November 2015

Greater Resting Lumbar Extensor Myofascial Stiffness in Younger Ankylosing Spondylitis Patients Than Age-Comparable Healthy Volunteers Quantified by MyotonPRO

Authors: B. J. Andonian, A. T. Masi, J. C. Aldag, A. J. Barry, B. A. Coates, K. Emrich, J. Henderson, J. Kelly, K. Nair

Affiliations: Department of Medicine, University of Illinois College of Medicine, Peoria, IL; Bradley University, Peoria, IL; Department of Mechanical Engineering, Bradley University, Peoria, IL; Department of Physical Therapy, Bradley University, Peoria, IL, USA

Journal: Archives of Physical Medicine and Rehabilitation - November 2015, Volume 96, Issue 11, Pages 2041-2047 (DOI: 10.1016/j.apmr.2015.07.014)

Objective: To quantify resting lumbar erector myofascial stiffness in younger patients with ankylosing spondylitis (AS) and age-comparable healthy control subjects using a handheld mechanical impulse-based myotonometric device.

Design: A case-control study of 24 patients with AS and 24 age-comparable healthy control subjects.

Setting: University physical therapy department.

Participants: Patients with AS (men: n=19; women: n=5; total: N=24) and healthy volunteers (men: n=19; women: n=5; total: N=24) without low back pain (age range, 18–46y).

Interventions: Not applicable.

Main Outcome Measure: Lumbar myofascial stiffness.

Results: At the initial measurements, median stiffness (Nm) of the averaged right- and left-sided values was greater (P=.021) in 24 patients with AS than 24 control subjects (268.9 vs 238.9, respectively). Repeated measurements after a 10-minute prone resting period were also greater (P=.007) in patients with AS than control subjects (281.0 vs 241.4, respectively). The 48 averaged right- and left-sided values from baseline and 10-minute measurements were compared in each subject group. The patients with AS more frequently (P=.012) had stiffness values >250Nm (35 [72.9%] vs 22 [45.8%] in control subjects).


Keywords: Back muscles, Muscle tonus, Rehabilitation, Spondylitis, ankylosing

Lumbar myofascial stiffness was greater in 24 patients with AS than in the control subjects. A hypothesized biomechanical concept of increased resting lumbar myofascial stiffness in AS may be supported by this preliminary controlled study.