Affiliations: [a] Department of Biomedical Engineering, Seoul National University College of Medicine, Seoul, Korea | [b] Department of Rehabilitation Medicine, Seoul National University Boramae Medical Center, Seoul, Korea | [c] Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul, Korea | [d] Department of Mechanical and System Design Engineering, Hongik University, Seoul, Korea | [e] School of Architecture, Hongik University, Seoul, Korea | [f] Hyundai Motors Namyang R&D Division, Hwaseong-si, Korea
Correspondence:
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Corresponding author: Shi-Uk Lee, Department of Rehabilitation Medicine, Seoul National University Boramae Medical Center, 20, Boramae-ro 5-gil, Dongjak-gu, Seoul 07061, Korea. Tel.: +82 28702671; E-mail: shiuk.lee@gmail.com.
Abstract: BACKGROUND: Optimal seatback angles for automobile drivers’ seats have been investigated based on comfort and back muscle activities; however, radiology supported evidences are scarce. OBJECTIVE: The aim of this study was to evaluate optimal range of the seatback reclining regarding torso angles for an automobile driver’s seat to preserve lumbar lordosis. METHODS:Thirty-one healthy volunteers were recruited among five body type categories. Lateral lumbar spine X-rays were obtained for the neutral sitting posture without seatback (reference), and with reclining angles of 23∘ to 33∘ by 2∘ intervals. The Cobb angles for the L1-L4, L4-S1, and L1-S1 segments were measured. RESULTS: The Cobb angle for L4-S1 was nearest to the reference (18.74 ± 1.57∘, mean ± standard error mean) at reclining angles of 29∘ and 31∘ (14.51 ± 1.41∘ and 14.47 ± 1.43∘, respectively). The Cobb angle at L4-S1 between reclining angles of 27∘(12.02 ± 1.31∘) and 29∘ (14.51 ± 1.41∘) were significantly different (p< 0.001). Tall men showed relatively preserved lordosis angles at all reclining angles. Fat men and short women demonstrated prominent loss of lordosis with excessively kyphotic L1-L4 segment. CONCLUSIONS: Reclining angles of 29∘ to 31∘ revealed to be optimal for preserving lordosis at the L4-S1 segment. Individualized healthcare-related guideline for driver’s seat adjustment setting is necessary.
