非表示:
キーワード:
-
要旨:
In comparison with non-athletes, there is little doubt that gymnasts have better spatial orientation
during complex sport-specific movements, like double or triple “twisting somersaults”
or similar exercises. An understanding of the specific processes of spatial training and their
function in a higher level of multi-axial spatial orientation remains unclear. One must consider
the role that motor learning in any sensorimotor system contributing to orientation might
play, e.g. smooth pursuit. Are there measurable differences in the dynamics of these behaviors
between gymnasts and non-athletes due to their respective levels of training? We sought
to investigate the relationship between smooth pursuit performance and the spatial orientation
needed during fast multi-axial whole body rotations. The subjects’ (gym: n = 9, age: 10–12
years, control: n = 10, age: 10–12 years) smooth pursuit eye movements were recorded using
a monocular video nystagmography system (SMI). They were seated in the dark with head
and body fixed. The stimulus was a laser target moving horizontally with a sinusoidal velocity
profile. Maximum stimulus velocities of 60/s, 120/s, 140/s, 160/s, were used, with a short
break between tests. The gymnast group was tested again after a three-week break in their
gymnastic training. Pursuit gain was calculated as the ratio of the amplitude of the best-fit
sine wave for the slow-component eye velocity to the amplitude of the stimulus velocity. Any
additional training effect on pursuit velocity, e.g. video games, could be excluded. Although in
both groups the gains were reduced with higher maximum stimulus velocity, the results show
significantly higher gains for the gymnasts during the 120/s test (gain ± s.d., gym.:0.23±0.10,
n=9, control: 0.14±0.08, n=10; p=0.022, Z=-2.289, Mann-Whitney-U) and 140/s (gain ± s.d.,
gym.:0.19±0.12, n=9, control: 0.08±0.05, n=10; p=0.010, Z=-2.536, Mann-Whitney-U). For
60/s and 160/s there was only a tendency toward higher gains for the gymnasts. After the
break in training, the gymnasts gains were significantly reduced at 120/s and 140 /s (120/s:
0.20±0.09, n=9; p=0.028, Z=-2.198; 140/s: 0.12±0.07, n=9; p=0.033, Z=-2.136, Wilcoxon).
There was also a clear reduction at 60/s and 160/s, but not significant. Smooth pursuit in
healthy humans shows a saturation (gain>0.8, binocular) of approximately 100/s [1]. So tests
with peak velocities of 120/s and 140/s are clearly above this saturation level. The results
demonstrate that high-performance gymnasts show a training-dependent modification of their
maximum velocity for smooth pursuit.
