Acquisition, Retention, and Transfer Effects of Landing Training to Increase Foot Progression Angle During Bilateral Drop Landings.

Abstract

Foot position during landing directly influences knee mechanics. Thus, the purpose of this study was to determine success in practicing, repeating, and transferring a desired foot progression angle (FPA) during landing, as well as changes in knee mechanics. Twenty females were randomly assigned to a control or verbal instruction group. On day 1, each group performed 40 drop landings. The verbal instruction group was instructed to "Land with 30 degrees of external rotation" before every trial. Feedback was provided on a terminal schedule in the form of knowledge of FPA error. On day 2, retention was assessed with 5 drop landings, while transfer was assessed during a 2-step stop-jump landing. Repeated-measures analyses of variance (2 × 4 [group × time]) were used to assess the influence of verbal instruction on knee mechanics. Participants who received verbal instruction exhibited increased FPA. They also demonstrated increased initial contact knee abduction during acquisition and retention. For all participants, initial contact knee flexion increased, while peak knee adduction moment decreased during acquisition. While the verbal instruction cue was effective in promoting an increase in FPA and reducing some ACL injury risk factors during practice and retention, this cue may only be effective to tasks similar to what was practiced.