# Rotational vs. Straight Landings: Exploring Task-Specific Responses to Inform ACL-Injury Risk Screening

## TL;DR

The study compares rotational and straight landings to understand how they affect knee injury risk, finding that rotational landings highlight sex-specific biomechanical differences.

## Contribution

The study introduces new insights into rotational landing biomechanics and sex-specific responses, supporting their use in ACL injury risk screening.

## Key findings

- Rotational landings emphasize hip flexion angles and peak vertical ground reaction forces at initial contact.
- Sex-specific differences in ankle dorsiflexion and time to peak vertical GRF were observed during rotational landings.
- Unilateral landings revealed more biomechanical differences and sex-specific variations compared to bilateral landings.

## Abstract

Rotational landing tasks have the potential to support screening methods for anterior cruciate ligament (ACL) specific injury risk. However, alterations in lower-limb kinematics and kinetics during rotational landings, and sex-specific responses, are currently largely unexplored. This study, therefore, explored the differences in lower-limb kinematic and kinetic characteristics between rotational and straight landings, and the sex-specific responses to rotational landings. Thirty-six healthy team-sport athletes (eighteen males and eighteen females) performed straight bilateral and unilateral landings, and rotational (clockwise and counterclockwise) landings, from a box while lower-limb kinematics and ground reaction forces (GRFs) were recorded. Rotational landings were found to emphasise (p < 0.001) hip flexion angles at initial contact and peak vertical GRF. Differences between males and females (p < 0.001) were identified during rotational landings (but not straight landings) for peak ankle dorsiflexion and time to peak vertical GRF, with significant task-sex interactions. Compared to the bilateral landing, unilateral tasks affected the magnitude or highlighted sex-specific differences for nine and one biomechanical characteristics, respectively. Together, these outcomes provide further insights into lower-limb kinematic and kinetic responses to rotational landings. These findings offer additional support for the use of rotational, as well as unilateral elements, for ACL-injury risk screening practice.