• Pagé I
• Biner É
• Descarreaux M

• Affiliation / Université du Québec à Trois-Rivières (UQTR). Département d'anatomie
• Affiliation / Université du Québec à Trois-Rivières (UQTR). Département de chiropratique
• Affiliation / Université du Québec à Trois-Rivières (UQTR). Département des sciences de l'activités physique
• Affiliation(G) / Canada / Quebec / Trois-Rivières
• Back Muscles / physiology
• Electromyography
• Manipulation, Spinal
• Mobilization
• Musculoskeletal Manipulations
• Thoracic Vertebrae / physiology

OBJECTIVE: The purpose of this study was to compare vertebral displacements (absolute and relative) and muscle responses induced by spinal manipulative therapy of short (spinal manipulation) and long (spinal mobilization) impulse duration.

METHODS: Twenty-five healthy adults (without thoracic pain) were recruited for this crossover study. Six spinal manipulative therapies (255 N peak force) of different impulse durations (100, 125, 200, 500, 1000, and 1500 ms) were delivered to each participant's T7 transverse process using a mechanical device. Impulse duration effect on the vertebral displacement (absolute displacement of T6, T7, and T8 and relative displacement between T7 and T6 and between T7 and T8) and the thoracic muscle response (surface electromyography) were assessed using mixed-model analyses of variance and predefined linear trend analyses.

RESULTS: Results showed a linear increase in the absolute vertebral displacement for T8 (P = .002) and a linear decrease in the T7/T6 and T7/T8 relative displacement (P < .0001) when impulse duration was increased. The data of 24 participants were available for electromyography analysis. A significant main effect of impulse duration on surface electromyography response was observed (P < .0001, ƞ_p²=0.43). Planned comparisons for a linear trend between these variables revealed a negative relationship (P < .0001). Only 13 of the 24 participants with available data presented a muscle response at every impulse duration.

CONCLUSION: These results support the assumption that spinal manipulation and spinal mobilization might operate under distinct mechanisms.

Author keywords: Manipulation, Spinal; Musculoskeletal Manipulations; Electromyography; Biomechanical Phenomena

Author affiliations: IP: Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada; EB: Department of Chiropractic, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada; MD: Department of Human Kinetics, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada

This abstract is reproduced with the permission of the publisher; full text is available by subscription. Click on the above link and select a publisher from PubMed's LinkOut feature.