effect of lifting on trunk muscles motor control in athlete and non-athlete subjects

ABSTRACT

Spinal injury especially during occupational lifting is one of the most common neuromuscular disorders in the general population of the world. Asymmetric motions of trunk frequent bending and twisting, lifting and forceful activities contribute to spine disorders. Sport as a comprehensive activity might be able to cause less force to the spine and decrease spinal injuries. The purpose of present study was to determine the effect of lifting on motor control pattern during combined symmetric and asymmetric trunk motions on athlete and non-athlete subjects. Seventeen non-athlete female subjects and seventeen athlete female subjects performed to lift four loads [5,7,9, 12 kilogram] at symmetric and asymmetric conditions. Under each condition temporal parameters of motor control were measured on flexor and extensor of trunk muscles. In two groups of athletes and non-athletes with increasing load, muscles begin their activity faster [P<0.05]. No significant change was found at asymmetric condition. Also, in athletes premotor time of muscles during lifting was less than non-athletes. With increasing load, according to the feed forward control mechanism and awareness of subjects from amount of loads, muscles quickly prepared to contract for starting the movement. It seems that the response of movement on the neuromotor system of athletes is preprogrammed and automatic due to sport experience. Actually muscles have anticipation activity