Quantification of lumbar stability by using 2 different abdominal activation strategies

Area of Science:

• Biomechanics
• Human Movement Science
• Spinal Stabilization

Background:

• The abdominal hollowing technique is often promoted for lumbar spine stabilization.
• The effectiveness of abdominal hollowing versus full abdominal cocontraction for stability is not well-established.

Purpose of the Study:

• To compare the efficacy of the abdominal hollowing technique against full abdominal muscle cocontraction (bracing) for lumbar spine stabilization.
• To investigate the mechanical contribution of the transversus abdominis muscle during abdominal hollowing.

Main Methods:

• A within-subject, repeated-measures design was employed in a laboratory setting.
• Eight healthy males performed abdominal bracing and hollowing exercises under various loading conditions (bilateral and asymmetric).
• Electromyography and spine kinematics were recorded, and spine stability index and lumbar compression were calculated. A simulation assessed isolated transversus abdominis activation.

Main Results:

• The abdominal bracing technique improved stability by 32% and increased lumbar compression by 15% in a simulated ideal case.
• Isolated activation of the transversus abdominis contributed minimally to stability (0.14%) with a negligible decrease in compression (<0.1%).

Conclusions:

• The abdominal bracing technique demonstrates superior mechanical effectiveness for enhancing lumbar spine stability compared to abdominal hollowing.
• There is no significant mechanical rationale for using the abdominal hollow or isolated transversus abdominis activation to improve spinal stability.