How Smart Mouthguards and Belly Tackles Are Saving Rugby

For years, rugby union has wrestled with an existential crisis: how to preserve the ferocious, high-impact collisions that define the sport while protecting the brains of the athletes who play it. Rising concussion rates and early-onset dementia diagnoses among retired professionals forced a reckoning. Now, the sport is undergoing a radical transformation driven by a two-pronged approach: cutting-edge wearable technology and fundamental behavioral changes to the rules of engagement.[1][3]

At the elite level, the focus is on objective diagnostics. World Rugby has mandated the use of instrumented mouthguards (iMGs) across all top-tier competitions, investing millions to equip thousands of players with sensor-embedded protective gear. Simultaneously, at the community level, the governing body has initiated a global shift in how the game is physically played, lowering the legal tackle height to the base of the sternum.[1][5]

Together, these initiatives represent one of the most aggressive player welfare interventions in modern sports history. Early data from the 2025 and 2026 seasons suggests the strategy is working, fundamentally altering tackling mechanics and removing the guesswork from concussion protocols.[2][6]

The technological centerpiece of this revolution is the smart mouthguard. Developed by Prevent Biometrics and manufactured by OPRO, these custom-fitted devices contain a low-profile battery, a circuit board, a Bluetooth antenna, and triaxial accelerometers and gyroscopes. Because the upper jaw is rigidly attached to the skull, a mouthguard provides the most accurate proxy for brain movement during a collision, far outperforming sensors placed in helmets or headbands.[4][5]

The mouthguards continuously measure Head Acceleration Events (HAEs)—the rapid changes in linear and angular velocity that occur when a player takes a direct blow to the head or a heavy impact to the body. Since their mandatory introduction in January 2024, the devices have recorded over 150,000 head acceleration events across men's and women's rugby, creating what World Rugby's medical officials describe as the most comprehensive head-impact database in sports science.[8]

When an impact exceeds a specific threshold, the mouthguard transmits an instant Bluetooth alert to the independent Match Day Doctor on the sideline. The doctor then reviews the video footage and can mandate that the player be removed from the field for a formal Head Injury Assessment (HIA). This objective data removes the reliance on observable symptoms, catching concussions that players might try to hide or that medics might miss in the chaos of a match.[5][8]

In 2025, the technology received a highly visible upgrade: LED lights. Trialed first in North America's Major League Rugby, the newest iteration of the smart mouthguard features an embedded LED that flashes bright red when a severe impact threshold is breached.[7]

The flashing mouthguards made their global debut at the 2025 Women's Rugby World Cup and have since rolled out across elite men's competitions in 2026. For the women's game, the threshold is set at 65G of linear acceleration and 4,500 radians per second squared of angular acceleration. When a collision hits that mark, the mouthguard immediately flashes, providing an unmistakable visual cue to the referee, players, and medical staff.[3][4][6]

The speed of this intervention is critical. Medical research indicates that continuing to play for even 15 minutes after sustaining a concussion can compound neuropathophysiological damage and prolong recovery by weeks. By instantly stopping play when the red light flashes, referees ensure the athlete is removed from the compounding danger of subsequent rucks and tackles.[3][4][7]

While technology manages the impacts that do happen, World Rugby's rule changes aim to prevent them from occurring in the first place. Rigorous independent research revealed that the tackle is responsible for 74 percent of all concussions in the sport. Furthermore, tackles where the tackler's head is positioned above the ball carrier's sternum are four times more likely to result in a head injury.[1]

In response, World Rugby launched an opt-in global trial in 2023, urging national unions to lower the legal tackle height in community rugby from the shoulder line to the base of the sternum—often referred to as the "belly tackle." The goal was to force players to bend at the waist, moving their heads out of the high-risk zone where skull-to-skull and skull-to-shoulder collisions frequently occur.[1]

The transition required a massive re-education effort. Coaches had to retrain muscle memory, teaching players to dip into contact and target the softer midsection. Unions across England, Scotland, Ireland, Australia, and South Africa adopted the trials, fundamentally changing the geometry of the grassroots game.[1]

The empirical results are now validating the disruption. In April 2025, the University of Edinburgh published the first peer-reviewed study evaluating the lowered tackle height in Scottish men's community rugby. By analyzing video of over 18,000 tackles, researchers found that the new laws were linked to a staggering 45 percent reduction in head-on-head contact.[2]

The study also recorded a 29 percent reduction in head-to-shoulder contact for both the tackler and the ball carrier. Crucially, the data proved that behavioral change was taking root: players were 22 percent more likely to enter the tackle bent at the waist. The intervention successfully altered tackling behavior exactly as biomechanists had intended.[2]

Despite the promising data, the transition has not been entirely frictionless. The introduction of the LED mouthguards requires a cultural adjustment; players and coaches must learn to trust the sensor's data even when an athlete feels fine and displays no visible signs of distress. In the community game, the lowered tackle height initially led to a spike in penalties as players struggled to adapt their technique under fatigue.[2][3]

Yet, the consensus among medical professionals and administrators is that these growing pains are a necessary price for the sport's survival. By combining the objective surveillance of smart mouthguards with the structural safety of the belly tackle, rugby is building a comprehensive shield against its greatest threat, ensuring the game remains both fiercely physical and fundamentally safe for the next generation.[1][6]