Trunk muscle recruitment patterns in simulated precrash events

Area of Science:

• Biomechanics
• Human Factors Engineering
• Automotive Safety

Background:

• Understanding occupant responses during precrash events is crucial for developing effective safety systems.
• Active human body models require accurate data on trunk muscle recruitment patterns.

Purpose of the Study:

• To quantify trunk muscle activation during multi-directional whole-body accelerations simulating precrash events.
• To identify trunk muscle recruitment patterns for active human body model development.

Main Methods:

• Four subjects underwent sled-based accelerations (0.55g) in 8 directions.
• Electromyographic (EMG) activity of four trunk muscles (rectus abdominis, internal oblique, iliocostalis, multifidus) was measured.
• EMG data were normalized to maximum voluntary contraction (MVC) and analyzed at 150, 300, and 600 ms.

Main Results:

• Trunk muscle EMG activity generally remained below 40% MVC.
• Highest EMG amplitudes were observed during leftward and left rearward perturbations at 150 and 300 ms.
• Anterior muscle activity decreased by 600 ms, while posterior muscle activity persisted.

Conclusions:

• Preliminary findings suggest directional tuning of trunk muscle activity during simulated precrash accelerations.
• Further studies with more subjects are needed.
• These data support the development of trunk muscle recruitment strategies in active human body models for precrash scenario prediction.