Limb And Eye Dominance In Limb Selection In A Step And Reach Task

Step and reach movements are inherent in sport but constraints underlying preferred arm and leg combinations are unexplored. PURPOSE: To examine influences of preferred arm, leg, and eye on arm/leg combination choices in a step and reach task under varying visual field conditions. METHODS: After informed consent, 15 subjects (21.3 ± 0.8 yrs) were tested over three days for laterality performance in vision, motor skills, and response time. Response time tasks involved left or right visual cues requiring a spatially congruent left or right arm response. A center visual stimulus enabled a choice of either arm. One condition required only an arm reach (Reach), another required a step and reach (StepReach). In some conditions the subjects used both eyes or only one eye. A total of 300 trials were conducted over two days and analyzed by REANOVA for speed and limb use patterns. RESULTS: All subjects were right-handed, and 10 of 15 were right eye dominant. Speed was faster (p < .001) in the Reach (533 ± 59 ms) versus the StepReach (932 ± 164 ms) and faster (p = .009) with both eyes (713 ± 102 ms) versus left eye (742 ± 88 ms) and right eye only (742 ± 111 ms). Left-eyed persons were slower (p = .003) with center and right stimuli compared to right eyed persons, and this effect was pronounced in the StepReach condition. Post-hoc contrasts revealed different (p = .029) patterns of arm use between Reach and StepReach; in both conditions the spatially congruent arm was used 91% (± 22) of the time for left and right stimuli and the dominant right arm was used in center stimuli 81% (± 27) of the time, but in StepReach the congruent left arm in left side stimuli was used only 49% (± 40) of the time. These findings were unaffected by which eye was used or a person’s dominant eye. In StepReach the spatially congruent leg was used 60% of the time which was not significantly different than the use of the left (46%) and right (54%) legs in the center stimulus. In StepReach an ipsilateral arm/leg combination was faster than contralateral (888 ± 205 ms vs. 1018 ± 160 ms; p < .001) and was used 70% of the time. CONCLUSIONS: In rapid step and reach tasks task there may be a preferred ipsilateral limb pattern consistent with arm dominance, but contralateral movements are common. The use of both eyes may produce faster movements, but may have little effect on the arm/leg combination used.