Mechanisms of Specific Trunk Exercises in Low Back Pain

The research objective is to determine which physical therapy (PT) treatment is the most efficacious for patients with lower back pain (LBP), who have been subgrouped based on certain clinical features. There is only limited evidence that supports any one PT treatment for patients with LBP since PT treatment outcomes for exercise protocols are equivocal, given the heterogeneous clinical features of patients with LBP. Thus, classification of patients with LBP into subgroups with shared clinical features has been identified as a research priority by several groups in order to prescribe the most efficacious PT treatment for each homogeneous subgroup. The investigators hypothesize that particular PT treatments are most efficacious when applied to patients with LBP, who present with particular clinical and neuromuscular features.

The proposed studies focus on 2 schemas to classify LBP: 1) the Treatment-Based Classification (TBC) system, from which clinical prediction rules about who is most likely to benefit from spinal stabilization exercises (among others) have been developed, and 2) the Movement System Impairment-Based Classification (MSI) system, which includes 5 classifications of LBP named for the specific direction(s) of movements and alignments associated with the person's LBP.

The primary purpose of this proposal is to conduct a prospective, randomized, controlled Phase II clinical trial in order to examine whether or not treatment matched to a patient's specific signs and symptoms (patient-matched) per the TBC is more effective than the MSI system for improving short- (6 weeks) and long-term (12 and 24 months) outcomes in people with chronic LBP. A secondary purpose is to identify prognostic factors that predict clinical outcomes in the 2 treatment groups being compared.

Subjects will be assigned to one of two study arms:

1. eligible for Treatment-Based Classification (TBC) stabilization exercises based on current criteria ('Eligible' Subject Group); and
2. subjects who are not eligible for the TBC-based stabilization exercises ('Ineligible' Subject Group).

Within in each study arm, subjects will be randomly assigned to 1 of 2 exercise protocols for a 6-week period:

1. stabilization - a protocol focused on improving the motor control of trunk muscles to stabilize the spine; or
2. MSI-based - a classification-specific treatment focused on education and instruction for modifying movement strategies during functional activities, and on exercises specific to the classification category.

Laboratory measures (muscle activation, kinematics, forces) during standardized tasks will quantify neuromuscular impairments associated with LBP and clinical questionnaires will quantify changes in pain, function, and health status pre- and post-treatment. The addition of neuromuscular measures to these classification schemas could improve the sensitivity and specificity of each.

Eligibility Criteria:
Inclusion Criteria:

* a history of chronic LBP with or without recurrences for a minimum of 12 months;
* between 21 - 55 years of age;
* able to stand and walk without assistance;
* have an Oswestry Disability Score of 19% or higher AND/OR less than an 8 on one activity reported on the Patient Specific Functional Scale,

Exclusion Criteria:

* any major structural spinal deformity including scoliosis, kyphosis, or stenosis;
* spinal fracture or dislocation;
* osteoporosis;
* ankylosing spondylitis;
* rheumatoid arthritis;
* disc herniation with corroborating clinical signs and symptoms;
* serious spinal complications such as tumor or infection;
* previous spinal surgery;
* frank neurological loss, i.e., weakness and sensory loss;
* pain or paresthesia below the knee;
* etiology of LBP other than the lumbar spine, e.g., hip joint;
* history of neurological disease which required hospitalization;
* active treatment for cancer;
* history of unresolved cancer;
* pregnancy or less than 6 months post-partum or less than 6 months post weaning;
* magnified symptom-behavior;
* worker's compensation or disability case;
* in litigation for the LBP problem;
* have a BMI ≥ 30.