Does knowledge of seat design and whiplash injury mechanisms translate to understanding outcomes?

Review of whiplash injury mechanisms and effects of anti-whiplash systems including active head restraint (AHR) and Whiplash Protection System (WHIPS).

This article provides an overview of previous biomechanical and epidemiological studies of AHR and WHIPS and investigates whether seat design and biomechanical knowledge of proposed whiplash injury mechanisms translates to understanding outcomes of rear crash occupants.

In attempt to reduce whiplash injuries, some newer automobiles incorporate anti-whiplash systems such as AHR or WHIPS. During a rear crash, mechanically based systems activate by occupant momentum pressing into the seatback whereas electronically based systems activate using crash sensors and an electronic control unit linked to the head restraint.

To investigate the effects of AHR and WHIPS on occupant responses including head and neck loads and motions, biomechanical studies of simulated rear crashes have been performed using human volunteers, mathematical models, crash dummies, whole cadavers, and hybrid cadaveric/surrogate models. Epidemiological studies have evaluated the effects of AHR and WHIPS on reducing whiplash injury claims and lessening subjective complaints of neck pain after rear crashes. RESULTS.: Biomechanical studies indicate that AHR and WHIPS reduced the potential for some whiplash injuries but did not completely eliminate the injury risk. Epidemiological outcomes indicate reduced whiplash injury claims or subjective complaints of crash-related neck pain between 43 and 75% due to AHR and between 21% and 49% due to WHIPS as compared to conventional seats and head restraints.

Yielding energy-absorbing seats aim to reduce occupant loads and accelerations whereas AHRs aim to provide early head support to minimize head and neck motions. Continued objective biomechanical and epidemiological studies of anti-whiplash systems together with industry, governmental, and clinical initiatives will ultimately lead to reduced whiplash injuries through improved prevention strategies.