Sitting posture influence on the biomechanical responses of the seated human body to whole-body vibration

Whole-body vibration (WBV) is widely used in rehabilitation, clinical practice and sports to improve various health conditions and enhance muscle performance. However, the biomechanical mechanisms underlying these beneficial effects remain unclear. Although vibration transmission during WBV training has been investigated in standing postures, seated postures remain largely unexplored. This study investigated how three sitting postures (slouched, upright, and tense) affect vibration transmission to and through the human body during WBV exposure. Twelve healthy male participants were exposed to vertical sinusoidal vibration with amplitude of 14.3 m/s 2 and frequency of 30 Hz while seated on a force plate mounted on the vibrating platform of a WBV training machine. Vertical and fore-and-aft head accelerations and interface forces between the body and the vibrating platform were measured. The tense posture produced significantly greater vertical and fore-and-aft head accelerations than the slouched and upright postures, indicating increased vibration transmissibility to the head with upper-body stiffening. In contrast, interface forces did not differ significantly among postures. It was concluded that sitting posture influences vibration transmission to the head during WBV exposure, whereas its effect on interface forces appears limited. A tense sitting posture increases head vibration transmissibility, emphasising the importance of posture when designing safe and effective WBV interventions.