The effect of contact sport expertise on postural control

It has been demonstrated that expertise in sport influences standing balance ability. However, little is known concerning how physical contact in sport affects balance ability. The aim of this study was to examine whether differences between contact and limited-contact sport experiences results in differences in postural control. Twenty male collegiate athletes (10 soccer/contact, 10 baseball/limited contact) and ten male untrained students stood quietly on a force plate under various bipedal and unipedal conditions, with and without vision. Significant differences for sway area and COP speed were found between the soccer players and the other two groups for unipedal stances without vision. Soccer players were found to have superior postural control compared with participants involved in limited contact sport or no sport at all. Contact sports may lead to increased postural control through enhanced use of proprioceptive and vestibular information

Illustration of the experimental setup.

<p>Participants performed actual and imagined dorsiflexion of their right foot at three different EMG levels (10, 40 or 80% of the maximum voluntary contraction).</p

MEP amplitude of ECR and FCR.

<p>The mean MEP amplitudes and standard deviation of the ECR and the FCR during actual and imagery DF. * denotes p<0.05 levels of significance for comparison between the three intensities. † denotes p<0.01 levels of significance in a comparison with the resting condition (i.e. 100). Values are mean ± SD.</p

MEP waveform.

<p>Raw motor-evoked potential (MEP) waveform of the ECR elicited by single-pulse TMS in a participant at three different intensities (10, 40 and 80%) in the actual and imagery dorsiflexion (DF) task and the resting condition. Fifteen wave forms at each force level are superimposed.</p

Correlation of MEP amplitude.

<p>Relationship between MEP amplitude of ECR and FCR during the imagery of DF and of the actual DF. Each circle denotes a 10% (white circle), 40% (grey circle) and 80% (black circle) of MEP for all subjects. The dotted line indicates the linear regressions in the range of 0 to 200%.</p

Hitting performance of each participant regarding the ball-bat contact location, contact time, and bat head velocity.

<p>Hitting performance of each participant regarding the ball-bat contact location, contact time, and bat head velocity.</p

The mean horizontal angular velocity of the eyes and head during the four time periods of the Slow Ball Task.

<p>* <i>p</i> < 0.05.</p

The arm-style pitching machine with a photo-sensing diode.

<p>The arm-style pitching machine with a photo-sensing diode.</p

Eye (θ_eye) and head angles (θ_head) on the global XY plane when the batters observed a moving baseball.

<p>Eye (θ_eye) and head angles (θ_head) on the global XY plane when the batters observed a moving baseball.</p

Ball-bat contact and directions of head, eye, and ball in Slow Ball Task.

<p>A) The left column indicates each participant’s ball-bat contact location, with the mean and standard deviation. B) The middle column indicates each participant’s θ_eye, θ_head and resultant direction (θ_eye+ θ_head) from the ball’s release to its contact with the bat during the Slow Ball Task. C) The right column indicates the resultant direction, estimated direction of the launched ball (ball), and difference between the resultant direction and ball direction from its release to its contact with the bat. The dashed line at 0 ms indicates the time the ball was released, and the dash-dot line indicates the time at which the bat swing was expected to be initiated.</p