Neither intervention improved outcomes in this small sample. Online mechanisms to support therapist-child communication for exercise progression were insufficient to individualize exercise challenge.

The aims of this study were to (1) characterize anticipatory and reactive postural strategies in typically developing (TD) children and adolescents; (2) determine if TD youth shift from reactive to anticipatory mechanisms based on knowledge of platform movement; and (3) determine whether TD youth further modify postural strategies when additional information about the perturbation is provided. Sixteen typically developing youth aged 7-17 years stood with eyes open on a movable platform that progressively translated anteroposteriorly (20 cm peak-to-peak) through four speeds (0.1, 0.25, 0.5, and 0.61 Hz). Participants performed two trials each of experimenter-triggered and self-triggered perturbations. Postural muscle activity (1000 Hz) of the tibialis anterior, gastrocnemius, quadriceps and hamstrings and 3D whole body kinematics (100 Hz) were recorded. The Anchoring Index and marker-pair trajectory cross-correlations were calculated as indications of body stabilization. The number of steps taken to regain balance/avoid falling were counted. Transition states and steady states were analyzed separately. Generally, the higher frequencies resulted in more steps being taken, lower correlations coupled with greater temporal lags between marker trajectories, and postural muscle activity similar to older adults. The provision of self-triggered perturbations allowed participants to make the appropriate changes to their balance by use of anticipatory postural control mechanisms.

No abstract

The effects of a 5-day virtual-reality based exercise programme on kinematics and postural muscle activity in youth with cerebral palsy ABSTRACT Aims: To determine the effects of a 5-day virtual reality (VR)-based intervention on anticipatory and reactive mechanisms of postural control in children and adolescents with cerebral palsy (CP). Methods: Eleven youth with CP (GMFCS levels I and II), ages 7 to 17, were allocated to intervention (N=5) and control (N=6) groups. Both groups attended balance assessment sessions 1 week apart. Participants in the intervention group received 1 hour one-on-one physiotherapistsupervised VR balance games for 5 consecutive days between assessments. For balance assessments, participants stood erect with eyes open on a movable platform that translated progressively through four speeds in the anterior/posterior direction. Participants performed two trials each of experimenter-triggered and self-triggered perturbations. Postural muscle activity and kinematics were recorded. The Anchoring Index and body segment cross-correlations were calculated as an indication of body stabilization, and the number of steps taken to regain balance/avoid falling were counted. Mann Whitney-U tests for between group differences in change scores were undertaken with an accepted significance level of 0.01. Results: No consistent differences in change scores were identified between groups. Conclusions: There was no effect of a 5-day VR-based intervention on postural control mechanisms used in response to oscillating platform perturbations. Subsequent studies will further tailor VR interventions to patients' functional balance needs.