Sports Medicine Research: In the Lab & In the Field: It’s Only One Little Muscle Group…The Impact of Lumbar Multifidus Size on Lower Extremity Injury (Sports Med Res)


Monday, July 21, 2014

It’s Only One Little Muscle Group…The Impact of Lumbar Multifidus Size on Lower Extremity Injury

Small Multifidus Size Predicts Football Injuries.

Hides JA, Stanton WR, Mendis MD, Franettovich MM, and Sexton MJ. Orthopaedic Journal of Sports Medicine June 2014 2: 2325967114537588, first published on June 16, 2014 doi:10.1177/2325967114537588

Take Home Message: Smaller lumbar multifidus size during preseason and the competitive season was associated with lower extremity injury in Australian Football. Additionally, lumbar multifidus asymmetry, limb kicking dominance and a history of low back pain were also associated with increased lower extremity injury.

Musculoskeletal injuries to the lower extremity are common during preseason and in-season competitions. If we could identify modifiable factors associated with these injuries then it may allow us to develop injury prevention programs. Stabilizing muscles of the lumbo-pelvic region may contribute to lower extremity injury risk but this needs to be verified in larger studies across both preseason and competitive seasons. The authors assessed ~260 Australian Football League players to determine whether the size, asymmetry, and ability to contract the lumbar multifidus were related to new lower extremity injuries during preseason and competitive season. They also attempted to establish combinations of factors to best predict injury. Participants from six Australian Football League teams provided demographic and sport history details and received ultrasound imaging of the lumbar multifidus at the start of both preseason and competitive seasons. Bilateral cross-sectional area (CSA), and muscle thickness at rest and during voluntary isometric contraction were recorded for all individuals along with histories of injury and low back pain. The team medical staff diagnosed injuries during the preseason or playing season as any sport-related injury that prevented a player from completing a practice or game. Lower extremity injury occurred in 38% (105 athletes) and 70% (191 athletes) athletes during the preseason and competitive seasons, respectively. The authors found that an athlete with a smaller lumbar multifidus CSA is more likely to have a lower extremity injury during the preseason and competitive season. Furthermore, an athlete with a smaller muscle thickness on the preferred kicking leg compared with the opposite limb was more likely to suffer a lower extremity injury. The authors identified two key injury prediction models: 1) decreased lumbar multifidus CSA, and history of low back pain increased the risk of lower extremity injuries during the preseason; and 2) decreased CSA, changes in lumbar multifidus size, and kicking limb were associated with lower extremity injuries during the competitive season. Athletes with a preferred kicking limb and reduced lumbar multifidus sizes were at increased risk for injury, while those who use both limbs equally and increased muscle size had a decreased risk of lower extremity injury. The two models identified 61% and 92% of the athletes that sustained an injury in the preseason and competitive season respectively, while identifying 85% and 46% of those that did not sustain an injury.

These findings may indicate that increased lumbar multifidus size and symmetry may reduce the risk of lower extremity injury during preseason training and the competitive season. Interestingly, the ability to maintain lumbar multifidus size throughout the season or increase size following an injury reduced the risk of lower extremity injury across the competitive season. A smaller lumbar multifidus may indicate reduced neuromuscular control, which could  lead to instability and improper transferring of forces between the lower extremity and spine. Specific lumbar multifidus training throughout the offseason and regular season may reduce the number of lower extremity injuries sustained by athletes during competition. However, the current study only identified a relationship between lumbar multifidus size and lower extremity injury and does not indicate causality between the two variables. Additional research should focus on lumbar multifidus exercise training programs and lower extremity injury prevention. The current findings support the incorporation of lumbar multifidus exercise as part of an injury prevention program since the risk associated with exercise training in minimal.

Questions for Discussion: Why do you think limb dominance and bilateral muscle imbalance influence injury in sports that require bilateral limb skill contributions? Do you assess lumbar multifidus size and muscle function? Do you do prevention exercises that target the multifidus with your athletes?

Written by: Mark A. Sutherlin
Reviewed by: Jeffrey Driban

Related Post:

Recommended Readings:
Hides JA and Stanton WR. Can motor control training lower the risk of injury for professional football players? Med Sci Sports Exerc. 2014;46(4):762-8. doi:10.1249/MSS.0000000000000169.

Hides, J., Stanton, W., Mendis, M., Franettovich Smith, M., & Sexton, M. (2014). Small Multifidus Muscle Size Predicts Football Injuries Orthopaedic Journal of Sports Medicine, 2 (6) DOI: 10.1177/2325967114537588


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