Equal sensation curves for whole-body vibration expressed as a function of driving force

Previous studies have shown that the seated human is most sensitive to wholebody vertical vibration at about 5 Hz. Similarly, the body shows an apparent mass resonance at about 5 Hz. Considering these similarities between the biomechanical and subjective responses, it was hypothesised that, at low frequencies, subjective ratings of whole-body vibration might be directly proportional to the driving force. Twelve male subjects participated in a laboratory experiment where subjects sat on a rigid seat mounted on a shaker. The magnitude of a test stimulus was adjusted such that the subjective intensity could be matched to a reference stimulus, using a modified Bruceton test protocol. The sinusoidal reference stimulus was 8 Hz vibration with a magnitude of 0.5 m/s² r.m.s. (or 0.25 m/s² r.m.s. for the 1 Hz test); the sinusoidal test stimuli had frequencies of 1, 2, 4, 16 and 32 Hz. Equal sensation contours in terms of seat acceleration showed data similar to those in the literature. Equal sensation contours in terms of force showed a nominally linear response at 1, 2 and 4 Hz but an increasing sensitivity at higher frequencies. This is in agreement with a model derived from published subjective and objective fitted data

A Review of Factors Influencing Whole-Body Vibration Injuries in Forestry Mobile Machine Operators

Mobile machine operators in the forestry industry are subjected to long hours of whole-body vibration exposure while adopting static seated postures and performing repeated hand and foot movements to operate controls. These conditions have been found to put operators at increased risk for musculo-skeletal injuries and pain in the neck, shoulders, and back, as well as decreased productivity. This paper provides a review of the individual risk factors for these musculoskeletal problems and explores the possible interactions between risk factors and their effects on injury and productivity. Gaps in the literature and directions for future research are identified and discussed

Whole-body vibration and occupational physical performance: a review

© 2015 Springer-Verlag Berlin Heidelberg Introduction: In the occupational environment, there are a considerable number of stressors that can affect physical performance in job tasks. Whole-body vibration (WBV), which arises from vehicle transit, is one such stressor that has been demonstrated to alter human function in several ways. This study identifies the known physical changes to human function which result from WBV, to comment on changes which may translate to performance in physically demanding occupational tasks. Methods: A systematic review is performed on the literature relating to changes in the neuromuscular, physiological and biomechanical properties of the human body, when exposed to WBV. Selection criteria are constructed to synthesise articles which strictly relate to in-vehicle WBV and physical responses. Results: In total, 29 articles were identified which satisfied the criteria for inclusion. A range of physical responses produced from WBV are presented; however, little consistency exists in study design and the responses reported. Discussion: Given the inconsistency in the reported responses, the precise changes to human function remain unknown. However, there is sufficient evidence to warrant the design of studies which investigate occupationally relevant physical performance changes following WBV