Interference of balance tasks revisited: Consolidation of a novel balance task is impaired by subsequent learning of a similar postural task.

BACKGROUND

Interference effects have repeatedly been demonstrated for simple motor tasks but not for the complex whole-body task of balancing. It was therefore assumed that different balance tasks are so specific that they do not elicit interacting adaptations; neither in a positive (contextual interference) nor in a negative way (disruption of motor consolidation).

RESEARCH QUESTION

Is a novel balancing task susceptible to interference if a similar balance task is learned shortly afterwards?

METHODS

The common A-B-A interference intervention design was applied. Participants were assigned to one of four intervention groups that differed with respect to task B. All four groups performed postural task A on a rocker board device (6 series of 8 trials of 8 s). Shortly after completion of task A, participants performed their respective task B (postural wobble board (P-WB), ballistic force, accuracy) or rested (control group). 24 h later, all groups performed a retention test of task A consisting of one series of 8 trials. To test for interference, we calculated repeated mixed design analysis of covariance (ANCOVA).

RESULTS

For the retention test, the ANCOVA revealed a significant TIME*GROUP interaction (p = .010), which was followed up by separate Bonferroni-corrected post-hoc tests for each group. These tests showed a significant performance decrease for the P-WB group (p = .016) but no change in performance for the other three groups.

SIGNIFICANCE

In contrast to previous findings, our results indicate that the complex whole-body task of balancing is susceptible to interference, but only, when task B consists of a similar balance task. This is of great functional relevance as for example fall prevention programs incorporate many different balance tasks to prepare participants for all sorts of situations. In such interventions, it seems therefore advisable to apply a random instead of a blocked practice design.