The Forgotten Role of Back Muscle Characteristics to Tailor Exercise Therapy for Recurrent Non-specific Low Back Pain

Back to Back: the Forgotten Role of Back Muscle Characteristics to Tailor Exercise Therapy for Recurrent Non-specific Low Back Pain

Patients with non-specific low back pain will be compared to healthy, age- and sex-matched controls to determine the most discriminating back muscle characteristics and to delineate possible phenotypes of patients with non-specific low back pain showing impaired proprioceptive postural control. Additionally, the group of patients with non-specific low back pain will receive a 16-week, high-load proprioceptive training program. The effects of this training program on the different back muscle characteristics and proprioceptive postural control will be evaluated.

The Back-to-Back study consists of a cross-sectional study and a proof-of-concept study. The cross-sectional study aims to gain more insight into the peripheral underlying mechanisms of impaired proprioceptive postural control in patients with non-specific low back pain. Macroscopic, microscopic, hemodynamic, and electrophysiological characteristics of the lumbar multifidus and erector spinae muscles will be compared between patients with non-specific low back pain and healthy, age- and sex-matched controls. The interrelatedness between these back muscle characteristics and the correlation with proprioceptive postural control will be examined. The most discriminating muscle characteristics will be determined based upon which phenotypes of patients with non-specific low back pain will be delineated. The proof-of-concept study aims to assess the effects of high-load proprioceptive training on back muscle characteristics and proprioceptive postural control in patients with non-specific low back pain.

Inclusion Criteria:

Patients with non-specific low back pain:

• Aged 18-60 years
• Non-specific low back pain without radicular leg pain
• Mechanical low back pain with episodes of <4 on the numerical pain rating scale and episodes of >6 on the numerical pain rating scale
• Non-specific low back pain for three months or more
• Score of 20% or more on the Modified Low Back Pain Disability Questionnaire
• Informed consent to participate

Healthy controls:

• Aged 18-60 years
• No history of low back pain needing medical treatment or resulting in a limited activity level
• No low back pain in the previous six months
• Informed consent to participate

Exclusion Criteria:

• Pregnancy
• Previous trauma or surgery to the spine, pelvis or lower limbs
• Structural spinal deformity (e.g., scoliosis)
• Neurological, neuromuscular, respiratory or systemic disease
• Central sensitization: score of 50/100 or more on the Central Sensitization Inventory
• Specific vestibular or balance problems
• Acute lower limb or neck problems
• Body mass index of 30 kg/m² or more