Normative data on low back mobility and activity levels. Implications for neuromuscular reeducation

Area of Science:

• Biomechanics
• Kinesiology
• Neurophysiology

Background:

• Understanding normal low back mobility and muscle activation is crucial for diagnosing and treating back pain.
• Previous studies have explored sex and age-related differences in spinal motion and muscle function, but comprehensive data integrating both is limited.

Purpose of the Study:

• To establish baseline data for low back mobility and electromyographic (EMG) activity in a healthy population.
• To investigate potential sex and age interactions in spinal range of motion and trunk muscle activation during dynamic and static movements.
• To provide a comparison for future studies on patients with low back pain.

Main Methods:

• 121 healthy subjects were grouped by age and sex.
• Measurements included range of motion (straight leg raising, trunk rotation, lateral bending, forward flexion) and electromyography (EMG) of the erector spinae muscles.
• Dynamic (flexion-extension, rotation, stooping) and static (sitting) movements were assessed over a 10-second interval using EMG biofeedback.

Main Results:

• Women exhibited greater range of motion in straight leg raising, trunk rotation, and lateral bending; men showed greater forward flexion.
• A significant sex-age interaction was found only for lateral bending.
• EMG data confirmed the erector spinae's role in trunk extension, with greater unilateral activity during rotation. EMG activity ceased during full trunk flexion.
• Sex-age interactions were observed in all dynamic movements but not static activities.

Conclusions:

• Low back mobility and EMG patterns during dynamic movements show significant sex differences, precluding combined analysis across sexes within age groups.
• Static movements demonstrated less pronounced sex-age interactions.
• The established baseline data can inform clinical comparisons for low back pain patients.
• EMG biofeedback during dynamic lower back movements may offer a therapeutic approach for pain management by potentially improving posture.