Augmented Feedback Response Prediction by Peak Vertical Ground Reaction Force in Adolescent Female Athletes.

Background and purpose: Anterior cruciate ligament (ACL) tears often occur due to non-contact mechanisms in landing within females. Impact loading and aberrant landings may be addressed with augmented feedback training. The purpose of this study was to identify which female athletes most readily respond to a single session of augmented feedback to attenuate vGRF, by considering baseline peak vGFR and change in vGRF during training.

Design: Repeated Measures.

Methods: One hundred, forty-seven female athletes landed from 50 cm onto two force platforms with and without augmented feedback of vertical ground reaction force (vGRF), vGRF symmetry, and lower extremity position. Each performed six baseline trials and two sets of six training trials with cues. Following training, athletes completed six post-feedback trials (with no feedback) and six dual-task (transfer) trials where they randomly caught a basketball during landing. Peak vGRF was measured. Mean responses were reported for the sets of six trials. Participants were grouped based on their responses to training. Linear regression was used to indicate how well initial performance and response predicted the final response.

Results: Four groups were identified, with 107 participants showing high baseline ground reaction forces and response to training. Only 23 participants (16.4%) did not respond to training. Baseline vGRF predicted post-feedback vGRF and transfer task vGRF (R2=0.508 and R2=0.400) across all participants. When change in vGRF was assessed following two blocks of augmented feedback training, prediction of responders improved with post-feedback vGRF and transfer vGRF (R2=0.911 and R2=0.761).

Conclusions: The combination of both baseline ground reaction force and response to initial training is more accurate than baseline measures alone in identifying those who respond to training. Assessing initial response to training may be necessary to more accurately identify individuals most likely to benefit from augmented feedback training and who may require further evaluation and training.

Level of evidence: 2b.