ABSTRACT
The most active muscular contractions during the upward phase of the airborne (flying) phase are by the scaleni muscles. They initiates flexion of the cervicothoracic junction and the muscles of the upper neck, which act to extend the head. In the thoracolumbar and abdominal regions, the muscle groups that during propulsion acted to support the vertebral axis and balance compressive forces have a change in role. During the peak (second) phase of the airborne (flying) phase, release of the abdominal muscles and contraction of the erector spinae result in extension of the thoracolumbar and lumbosacral spine.
