Adaptation of postural reactions in seated positions and influence of head posture when exposed to a single sideway perturbation.
(English)Manuscript (preprint) (Other academic)
Mechanical perturbations caused by driving on irregular terrain destabilise the driver which combined with the drivers seated posture may cause musculoskeletal disorders. The aim of this study was to investigate adaptation and the effect of different head postures on seated postural reactions caused by perturbations. Twenty healthy male participants, aged 18-43 years, were tested on a movable platform delivering 17 sideways perturbations (peak accelerations 13.3 m/s2) while the participants held their head in a neutral or a laterally flexed head posture. Surface Electromyography (EMG) was recorded bilaterally in upper neck, trapezius, erector spinae and external oblique, while kinematics were recorded with inertial sensors for the head, trunk and pelvis. EMG amplitudes, muscle onsets and angular displacements in the frontal plane were analysed. In the neutral position, the EMG amplitudes and neck angular displacements significantly decreased with 0.2% and ≥1.6° after repeated perturbations while the onsets remained unchanged. During lateral flexion of the head, the EMG amplitudes also decreased with 0.5% but the muscular onsets increased with ≥9ms. The developed neuromuscular strategy prefers a reduced EMG amplitude. The modest size of the postural reactions during the conditions presented here do not by themselves explain the musculoskeletal disorders found in professional drivers.
Postural balance, Posture, Electromyography, Musculoskeletal pain, Neck muscles
Research subject Physiotherapy; injury prevention
IdentifiersURN: urn:nbn:se:umu:diva-117165OAI: oai:DiVA.org:umu-117165DiVA: diva2:905679