Pre‐crash occupant motion has the potential to influence restraint performance, particularly for children. We examined kinematics of adults versus children in a vehicle subjected to a constant radius manoeuvre designed to produce sustained lateral acceleration via closed‐course testing. Nine adults and six children were seated in the right rear seat of a late‐model year 4‐door sedan. A constant radius manoeuvre was conducted with an average lateral acceleration of ~0.5 g for ~30 seconds.

Vehicle dynamics were measured with an Inertial and GPS Navigation system. Head and trunk displacement were collected with an eight‐camera 3D motion capture system. Electromyography sensors were placed on the upper body and lower limbs and load cells were placed on the seat belt to characterise bracing behaviours. Head and trunk displacement and their variability were compared between age groups. Results showed that in the first four seconds of the manoeuvre, children had less head and trunk lateral displacement than adults even when data were normalised by seated height. Neck muscle activation was greater in children compared to adults. These findings suggest children may brace more and with a different neuromuscular strategy than adults to control motion.