Critical features of training that facilitate adaptive generalization of over ground locomotion

Abstract

When subjects learn motor tasks under novel visuomotor conditions variations in sensory input during training facilitate adaptive generalization. We tested the hypotheses that training with multiple sensory input variations is more effective than a single or no variation and that training must include critical features of the criterion task. Normal adults were pre- and post-tested on an obstacle avoidance task while wearing visual distortion lenses after treadmill walking (Experiment 1), or balance training (Experiment 2). Subjects were randomized to training groups in which they wore either: (1) three different visual distortion lenses, (2) a single pair of visual distortion lenses, or (3) sham lenses. Post-tests were done while wearing novel lenses. In Experiment 1 subjects who trained with multiple lenses adapted better than single or sham lens groups. The single lens-training group with magnifying lenses adapted better than the other single lens groups. In Experiment 2, training for dynamic balance, alone, did not increase training efficacy. Thus, training for an obstacle avoidance task in a novel visual environment required a critical feature of the criterion task: locomotion. Constant practice with a single lens was successful only if the best lens was selected, but the best lens could not be known ahead of time. Therefore variable practice with multiple lenses on a task that included a critical feature of the criterion task was the best training strategy to enhance adaptive generalization.

Figure 1

Plan view of the FMT obstacle course. Modified from Moore et al (18). Used with kind permission of Springer Science and Business Media.

Figure 2

Mean scores (± one standard error of the mean) by test dates and groups for obstacle errors by - Experiment 1: treadmill training; and Experiment 2: wobble board training. A univariate ANOVA on the obstacle errors for the pretest revealed a significant main effect for the factor Experiment (★★★) and hence was used a covariate for further analysis. A RMANOVAs on obstacles with the pretest as a covariate revealed significant main effects for Session (★, two levels: posttest and retention) and Experiment (★★, two levels: Treadmill and Wobble Board).

Figure 3

Mean scores (± one standard error of the mean) by sessions and group for time by - A) Experiment 1: treadmill training; and B) Experiment 2: wobble board training. A RMANOVAs on time revealed a significant main effect for Session (★, three levels: pretest, posttest and retention) and a significant interaction between Sessions, Lens Groups and Experiment.

Figure 4

Mean (± one standard error of the mean) percentage change in time by each of the five training groups of the post test (Session 5, 20° shift right lenses) in Experiment 1 - Treadmill walking. A univariate ANOVA across lens groups on the percent differences of time for pretest to posttest revealed: 1) the variable lens group is significantly different from the sham, the single lens minifying and the single lens up/down groups (★) and 2) the single lens magnifying is significantly different from the sham, and the single lens up/down groups (★★).