No transfer of gains after a single training session within a virtual environment to fundamental tests of stability

How specific are postural and balance control skills? An important issue for the establishment of effective training and retraining (rehabilitation) programs is whether skills gained while training in laboratory settings can be transferred to performance gains in somewhat different conditions (including every-day life). While there is much evidence showing that for volitional motor tasks the gains in performance (procedural, implicit, knowledge) accrued in practice may not always be transferable to novel task conditions, it is not clear whether the (implicit) knowledge gained in learning postural adjustments can be transferred to measures of balance (reaction to external perturbations) that have not been trained. The objective of the current study was to elucidate what aspects of a postural skill learned within a virtual environment (VE) by healthy adults may be transferable to the performance of standard tests of postural adjustments. Sixteen healthy young adults, aged 20-40 years (mean ± SD = 29.8 ± 2.8 years), were pseudo-randomly assigned to either a training group (Group A) or a no-training, control group (Group B). Group A performed a single training session in a VE in which maintenance of stability on a platform, while travelling along a road scenario and reaching for visual targets (secondary task) were required. Each participant underwent 8 consecutive runs of the task (2:48 m per run). A balance assessment with a given set of perturbations was performed before and after training as well as at 24 hours and 4 weeks post-training. Group B underwent the same assessments but without VE training. The results showed that the Center of Pressure (CoP) displacement tended to decrease over successive balance assessments in both groups, however, this decrease was not statistically significant. Moreover, there was no clear advantage for Group A. Thus, the postural adjustment gains were not transferred to the balance assessment tests. Nonvolitional balance control gains are, in this respect, similar to gains attained in a volitional manual task learning.