Robin C Redfield

United States Air Force Academy, Air Force Academy, CO, USA

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Publications (2)1.05 Total impact

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    Article: Benign paroxysmal positional vertigo in mountain bikers.
    Dominique Vibert, Robin C Redfield, Rudolf Häusler
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    ABSTRACT: We evaluated 4 men who had benign paroxysmal positional vertigo (BPPV) that occured several hours after intensive mountain biking but without head trauma. The positional maneuvers in the planes of the posterior and horizontal canals elicited BPPV, as well as transitory nystagmus. This was attributed to both the posterior and horizontal semicircular canals (SCCs) on the left side in 1 patient, in these 2 SCCs on the right side in another patient, and to the right posterior SCC in the other 2 patients. The symptoms disappeared after physiotherapeutic maneuvers in 2 patients and spontaneously in the other 2 patients. Cross-country or downhill mountain biking generates frequent vibratory impacts, which are only partially filtered through the suspension fork and the upper parts of the body. Biomechanically, during a moderate jump, before landing, the head is subjected to an acceleration close to negative 1 g, and during impact it is subjected to an upward acceleration of more than 2g. Repeated acceleration-deceleration events during intensive off-road biking might generate displacement and/or dislocation of otoconia from the otolithic organs, inducing the typical symptoms of BPPV. This new cause of posttraumatic BPPV should be considered as an injury of minor severity attributed to the practice of mountain biking.
    The Annals of otology, rhinology, and laryngology 01/2008; 116(12):887-90. · 1.05 Impact Factor
  • Article: Motion measurements in the jumping of a mountain bike.
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    ABSTRACT: Mountain biking is generally a much more extreme sport than road cycling. It exhibits large motions and loadings, and involves complicated interactions between the rider and the bike. A dynamic model of a mountain bike and rider is being developed that requires validation by comparing predicted and actual dynamic performance. This paper reports the first step by acquiring experimental data of a moderately extreme maneuver; a mid speed jump and landing and was undertaken as part of a senior level instrumentation class. Both biomechanics and mechanical engineering studies can benefit from this data. A mountain bike and rider are instrumented for video marker tracking during the jumping maneuver. Positions are numerically differentiated to obtain velocities and accelerations. This motion data is examined for continuity and reasonableness. Future manipulation of this data will provide joint reaction data and center of mass motion for a bicycle/rider model validation.
    Biomedical sciences instrumentation 02/2004; 40:43-50.