Recent studies have shown that restrained occupants over the age of 50 in frontal crashes have a higher risk of injury in the rear seat than in the front, and have hypothesized that the incorporation of technology such as belt pre-tensioning and force limiting preferentially in the front seat is at least partially responsible for this trend. This study investigates the potential benefits and trade-offs of seat belt pretensioners and force-limiters in the rear seat using a series of frontal impact sled tests at two speeds (48 km/h and 29 km/h DeltaV) with a buck representing the interior of the reat seat occupant compartment of a contemporary mid-sized sedan. Four different dummies were tested: the Hybrid III six year old (in a booster seat, H3 6YO), the Hybrid III 5(th) percentile female (H3 AF05), the Hybrid III 50(th) percentile male (H3 AM50), and the THOR-NT. The restraints consisted of either a standard three point belt, or a 3-point belt with a retractor pretensioner and a progressive force-limiter (FL+PT). Each test condition was repeated in triplicate. The FL+PT restraints (compared to the standard restraints) resulted in a significant (p < or = 0.05) decrease in peak internal chest deflection for each of the Hybrid III dummies at both test speeds (48 km/h: 29% decrease for H3 6YO, 38% decrease for H3 AF05, 30% decrease for H3 AM50), and for the THOR-NT at a DeltaV of 29 km/h. At 48 km/h, the FL+PT restraint qualitatively decreased the average peak internal chest deflection of the THOR-NT, however this decrease was not statistically significant (p=0.06). Furthermore, the FL+PT system allowed little or no increase in forward head excursion, and improved whole-body kinematics for all dummies by restricting pelvic excursion and slightly increasing torso pitch. The results suggest that the FL+PT system studied here may provide injury-reducing benefit to rear seat occupants in moderate to high severity frontal crashes, although more study is needed to evaluate these restraints in other crash scenarios.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3256765 | PMC |
Bioengineering (Basel)
January 2025
Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, MA 01609, USA.
Background: Functional electrical stimulation-assisted rowing (FES rowing) is a rehabilitation exercise used to prevent disuse osteoporosis, which is common in people with spinal cord injury (SCI). However, its effect on bone loss prevention varied in SCI patients, potentially due to inconsistent loading. This study investigates the effect of ergometer setup and rowing speed on lower extremity loading during rowing.
View Article and Find Full Text PDFTraffic Inj Prev
November 2024
ProBiomechanics LLC, Bloomfield Hills, Michigan.
Objective: This study compared kinematic and biomechanic responses of the 5 female Hybrid III in the right-rear and right-front passenger seats in frontal NCAP tests with 2015-16 MY vehicles. It focused on the lap-shoulder belt restraint of the rear passenger.
Methods: Eleven frontal NCAP tests were conducted by NHTSA at 56 km/h with a lap-shoulder belted 5 Hybrid III dummy in the right-rear and right-front seats.
Stapp Car Crash J
October 2024
Injury Biomechanics Research Center, The Ohio State University.
This study compared modern vehicle and booster geometries with relevant child anthropometries. Vehicle geometries (seat length, seat pan height, shoulder belt outlet height, and roof height) were obtained for 275 center and outboard rear seating positions of US vehicles (MY 2009-2022). Measurements of 85 US boosters (pan height and pan length) and anthropometries of 80 US children between 4-14yo (seated height, thigh length, leg length, and seated shoulder height) were also collected.
View Article and Find Full Text PDFAnn Biomed Eng
November 2024
Injury Biomechanics Research Center, The Ohio State University, 333 West 10th Ave, RM2063, Columbus, Ohio, 43210, USA.
In recent post-mortem human subjects (PMHS) studies in a high-speed rear-facing frontal impact (HSRFFI), the PMHS sustained multiple rib fractures. The seatback structure and properties of the seats might contribute to these fractures. This study aimed to determine if a homogeneous rear-facing seat with foam-covered seatback would mitigate the risk of thoracic injury during an HSRFFI.
View Article and Find Full Text PDFTraffic Inj Prev
November 2024
Department of Biomedical Engineering, Wake Forest University School of Medicine, Winston-Salem, North Carolina.
Objective: The objective of this study is to examine the effects of seatback angle, seat rotation, and impact speed on occupant kinematics and injury risk in highly automated vehicles.
Methods: The study utilized the Global Human Body Models Consortium midsize male (M50-OS+B) simplified occupant model in a simplified vehicle model (SVM) to simulate frontal crashes. The M50-OS+B model was gravity-settled and belted into the driver and left rear passenger seat.
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