Kinematic analysis for determination of bioequivalence of a modified Hybrid III test dummy and a wheelchair user.

We investigated whether a modified 50th-percentile Hybrid III test dummy (HTD) (First Technology Safety Systems, Plymouth, MI) would have motion similar to a wheelchair test pilot (TP) with T8 paraplegia. Test cases were seated in a Quickie P100 electrically powered wheelchair (Sunrise Medical, Inc., Phoenix, AZ) driven at three speeds (0.8, 1.4, and 2.0 m/s). Three braking conditions-joystick release, joystick full reverse, and emergency power-off-were used to stop the wheelchair. The subsequent upper-body motion was recorded for the creation of kinematic exposure profiles of the wheelchair riders. The maximum concentration (Cmax) and area under the trunk angular displacement, velocity, and acceleration curves (AUC0-Cmax) were calculated. Assessments of average, individual, and population bioequivalence were conducted after data were subjected to natural logarithmic transforms. Only the Cmax of the trunk angular acceleration of the HTD and TP was average bioequivalent (0.82-1.04). Both Cmax and AUC0-Cmax measures for all kinematic exposures between the TP and HTD were individual and population bioequivalent (95% upper-confidence bound < 0, linearized bioequivalence criteria). This indicates that the HTD is a suitable surrogate for a wheelchair user in low-speed, low-impact wheelchair studies.