Forces Recorded in Manual Therapy Techniques Applied to a Mannequin Simulating A 3- to 4-Month-Old Infant

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.

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.

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.

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.