stabilizing muscles of the lumbar spine may play a role in lower extremity injury. The multifidi are important stabilizers, sense lumbar spine position (because they are dense with muscle spindles), and hold lordosis; all of which has implications for pelvic position and thus functional implications for the musculature that attaches on the pelvis (e.g., quadriceps and hamstring). The lack of association between thigh muscle strains and the psoas major, transverse abdominis, and quadratus lumborum is thought to be due to several possible factors: 1) these muscles are less involved in lumbopelvic stability compared to the multifidus, 2) the ability to draw in the abdominal wall may not be relevant among elite athletes that can perform the task well, and 3) low sample size. The addition of measuring the multifidus cross-sectional area to current injury screening tools (physical exam, functional movement screening, landing kinematics) maybe a worthwhile venture for assessing injury risk. Ultrasound imaging could be an efficient method to do these measures since it is validated and maybe more accessible and cost effective to clinicians. This would allow us to target the often time consuming and clinician intensive interventions to improve multifidus activation to those with deficits (ultrasound imaging may even have a role as a biofeedback tool). Has anyone incorporated core training (or more specifically multifidus activation exercises) into their injury prevention programs? If so, what are your experiences with these interventions?
Written by: Dustin Grooms
Reviewed by: Jeffrey Driban, Jimmy Onate
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