What is HARM?

HARM is the Head Acceleration Response Metric, a head impact severity metric used to calculate the effectiveness of protective gear based on impact, distance, and acceleration. This statistic helps researchers communicate the value of helmets, helmet covers, and other protective gear.

Do Guardian Caps reduce HARM?

Guardian Caps were tested at the Shriram Center for Bioengineering and Chemical Engineering on the Stanford University campus. Lab impact tests were conducted on three helmet models with and without a padded helmet shell cover equipped to each. These were the results:

According to the Stanford University Study:

“In 33 of the 36 helmet shell test conditions in this study, the use of the padded helmet shell cover resulted in a lower average HARM value than the bare helmet tests. For all three helmet models, the percentage reduction in HARM at shell impact locations decreased as impact velocity increased. In all 18 facemask test conditions, the use of the padded helmet shell cover resulted in a lower average HARM value than the bare helmet tests.

Overall, HARM values were reduced in laboratory impact tests by an average of 25% at 3.5 m/s (range: 9.7 to 39.6%), 18% at 5.5 m/s (range: − 5.5 to 40.5%), and 10% at 7.4 m/s (range: − 6.0 to 31.0%).”

Guardian Caps reduced HARM by up to 40% and produced an average reduction of 25%.

How do Guardian Caps reduce HARM?

Physics says that an outer “soft” material of the proper density, stiffness and energy absorbing properties reduces the initial severity of the impact. The hard shell then has lower forces transmitted to it, and in turn conveys lower forces to the interior soft helmet padding and then lower forces to the head. Very similar to a NASCAR driver and the soft wall technology that tracks have adopted or even automobiles and the soft bumpers and airbags that are now required. The Guardian Cap serves the same purpose for an athlete’s head—a soft shell barrier between it and impact.

How does this translate to the football field?

Due to the continued success of Guardian Caps, the NFL has mandated Caps during all preseason, regular season and postseason contact practices for the majority of position groups.

“The Guardian Cap has been a very important change for us as it’s shown to reduce impact. It has been very effective and reduced concussions by 52%.” stated Roger Goodell, NFL Commissioner, when discussing the results of the 2022 NFL season.

The NFL has reported concussions for players wearing Guardian Caps during the 2023 preseason were down 46% compared to their three-year average.

“That’s basically two preseasons in a row where we’ve seen that magnitude of a drop, suggesting that the success we saw last year in the preseason wasn’t just an aberration – it was actually sustained again this year.” said Dr. Allen Sills, NFL Chief Medical Officer.

Guardian Caps are worn by 300+ colleges, 3000+ high schools, 750+ youth programs, all 32 NFL Teams, and all 9 CFL Teams. They continue to better protect athletes across the world.