Poor back muscle endurance is related to pain catastrophizing in patients with chronic low back pain.

Study Design: An experimental and comparative study of chronic low back pain (CLBP) patients and healthy controls.

Objective: To use a motivation-independent electromyography (EMG) based test of back muscle capacity to determine whether back muscle deconditioning is present in CLBP patients and whether it is related to pain-related psychological variables.

Summary Of Background Data: The verification of the deconditioning syndrome in CLBP patients might be biased by the use of performance-based measures to assess physical fitness, especially in patients having fear of injury.

Specificity of a back muscle roman chair exercise in healthy and back pain subjects.

Purpose: Roman chair exercises are popular for improving back muscle endurance but do not specifically target back muscles. This study aimed to determine whether an adaptation of the Roman chair exercise would induce more fatigue in back muscles than in hip extensors.

Methods: For this study, 16 healthy subjects and 18 patients with nonspecific chronic low back pain performed trunk flexion-extension cycles until exhaustion in a Roman chair with hips flexed at 40°.

The effect of sex and chronic low back pain on back muscle reflex responses.

Different back muscle reflex assessment protocols have shown abnormally longer reflex latency responses of back muscles in chronic low back pain (CLBP). However, many confounding variables are difficult to control, such as the load magnitude and the preactivation of trunk muscles. The aims of this study were to evaluate, in 30 subjects with CLBP and 30 healthy controls, the activation levels of back muscles during pre-loading and their reflex responses to sudden loading.

Specificity of a back muscle exercise machine in healthy and low back pain subjects.

Purpose: To determine whether dynamic back muscle endurance exercises in a semisitting position induce more fatigue in back muscles than that in hip extensors in healthy controls as well as in patients with nonspecific chronic low back pain.

Methods: Sixteen healthy volunteers and 18 volunteers with nonspecific chronic low back pain performed trunk flexion-extension cycles until exhaustion at 60% of their strength in a machine designed for back exercise in a semisitting position with knees' angle at 135 degrees . The number of cycles and perceived muscle fatigue (Borg CR-10 scale) at five areas (upper and lower back, gluteus, hamstrings, and quadriceps) were used as fatigue criteria.

Electromyographic assessment of back muscle weakness and muscle composition: reliability and validity issues.

Objective: To assess the reliability and construct validity of various electromyographic indices developed to assess back muscle weakness and muscle fiber composition.

Design: A prospective study with repeated measures performed on 3 days along with comparisons of groups presenting different back strength and/or back muscle fiber composition.

Setting: A biomechanics laboratory within a rehabilitation center.