Bilateral associations of low-level unilateral performance: an unremarked aspect of limb control.
The experimenters examine upper limb movement discrimination performance in an arm-raising task for bilateral associations of low-level unilateral performance. On a cue from the experimenter, young adults (n = 23) with no history of shoulder injury raised either their left arm, right arm, or both together in a forward flexion movement until their hand or hands contacted an unseen, adjustable, overhead stop. The participant then judged which of the 5 possible stop positions, in the 12-20 degrees range forward of true vertical, the participant had contacted on the particular trial. Results showed that for the 16 participants whose best performance was in 1 of the unimanual conditions discrimination scores in the bilateral condition were equivalent to those of their worse-performing limb. For the 7 participants whose best discrimination performance was obtained on bimanual arm-raising, scores for the 2 unimanual conditions were equivalently low. Therefore, when a single limb that can perform well operates in conjunction with a limb performing at a lower level, the consequence is lowering the bimanual movement discrimination performance.
Vucetic
Adriana
A
Physiotherapy, Faculty of Health Sciences, University of Sydney, Sydney, NSW, Australia.
Holmes
Michelle
M
Adams
Roger
R
Waddington
Gordon
G
D000328:Adult; D000704:Analysis of Variance; D019540:Area Under Curve; D001132:Arm; D004193:Discrimination Learning / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007699:Kinesthesis / Q000502:physiology*; D008297:Male; D009048:Motor Skills / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D012016:Reference Values; D013028:Space Perception / Q000502:physiology; D013037:Spatial Behavior / Q000502:physiology