Asymmetric interlateral transfer of motor learning in unipedal dynamic balance.

Interlateral transfer of learning between the legs in body balance training is a topic of theoretical and practical interest, but it has been left untouched in previous research. In this investigation, we aimed to evaluate the magnitude and asymmetry of interlateral transfer of balance stability following the practice of a challenging task of unipedal support on an unstable base. Thirty participants (18-30 years old) were assigned to two groups practicing either with the right or the left leg. Training consisted of a single practice session of unipedal balance on a platform free to sway in the anteroposterior direction. Balance time (off ground) of either leg in 10-s trials was compared across pre-test, post-test, and 7-day retention. Post-test indicated that both groups had similar performance gains with the trained leg, and equivalent transfer to the transfer leg. Analysis of retention indicated further balance improvement with both transfer legs, while practice with the right leg led to the superior transfer to the untrained leg as compared to the opposite transfer direction. These results suggest that persistent transfer of learning effects for unipedal dynamic balance is bilateral but more prominent in the right-to-left direction.