• Keil BG
• Fludder CJ

• Biomechanical Phenomena
• Infant
• Manikins
• Musculoskeletal Manipulations

Objective: The purpose of this study was to record preload force, peak force, and time from preload to peak force used with 4 manipulation techniques in a simulated 3- to 4-month-old infant.

Methods: The project recorded 4 scenarios involving spinal manipulation applied to a mannequin comparable with a 3- to 4-month-old infant by 2 postgraduate trained and experienced practitioners and educators in pediatric spinal manipulation and mobilization. Results for preload force, peak force, time to peak, and rate of force application were determined.

Results: Preload force was less than 10 N in the majority of scenarios. Average peak force in 3 cervical spine scenarios ranged from 35.2 to 79.9 N. Sacral data recorded an average peak force of 34.9 to 41.2 N with a standard distribution of 3.6 to 7.1 N. The time to peak force recorded for the 4 scenarios were under 110 ms. The rate of force production for all but 1 scenario was in excess of 300 N/s. Intrapractitioner data analysis demonstrated peak forces were not significantly different across 3 scenarios, with interpractitioner data not significantly different across 2 scenarios.

Conclusion: Average peak forces recorded were similar to those previously reported. Time to peak recordings were typically under 100 ms and rate of force application above 300 N/s; within the optimal range for muscle spindle receptor and Golgi tendon organ activation. Further research into forces used across the pediatric age ranges is needed.

Author keywords: Biomechanics; Chiropractic; Infant; Manual Therapies

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