ABSTRACT
The aim of this study was to analyse the effects of the removal of vision on postural performance and postural control in function of the difficulty and specificity of the posture. Twelve elite gymnasts were instructed to be as stable as possible with eyes open and eyes closed in three postures: bipedal, unipedal, and handstand ranked from the less difficult and less specific to the more difficult and more specific. The ratios eyes closed on eyes open, computed on CP surface and CP mean velocity, which respectively represents postural performance and postural control, were similar in the bipedal and handstand postures. They were highly increased in the unipedal one. The effect of the removal of vision and so the role of vision on body sway was not directly linked to the difficulty or specificity of the posture; other tasks' characteristics like the segments configuration also played a role.
Subject(s)
Gymnastics/physiology , Posture , Visual Perception , Adolescent , Adult , Humans , Male , MovementABSTRACT
This study analyzed the effect of head position and visual condition on the control of balance in handstand, a gymnastics posture that necessitates adaptation of sensory information processing. Five expert gymnasts participated. Centre of pressure trajectories and kinematics of different body segments were recorded. The gymnasts were instructed to maintain three handstands as long as possible in four head positions, with and without vision. Performances and postural stability was much better in the standard and dorsiflexion positions than in the aligned and ventroflexion positions under the two conditions of vision. Performances were lower without vision in the standard and dorsiflexion position. If vision clearly plays an important role, yet the tonic neck reflexes also seem to contribute greatly to control body sways during inverted posture.
Subject(s)
Head Movements/physiology , Postural Balance/physiology , Posture/physiology , Proprioception/physiology , Visual Perception/physiology , Adult , Afferent Pathways/physiology , Biomechanical Phenomena , Cervical Vertebrae/innervation , Cervical Vertebrae/physiology , Feedback/physiology , Female , Gymnastics/physiology , Humans , Male , Muscle Contraction/physiology , Muscle, Skeletal/innervation , Muscle, Skeletal/physiology , Psychomotor Performance/physiology , Reflex/physiology , Sensory Deprivation/physiology , Vestibule, Labyrinth/physiology , Zygapophyseal Joint/innervation , Zygapophyseal Joint/physiologyABSTRACT
The purpose of this study was to investigate the transfer of postural ability by comparing the level of performance and postural control of elite gymnasts in postures specifically trained or not. Fifteen elite gymnasts were asked to stand as still as possible with eyes opened in three conditions: bipedal, unipedal and handstand. Surface and mean velocity of the centre of pressure motions were used to quantify respectively performance and postural control. A ranking was made for each parameter to determine the level of each subject. As a whole, the subject's level of postural performance and control in one condition was not correlated to the corresponded level in another condition. Therefore, postural ability of elite gymnasts in the handstand is not transferable to upright standing postures.
