OBJECTIVES: The purpose of this study was to investigate the effects of pre-impact bracing on the chest compression, reaction forces, and accelerations experienced by @entity1 occupants during low-speed frontal sled tests. METHODS: A total of twenty low-speed frontal sled tests, ten low severity (   2.5g, /\v = 5kph) and ten medium severity (   5g, /\v = 10kph), were performed on five 50(th)-percentile male @entity1 volunteers. Each volunteer was exposed to two impulses at each severity, one relaxed and the other braced prior to the impulse. A 59-channel chestband, aligned at the nipple line, was used to quantify the chest contour and anterior-posterior sternum deflection. Three- @entity2270 accelerometer cubes were attached to the sternum, 7(th) cervical vertebra, and sacrum of each subject. In addition, three linear accelerometers and a three- @entity2270 angular rate sensor were mounted to a metal mouthpiece worn by each subject. Seatbelt tension load cells were attached to the retractor, shoulder, and @entity3813 portions of the standard three-point driver-side seatbelt. In addition, multi- @entity2270 load cells were mounted to each interface between the subject and the test buck to quantify reaction forces. RESULTS: For relaxed tests, the higher test severity resulted in significantly larger peak values for all resultant accelerations, all belt forces, and three resultant reaction forces (right foot, seatpan, and seatback). For braced tests, the higher test severity resulted in significantly larger peak values for all resultant accelerations, and two resultant reaction forces (right foot and seatpan). Bracing did not have a significant effect on the occupant accelerations during the low severity tests, but did result in a significant decrease in peak resultant sacrum linear acceleration during the medium severity tests. Bracing was also found to significantly reduce peak shoulder and retractor belt forces for both test severities, and peak @entity3813 belt force for the medium test severity. In contrast, bracing resulted in a significant increase in the peak resultant reaction force for the right foot and steering column at both test severities. Chest compression due to belt loading was observed for all relaxed subjects at both test severities, and was found to increase significantly with increasing severity. Conversely, chest compression due to belt loading was essentially eliminated during the braced tests for all but one subject, who sustained minor chest compression due to belt loading during the medium severity braced test. CONCLUSIONS: Overall, the data from this study illustrate that muscle activation has a significant effect on the biomechanical response of @entity1 occupants in low-speed frontal impacts.

XXXX occupants in low-speed frontal sled tests: effects of pre-impact bracing on chest compression, reaction forces, and subject acceleration.

@entity1 :: ('9606', 'Species') :: ['human'] @entity2270 :: ('MESH:C566610', 'Disease') :: ['axis'] @entity3813 :: ('7939', 'Gene') :: ['lap']
@entity1 :: (9606,Species) :: ['Human']
