INVESTIGADORES
FELICE Carmelo Jose
artículos
Título:
Arm EMG during abduction and adduction: hysteresis cycle
Autor/es:
POLITTI, JULIO CESAR; FELICE, CARMELO JOSÉ; VALENTINUZZI, MÁXIMO EUGENIO
Revista:
MEDICAL ENGINEERING & PHYSICS
Referencias:
Año: 2003 vol. 25 p. 317 - 320
ISSN:
1350-4533
Resumen:
The electromyographic
study of the muscles involved in the complex movements of the shoulder is one
way to quantifying this joint´s dynamic behavior. In particular, the deltoid
medium EMG produced a phenomenon similar to a hysteresis cycle when its
amplitude was plotted as a function of the lateral angular position during a
static, step by step, sequential abduction-adduction of the arm. Such cycle was
consistently repeated in 16 subjects (12 males and 4 females). The paired
Student t-test, after comparing the mean EMG values of the rectified wave for
the same arm opening angle between abduction and adduction, produced a highly
significant difference (a < 0.001) in all subjects. In all likelihood, it
manifests the participation of muscles other than the deltoid medium in the
overall movement (as for example, the anterior and posterior deltoids), that
is, they are collaborating muscles that are different in the opening or lifting
of the arm from those involved in its closure or lowering. Thus, it is
concluded that a quantifiable and significant deltoid medium EMG difference has
been demonstrated when the muscle is either ready to abduction or ready to
adduction. The effect is fully reproducible between 0 and 90 degrees of an arm
in static position within the scapular plane.