Study Design

JUMP-ACL ( Joint Undertaking to Monitor and Prevent ACL Injury) is a collaborative multi-site prospective cohort study of neuromuscular risk factors for Anterior Cruciate Ligament (ACL) injury.

The study is based at the:

U.S. Military Academy in West Point, NY
U.S. Naval Academy in Annapolis, MD
U.S. Air Force Academy in Colorado Springs, CO

The study is jointly coordinated by:

University of North Carolina at Chapel Hill
Uniformed Services University of the Health Sciences

Co-investigators on the study are based at:

Duke University
Orthopedics Center in Rockville, MD
Plymouth State University
Virginia Commonwealth University
Old Dominion University

When the cadets or midshipmen arrive in July of each year to begin their 4-year officer training, some of them are enrolled as subjects in the study. The study is currently enrolling subjects. When enrollment is complete, in 2008, the cohort will over 5,000 subjects. Approximately 40% of the cohort is female.

Those cadets or midshipmen entering the study undergo a baseline assessment protocol. The baseline assessment protocol includes:

motion analysis during a jump-landing task
strength assessment
postural alignment assessment
questionnaire (injury history and sports participation).

Subjects are then followed prospectively throughout their academy careers for incident ACL injury. ACL injuries are identified by the participating clinicians at the academies.

Computer Analysis of ACL Movement

Study Aims

Aim 1 : To determine the association between neuromuscular risk factors, including poor jump-landing technique, and the rate of ACL injury.

Aim 2 : To determine the association between selected non-neuromuscular risk factors, (gender, anatomical factors, hormonal factors), and the rate of ACL injury.

Aim 3 : To quantify differences in neuromuscular risk factors between men and women.

This focus of this prospective cohort study is neuro-muscular risk factors for ACL injury, with an emphasis on neuromuscular factors that exhibit gender differences. Despite intensive research efforts, the cause of Anterior Cruciate Ligament injury remains elusive, beyond the simple observation that women are at higher risk than men. We hypothesize that the etiology of ACL injury is multi-factorial in nature, with neuromuscular risk factors playing a critical role, especially from a prevention standpoint. This hypothesis is suggested by biomechanical studies indicating that the increased risk in women may be largely due to neuromuscular risk factors, such as gender differences in muscle strength and human movement. Unlike anatomical and hormonal risk factors, neuromuscular risk factors are readily modifiable and are amenable to intervention.

The study uses a standardized tool for scoring poor jump-landing technique, the Landing Error Scoring System (LESS), 3-D motion analysis, postural alignment measures, and muscle strength testing to examine the association between neuromuscular risk factors and ACL injury. The study will also investigate demographic, hormonal, and anatomical risk factors that have been advanced in the literature as causes of the excess of ACL injuries in women. Ultimately, the research will make a significant contribution to our understanding of the causes of ACL injury, with particular regard to those risk factors that appear to predispose women to ACL injury.