Low Back And Lower Limb Muscle Performance In Male And Female Recreational Runners With Chronic Low Back Pain
Authors: Congcong Cai, MSc
J Orthop Sports Phys Ther, Epub 21 Apr 2015. doi:10.2519/jospt.2015.5460

Study Design
Controlled Laboratory Study; Cross-sectional.

Objective
To compare lumbar extensor muscle fatigability, lumbar muscle activation, and lower limb strength between male and female runners with chronic low back pain (LBP) and healthy runners.

Background
Little is known about muscle performance in runners with chronic LBP.

Methods
18 recreational runners with chronic LBP (9 males and 9 females; mean age = 27.8 years) and 18 healthy recreational runners (9 males and 9 females; mean age = 24.6 years) were recruited. The median frequency slopes for bilateral iliocostalis and longissimus were calculated from electromyographic signals captured during a 2-minute Sorenson Test. The thickness changes of the transversus abdominis and lumbar multifidus between resting and contraction were measured using an ultrasound scanner. Peak concentric torque of the bilateral hip extensors,hip abductors, and knee extensors were measured using an isokinetic dynamometer at 60˚/s. The average values for both sides were used for statistics analysis.

Results
When averaged across genders, peak knee extensor torque was 12.2% lower in the LBP group compared to the healthy group [mean difference (95% CI) = 0.29 (0.06-0.53) Nm/kg, p = .016]. Male runners with chronic LBP exhibited smaller lumbar multifidus thickness changes compared to healthy male runners [mean difference (95% CI) = 0.13 (0.01-0.25) cm, p = .033]. No other group differences were observed.

Conclusion
Runners with chronic LBP exhibited diminished knee extensor strength compared to healthy runners. Male runners with chronic LBP demonstrated additional deficits in lumbar multifidus activation.

Read More: http://www.jospt.org/doi/abs/10.2519/jospt.2015.5460