Date of Award

May 2017

Degree Type


Degree Name

Doctor of Philosophy



First Advisor

Wendy Huddleston

Committee Members

Stephen Cobb, Tom Kernozek, Brooke Slavens, Jinsung Wang


Biomechanics, Motor Control, Sports


The purpose of this dissertation was to explore how cognitive factors contribute to non-contact anterior cruciate ligament (ACL) injury risk in young females. We specifically wanted to develop a better understanding of how the movement patterns of females with varying cognitive attributes/abilities are influenced as the cognitive demands associated with a task progress (Chapter 2). We also wanted to explore how task-related cognitive demands influence movement. We altered the cognitive demands associated with a movement task by requiring participants to execute a maneuver while attending to a simulated teammate (Chapter 3) or to a ball overhead (Chapters 4 & 5). In addition, we also imposed temporal constraints on decision-making (i.e. movement selection) by requiring participants to maneuver in response to an external stimulus (Chapters 4 & 5).

To investigate the influence of individual cognitive attributes, we utilized a computer-based clinical test to assess cognitive function for a group of 45 uninjured young females. The cohort was delineated into groups based on their performance on the reaction time component of the cognitive test (slow reaction times vs. fast reaction times). Both groups also performed a lateral cutting task in two conditions (un-planned, pre-planned). For the un-planned condition, participants initiated a trial and then reacted to a stimulus that dictated the movement they were to perform (land, jump, or cut), which imposed temporal constraints on decision-making. During the pre-planned condition, participants knew to perform the cut prior to initiating a trial. We expected that the mechanics of the participants with slower reaction times would be influenced to a greater extent when there were temporal constraints on decision-making. Interestingly, this was not the case. In fact, we found that the participants with slower reaction times landed with greater forces regardless of the cognitive demands associated with the task. It appears that cognitive function plays a prominent role in an individual’s ability to control their movement, even when there are not additional cognitive demands imposed.

Our assessment of the impact of additional task-related cognitive demands on movement included 20 uninjured young females with basketball experience. In our first analysis, we found that requiring participants to perform a basketball chest pass immediately after landing from a cut altered their mechanics in a manner that may increase ACL injury risk in comparison to trials performed without the pass. We also performed an analysis where participants performed a drop vertical jump task with and without additional cognitive demands. When temporal constraints were imposed on decision-making, participants demonstrated landing mechanics that may increase their ACL injury risk compared to baseline (i.e. trials performed without additional cognitive demands). We found similar results when participants were required to attend to a ball suspended overhead during execution of the drop vertical jump. Our findings indicate that additional task-related cognitive demands have a prominent influence on movement.

The results of this dissertation highlight how cognitive factors (individual and task-related) may contribute to non-contact ACL injury risk. Failure to incorporate cognitive factors could limit the effectiveness of ACL injury risk screening and prevention.

Included in

Kinesiology Commons