[Effects of sustained military physical related activity on balance ability]

To evaluate the effects of sustained military physical related activity on balance abilities and the role of visual system in it, so as to provide the basis for precise training.

Fifty-four healthy males (age: 20.28±3.72 y, height: 173.21±5.67 cm; weight: 64.29±5.12 kg) were recruited in this experiment. Multiple military subjects were completed within 36 hours, and the workload was recorded (randomly select 11 people). After military activity, the balance abilities with opened eyes (54 people) and closed eyes (randomly selected 27 people) were evaluated.

In terms of internal load, the heart rates (HR), excess post-exercise oxygen consumption (EPOC) and training impulse (TRIMP) for all exercises were increased significantly in military activity compared with rest (P＜0.05). Regard to balance abilities, compared to the rest with eyes-opened, the sway path-total (SPT), sway path-A-P ( SPAP ), sway path-M-L (SPML), sway V-total (SVT), sway V-A-P (SVAP), and sway V-M-L (SVML)after sustained military activity with eyes-opened were increased significantly (P＜0.05), while sway maximal amplitude-A-P (SMAAP), sway maximal amplitude-M-L (SMAML), and area of 100% ellipse (AE) had no significant changes; Compared to the rest, all indicators after the military activity with eyes-closed were significantly increased (P＜0.05). So vision could control the amplitude and area after the military activity.

Sustained military related activity can damage the balance ability. After sustained military activity, the degree of damage of the balance ability in the closed-eyes is greater than that of the open-eyes, the amplitude and range of the center of gravity are increased, indicates that the visual system plays major role in controlling attitude stability.