Games such aa American football pose a particularly high risk for injuries that can have devastating long-term consequences for individuals.
Nicholas Cecchi, a PhD candidate at Stanford University and lead author of the study, said: "Concussion and repeated head impacts are still a major problem in contact sports and we believe that improved helmet technology can play an important role in reducing the risk of brain injury."
The team built a finite element model, used by engineers to simulate performance before manufacturing, of an American football helmet incorporating 21 liquid shock absorbers.
This helmet was tested against simulations of the helmet performance evaluation protocol used by the National Football League (NFL) and its performance was compared to that of four existing helmets.
Due to the mounting evidence that the cumulative effect of impacts which don't cause diagnosed concussions can also have serious health consequences, the team added lower velocity impacts to their evaluation of the helmet.
They measured the head kinematics for each impact to produce a score, which is used to evaluate helmet performance under impact. The data was also fed into a model of the head and brain to gauge the resulting strain on the brain.
The results showed that the helmet with liquid shock absorbers could dramatically reduce impact severity and strain on the brain caused by head impacts, potentially cutting injuries significantly.
The helmet with liquid shock absorbers performed better than the existing helmet models and was best at protecting the dummy head in 33 out of the 36 different impact conditions tested.
The liquid helmet also had the best 'Helmet Performance Score', a measure used in the NFL's annual helmet safety rankings, which includes a weighting for how well a helmet protects against blows in different areas of the head.
The highest-weighted location is the 'side upper' portion of the helmet because impacts here are most likely to cause concussions. The helmet with liquid shock absorbers reduced impacts in this area by 39-50 per cent across all velocities without compromising protection in other areas of the helmet.
"The liquid technology offered an average improvement of over 30 per cent for both low and high velocities," said Dr Yuzhe Liu, corresponding author. "It can dramatically reduce the loading on the brain that is experienced during all kinds of American football impacts."
The team intends to develop the model significantly to protect players better – for instance, by incorporating improvements to the facemask and chinstrap. They also plan to develop the model into a physical helmet that could be tested in real-life conditions, and in the future to produce similar helmets for other sports.
