Effect of Phase on Human Responses to Vertical Whole-Body Vibration and Shock—analytical Investigation

Matsumoto, Yasunao; Griffin, Michael J.

doi:10.1006/jsvi.2001.3975

Cited by 9 publications

(4 citation statements)

References 15 publications

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“…The first peak in the ground reaction force data can be considered a shock input. A shock can be represented by a half sine acceleration (Matsumoto and Griffin, 2002). An effective input frequency, f i , was estimated, using the time interval from the time of the maximal loading rate to the time of the impact peak as a quarter of a whole oscillation.…”

Section: Discussionmentioning

confidence: 99%

Muscle activity in the leg is tuned in response to impact force characteristics

Boyer

Nigg

2004

Journal of Biomechanics

113

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Section: Discussionmentioning

confidence: 99%

Muscle activity in the leg is tuned in response to impact force characteristics

Boyer

Nigg

2004

Journal of Biomechanics

113

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“…Recent studies have attempted to categorize the possible mechanisms of injury related to WBV [6][7][8][9][10][11] and develop models that could optimize preventive measures [12][13][14][15]. Although none of these investigators addresses the effects of WBV on wheelchair users, their conclusions may be used to improve wheelchair design and research.…”

Section: Introductionmentioning

confidence: 99%

Curb descent testing of suspension manual wheelchairs

Kwarciak

Cooper²,

Fitzgerald³

2008

JRRD

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Abstract-Manual wheelchair users are subjected to wholebody vibrations (WBV) on a regular basis as they traverse obstacles and uneven surfaces. One way users could protect themselves from secondary injuries related to WBV is by using a suspension manual wheelchair. This study investigated the ability of suspension manual wheelchairs to reduce seat accelerations during curb descents of various heights (5, 10, and 15 cm). Sixteen manual wheelchairs (four suspension, four folding, four rigid, and four rigid titanium) were tested. Suspension wheelchairs transmitted significantly lower peak seat accelerations than folding wheelchairs during the 5 cm curb descents (p = 0.048) and significantly lower frequencyweighted peak seat accelerations during the 5 and 10 cm curb descents (p = 0.03 for both heights). However, when the suspension wheelchair Quickie XTR (Sunrise Medical; Carlsbad, California) was removed from the analysis, the suspension wheelchairs were not significantly different from the nonsuspension wheelchairs. When weight was considered, the suspension wheelchairs had significantly lower peak seat accelerations than the lighter rigid wheelchairs during 5 cm curb descents (p = 0.047). While suspension manual wheelchairs offer some reduction in WBV during curb descents, their limitations should be considered when a wheelchair is selected for everyday use.

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“…The 'nonlinearity' in the frequency-dependence of vibration discomfort is partly caused by nonlinearity in biodynamic responses (Matsumoto and Griffin, 2002). The nonlinearities in biodynamic responses to vertical vibration have been shown to vary with the frequency of vertical vibration, although only at frequencies greater than about 2.5 Hz (Zhou and Griffin, 2014a).…”

Section: Comparing Equivalent Comfort Contours For Vibration and Shocmentioning

confidence: 99%

“…This will reduce the calculated vibration dose values for such shocks and so underestimate their severity. The phase between frequency components in a vibration can also influence judgements of discomfort (Matsumoto and Griffin, 2002), but the phases of the standardised frequency weighting filters and bandpass filters arise solely from convenience and not evidence of the phase response appropriate for predicting vibration discomfort. The phase characteristics of filters do not affect r.m.s.…”

Section: Introductionmentioning

confidence: 99%

Frequency-dependence of discomfort caused by vibration and mechanical shocks

2018

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The frequency content of a mechanical shock is not confined to its fundamental frequency, so it was hypothesised that the frequency-dependence of discomfort caused by shocks with defined fundamental frequencies will differ from the frequency-dependence of sinusoidal vibration. Subjects experienced vertical vibration and vertical shocks with fundamental frequencies from 0.5 to 16 Hz and magnitudes from ±0.7 to ±9.5 ms. The rate of growth of discomfort with increasing magnitude of motion decreased with increasing frequency of both motions, so the frequency-dependence of discomfort varied with the magnitudes of both motions and no single frequency weighting will be ideal for all magnitudes. At the frequencies of sinusoidal vibration producing greatest discomfort (4-16 Hz), shocks produced less discomfort than vibration with same peak acceleration or unweighted vibration dose value. Frequency-weighted vibration dose values provided the best predictions of the discomfort caused by different frequencies and magnitudes of vibration and shock. Practitioner Summary: Human responses to vibration and shock vary according to the frequency content of the motion. The ideal frequency weighting depends on the magnitude of the motion. Standardised frequency-weighted vibration dose values estimate discomfort caused by vibration and shock but for motions containing very low frequencies the filtering is not optimum.

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Effect of Phase on Human Responses to Vertical Whole-Body Vibration and Shock—analytical Investigation

Cited by 9 publications

References 15 publications

Muscle activity in the leg is tuned in response to impact force characteristics

Muscle activity in the leg is tuned in response to impact force characteristics

Curb descent testing of suspension manual wheelchairs

Frequency-dependence of discomfort caused by vibration and mechanical shocks

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