Turning away from whiplash. An EMG study of head rotation in whiplash impact.
J Orthop Res
; 23(1): 224-30, 2005 Jan.
Article
em En
| MEDLINE
| ID: mdl-15607897
ABSTRACT
OBJECTIVE:
To determine the response of the cervical muscles to whiplash-type perturbations through low-velocity frontal impacts when the head is rotated to the right and left.METHODS:
Twenty healthy volunteers were subjected to increasing acceleration in low-velocity frontal impacts, randomly with head rotated either left or right. Bilateral EMG of the sternocleidomastoids, trapezii, and splenii capitis and acceleration of the sled, torso, and head were recorded.RESULTS:
With either direction of head rotation at the time of impact, the muscle responses increased with increasing levels of acceleration (p < 0.01). The time to onset and peak electromyogram for all muscles progressively decreased with increasing levels of acceleration. With the head rotated to the left, the left trapezius generated 77% of its maximal voluntary contraction (MVC) EMG (more than double the response of other muscles). In comparison, the right trapezius generated only 33% of its MVC. The right sternocleidomastoid (25%) and left splenius muscles (32%), the ones responsible for head rotation to the left, were more active than their counterparts (the left sternocleidomastoid generated only 5% of its MVC EMG and the right splenius 9%). On the other hand, with the head rotated to the right, the right trapezius generated 71% of its MVC EMG, while the left trapezius generated only 30% of this value. Again, the left sternocleidomastoid (27% of its MVC EMG) and right splenius (28% of its MVC EMG), being responsible for head rotation to the right, were more active than their counterparts (the right sternocleidomastoid generated only 4% of its MVC EMG and the left splenius 13%).CONCLUSIONS:
Frontal impacts tend to generate the most muscle activity in the ipsilateral trapezius muscle, increasing the risk of their injury.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Traumatismos em Chicotada
/
Movimentos da Cabeça
/
Músculos do Pescoço
Tipo de estudo:
Etiology_studies
Limite:
Adult
/
Humans
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article