US Rule 1-9-1

Commotio Cordis is a rare, but serious, medical condition disproportionately affecting male athletes between approximately 10 – 18 years of age, and is caused by low-impact trauma to the chest by a projectile, such as a lacrosse ball or a body part like an elbow or head. Within minutes, this seemingly mild trauma can cause sudden cardiac arrest and death.

Despite some athletic-related chest trauma occurring without serious injury, Commotio Cordis specifically occurs when the inflicted trauma impacts the area of the athlete’s chest or rib cage over the center of the heart’s left ventricle (the lower-left chamber of the heart) while it is in mid-beat. Since a teenager’s rib cage is more flexible than an adult’s, trauma to this area of the chest can cause the rib cage to touch the heart, triggering ventricular fibrillation (an abnormal heartbeat), which causes blood to stop flowing to the brain. This dynamic leaves male teen athletes particularly vulnerable, and can lead to cardiac arrest in minutes if not treated promptly. In other words, the stars must align for chest impact to provoke Commotio Cordis, but when they do, the result is often fatal.

Commotio Cordis is currently the second leading cause of sudden death in young athletes in the United States, with an estimated 10 – 20 incidents annually, impacting males in 95% of cases. Only an estimated 20% of victims survive the condition, an ominous statistic that is only modestly improved to 35% with prompt administration of Cardiopulmonary Resuscitation (CPR) or defibrillation with an AED, as was used to revive James Hendrik. Notably, 20–30% of documented Commotio Cordis victims collapsed while already wearing chest protection, highlighting a significant vulnerability in equipment that needed to be corrected to help safeguard future potential Commotio Cordis victims.


The National Operating Committee on Standards for Athletic Equipment (NOCSAE) — the nonprofit organization that develops performance and test standards for athletic equipment — established the first performance standard for lacrosse chest-protection against Commotio Cordis, ND200 .

The ND200 standard describes the necessary laboratory equipment and basic requirements needed for testing lacrosse chest-protection equipment to determine if it sufficiently protects against Commotio Cordis.

The Safety Equipment Institute (SEI) — the independent organization responsible for testing the safety of athletic equipment — uses this ND200 standard to test lacrosse chest protectors. Those that pass are believed to provide sufficient protection for reduced risk of Commotio Cordis, and thus receive the SEI Certification mark.