Establishing a protocol for the measurement of human exposure to foot-transmitted vibration
Date
2018-03-27
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Abstract
Foot-transmitted vibration (FTV) is defined as vibration exposure where the primary route of
vibration transmission is through the feet. Individuals can be exposed to FTV through a vibrating
platform that they stand on or from vibrating foot-operated controls. Workers exposed to FTV
are at risk of suffering from vibration white-foot, an irreversible disease with vascular,
neurological and musculoskeletal symptoms. In order to understand injury risk, the transmission
of vibration from a vibrating surface into the foot can be measured. The international standards
for the measurement of occupational vibration exposure (ISO 2631-1, 1997; ISO 5349-1, 2001)
do not provide appropriate guidance for FTV exposure measurement. Although several
researchers have reported worker exposure to FTV, the reliabilities of the methods used to
measure FTV have yet to be studied.
The purpose of this thesis is to propose a reliable protocol for the measurement of FTV exposure
(Vance FTV Measurement Protocol, V-FTVMP). Preliminary testing was conducted to examine
how factors such as location of accelerometer placement on the foot, changes in standing
posture, time of day that measurements are taken, and duration of measurement, influence
measures of FTV exposure. These findings were translated into the V-FTVMP. Inter-rater and
intra-rater reliability of the proposed method for the measurement of FTV transmissibility were
determined by testing the protocol with three raters and 12 participants. Transmissibility was
measured at the toe as the ratio of vibration input (measured on the platform) to vibration output
(measured on the surface of the toe), with values over one indicative of vibration amplification
and less than one indicative of attenuation. Transmissibility was also calculated as a ratio at the
ankle with input measured at the platform and output measured from the medial malleolus of the
iv
ankle. Mean un-weighted root-mean-squared (r.m.s.) accelerations (z-axis) for all accelerometer
locations were calculated for all participants and found to be 13.01 m/s2
(±0.87), 12.68 m/s2
(±1.19), 8.23 m/s2
(±2.24), and 16.05 m/s2
(±3.81) for measures at the platform at the toe,
platform at the ankle, toe at the first metatarsal head and ankle at the medial malleolus,
respectively. The mean transmissibility for all participants was measured as 0.63 (±0.16) at the
toe, and 1.27 (±0.30) at the ankle. The intraclass correlation tests showed good or acceptable
reliability for all locations: platform location at the toe ICC =.83 (CI =.67 -.92), platform at ankle
ICC =.82 (CI=.65-.92), toe ICC =.77 (CI =.37 -.81), ankle ICC =.60 (CI =.18 -.68). Based on the
results of this study, it appears the V-FTVMP can generate reliable measures of FTV. Additional
research led by independent groups is needed to confirm these results and to further validate the
protocol.
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Keywords
Vibration, standardization, standing, reliability, validation, measurement protocol