In the fourth T20I between India and England on January 31, 2025, Jamie Overton’s delivery struck Shivam Dube on the helmet during the 19th over. Following a mandatory concussion assessment, Dube continued to bat, but was run out on the next delivery, possibly due to impaired judgment stemming from the impact. Subsequently, India introduced Harshit Rana as a concussion substitute for Dube, a move that sparked debate over the appropriateness of the replacement.
Cricket was considered a safe sport largely, until Phil Hughes tragic death in 2014 highlighted possible risks. Despite wearing a helmet, the Australian cricketer suffered a fatal vertebral artery dissection from a short-pitched delivery. This led the ICC to enhance player safety, introducing redesigned helmets with extended guards and mandating wicketkeepers to wear helmets while standing up to spinners. In 2019, concussion protocols were implemented, requiring mandatory medical evaluations for any player injured before resuming play.
What is a Concussion?
A concussion is a mild traumatic brain injury caused by a sudden hit, jolt, or impact on the head or body, leading to rapid movement of the brain inside the skull. This shaking disrupts normal brain function, resulting in temporary neurological dysfunction without necessarily causing structural damage visible on imaging. Though often mild, concussions require proper care to prevent long-term complications. Concussions occur due to the rapid acceleration and deceleration of the brain inside the skull. It is a functional brain injury resulting in an energy deficit from biomechanical force.
The brain is a jelly-like delicate organ sitting inside the rigid skull and cushioned by cerebrospinal fluid. It comprises grey matter (neuronal cell bodies) and white matter (nerve fibres or axons). During rapid acceleration or deceleration—such as when a fast-moving ball strikes a cricketer—the brain can move back & forth within the skull. This movement may lead to a disruption in normal brain activity.
When a force hits the head, the brain is shaken, stretching the delicate axons that connect neurons. These axons aren’t just wires—they make us conscious, think and perceive the world. When they stretch, potassium ions leak out, triggering uncontrolled electrical firing across the brain. This misfiring is why concussed players experience dizziness, confusion or flashes of light.
If the stretching is too much, the axon breaks, releasing tau protein, a substance linked to chronic brain diseases. Over time, repeated concussions or even minor undiagnosed hits lead to tau buildup, causing chronic traumatic encephalopathy (CTE), personality changes, anxiety, depression, and dementia. Cricket may not be as violent, but fast bowlers hurling 140 km/h deliveries at close-range batsmen create a significant risk.
Causes and symptoms
Concussions occur due to two primary forces—linear and rotational acceleration—which impact the brain during sudden acceleration and deceleration. These forces are measured using accelerometers placed in athletes’ helmets or mouthguards. A concussion typically happens between 70-120Gs of linear acceleration and 5500-9500 rad/s² of rotational acceleration. Children sustain concussions at 62Gs, while adults require 98Gs due to stronger necks. Severe brain injuries occur at 316Gs, often seen in car accidents. In cricket, a 156-gram ball bowled at 80 miles per hour, hitting the batsman for less than 3 milliseconds, can generate enough force to induce a concussion, even if it hits a protected area.
A concussion is diagnosed when an individual experiences a head injury due to an external force, such as a blow to the head or a sudden jolt, accompanied by at least one of the following 22 symptoms: headache, dizziness, nausea, vomiting, balance problems, blurred vision, sensitivity to light, sensitivity to noise, feeling sluggish, feeling foggy, difficulty concentrating, memory problems, confusion, feeling more emotional, irritability, sadness, nervousness, anxiety, sleep disturbances, difficulty falling asleep, sleeping more than usual, or sleeping less than normal. Even the presence of a single symptom associated with an injury can be indicative of a concussion and warrants immediate medical evaluation. Concussion symptoms can appear immediately or be delayed for hours or days. Symptoms typically last 7 to 14 days, but in some cases, they can persist for weeks or even months, especially if not properly managed, requiring medical evaluation
Former cricketer Kris Srikkanth recently suggested on his YouTube channel that concussions should be treated like any other injury. But concussions are indeed a unique type of injury. A concussion is a functional injury, not a structural one. The damage isn’t visible on MRI or CT scans because the problem isn’t in the brain’s structure but in its function. It’s an energy deficit—a temporary breakdown in the brain’s electrical system due to rapid acceleration and deceleration inside the skull.
Unlike a broken bone that forces a player to stop, a concussed player might seem fine after a few minutes of dizziness and blackout. This is what makes it dangerous. The brain is still struggling to reset, but the player, unaware of the risk, might push through. Cricket is competitive, and the temptation to keep going is high. Hence, protecting a concussed player’s health rests on the sporting authorities, who must intervene. That’s why a concussed player is replaced—not just for fairness in the game, but for their survival.
While cricket has recently intensified its focus on concussion management, other contact sports have long recognized the risks associated with head injuries. Ice hockey was among the first to introduce concussion substitutes in 1997. In football (soccer), studies have shown that concussions are more often the result of player-to-player contact rather than heading the ball itself. Other sports have seen the consequences—American football, boxing, and rugby have long dealt with CTE cases.
Long-Term Implications
Repeated concussions can have cumulative effects, leading to long-term neurological issues like CTE. The potential for such severe outcomes highlights the importance of strict adherence to concussion management protocols and the necessity of adequate rest and recovery periods. It’s beyond my scope to interpret whether Shivam Dube’s replacement was a true like-for-like substitute. While the specifics of his medical evaluation are not publicly disclosed, returning to play soon after a concussion is generally not advisable. Medical guidelines recommend a gradual return to activity to ensure full recovery and minimise the risk of further injury. In conclusion, concussions are complex injuries that require careful management, keeping the athletes long-term health in mind beyond his playing days.
(Dr. C. Aravinda is an academic and public health physician. The views expressed are personal. aravindaaiimsjr10@hotmail.com)
Published – February 10, 2025 10:08 pm IST
