European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society
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Frontal impacts are a common cause of whiplash injury. Yet, volunteer studies of the cervical muscular response and head-neck kinematics to frontal impacts are uncommon, and specifically, the effect of an offset (anterolateral) frontal impact on the resultant muscle responses is unknown. The purpose of this study was to determine the response of the cervical muscles to increasing low-velocity frontal impacts offset by 45 degrees to the right, and to compare the quantitative effects of expected and unexpected impact. ⋯ The kinetic variables and the electromyographic variables regressed significantly on the acceleration (p<0.01). In response to right anterolateral impacts, muscle responses were greater with higher levels of acceleration, and more specifically, when a frontal impact is offset to the subject's right, it results in not only increased EMG generation in the contralateral trapezius, but the splenius capitis contralateral to the direction of impact also bears part of the force of the neck pertubation. Expecting or being aware of imminent impact plays a role in reducing muscle responses in low-velocity anterolateral impacts.
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The goal of this study was to observe scoliotic subjects during level walking to identify asymmetries--which may be related to a neurological dysfunction or the spinal deformity itself-and to correlate these to the severity of the scoliotic curve. ⋯ The most significant and marked asymmetry was seen in the transverse plane, denoted as a torsional offset of the upper trunk in relation to the symmetrically rotating pelvis. This motion pattern was reflected by a ground-reaction-force asymmetry of the free rotational moment. Further studies are needed to investigate whether this behaviour is solely an expression of the structural deformity or whether it could enhance the progression of the torsional deformity.