ABSTRACT
This study explores the dose response between whole-body vibration (WBV) exposure and musculoskeletal complaints among mail carriers riding motorcycles for postal delivery. A questionnaire survey was performed and, then, daily exposure was determined. Questionnaire results indicate that male mail carriers (n= 1 03, average 39.9±7.8 years) have a higher subjective pain than male back-office staff (n=34, average 49.5±5.1 years) in the post office at all investigated body regions. Twenty-five mail carriers (average 39.1±6.5 years) were recruited for determining the daily WBV exposures from carriers participating in the questionnaire survey. Only one mail carrier had a vibration dose value (VDV) exceeding the 17 mls2 boundary, indicating a high probability of adverse health, as specified by ISO 26311 (1997) guidelines. However, 13 of the 25 evaluated mail carriers had Sed exceeding the 0.8 MPa boundary, indicating a high probability of adverse health, as specified by lSO 2631-5 (2004) guidelines. Analytical results demonstrate that these mail carriers have experienced WBV containing high shocks. By integrating analytical results derived from a questionnaire survey and daily exposure measurements, we believe that a dose-response relationship may exist between
Keywords: Motorbike, Postman, Musculoskeletal Complaint, ISO 2631
Previous studics indicatc that driver vibration exposurc dcpends on road or traffic conditions, vehicle characteristics such as speed, typc, weight, seat, maintenance and engine sizc, and drivcr characteristics such as age, characteristics, cxperience, sitting posturc, and body wcight (Peitte and Malehaire, 1992; Ozkaya el al.,1994; Malehaire el al., 1996; Donati, 1998; Chen et al., 2003; Mansficld and Griffin, 2002). Commonly reported health effects caused by whole-body vibration (WBV) exposure include discomfort, musculoskeletal problems, muscular fatigue, reduced stability, and altered vestibular function (Seidel, 1993; Wasserman et al., 1997; Bongers et at., 1988; Griffin, 1998). Several studies have also indicated that longterm WBV exposure is associated with early spinal degeneration (Frymoyer et al. 1984), low back pain, and herniated lumbar disc (Bovenzi and Zadini 1992, Boshuizen et al. 1992).
