1. Introduction

CTE, known as the chronic traumatic encephalopathy, is a progressive degenerative disease that is affecting people who suffered from repetitive concussions and traumatic brain injuries [1]. This symptom is most likely to happen to athletes that is exposed to sports with high concussions and head injuries.

While CTE is a specialized neurodegenerative disease which brought about repeated head trauma, punch syndrome is another specific branch of CTE. This term was primarily applied in 1928[2] to describe the brain trauma mostly experienced by boxers. Punch drunk syndrome can be considered as a brain disease that has a high occurrence rate to athletes who are in for sports that involve frequent body contact and faces potential risk of receiving head concussions. It has the highest occurrence rate in sports such as boxing and martial arts (or mixed martial arts). It also occurs to football and ice hockey players even if their helmets are on.

The comparison of the occurrence rate of CTE in different contact sports (for athletes only) is as follow.

Table 1: Prevalence of CTE in Different Contact Sports.

CTE is most seen in sports with high-impact collisions, particularly in American football, boxing, and ice hockey, where repetitive head trauma happened at a higher rate. Even though soccer and martial arts were safer from CTE, risks are not something that can be ignored, especially with frequent or significant impacts. The overall trend represents that there is a positive relationship between the longevity of an athlete’s career and the head impact they experience as well as the likelihood of developing CTE [3].

As research continues, more data will be required to give out the overall assessment of the long-term effects of contact sports, especially with recent improvements in concussion protocols and awareness of head injury risks.

2. Physiological Reactions

Repeated punches to the head can cause temporary or lasting disruption in brain function, leading to symptoms such as confusion, dizziness, headache, and nausea.

Repeated head trauma can lead to chronic neuroinflammation, where the brain's immune cells (microglia) become activated in response to injury. This chronic inflammation can contribute to long-term brain damage and is thought to be involved in the development of neurodegenerative conditions like CTE (Chronic Traumatic Encephalopathy).

Over time, repeated head injuries can result in cognitive decline, including memory loss, difficulty concentrating, and slowed processing speed. These issues are a hallmark of brain damage due to repeated trauma, and they can worsen as the cumulative effects of punches accumulate.

3. Effects of both long-term and short-term

In contrast to mild punch syndrome, or concussion, which causes functional disturbance and axonal injury rather than gross structural brain damage, punch CTE's short-term sequelae include subdural hemorrhage and catastrophic brain injury, which can be fatal [4]. Following a concussion, symptoms like headache, dizziness, nausea, attention loss, and amnesia tend to develop acutely but usually go away in two weeks. Severe concussion can also result in loss of consciousness and mental health.

The neurodegenerative process of CTE linked to tau hyperphosphorylation—an excessive rise in the number of phosphate groups added to the tau protein—may be caused by acute punch syndrome. Under typical circumstances, it helps to stabilize microtubules, which are vital elements of the internal structure of the cell. Nevertheless, tau may lose its capacity to connect to microtubules when it becomes phosphorylated, and the formation of neurofibrillary tangles (NFTs) is still up for debate. The predilection of CTE-tau pathology for perivascular and subcortical regions, along with the presence of focal tau-positive NFTs and neurites near focal axonal injury and foci of microhemorrhage, indicate that the mechanistic link between punch syndrome and CTE is likely to be based on acute TBI-related axonal injury, loss of microvascular integrity, breach of the blood brain barrier, ensuing inflammatory cascade, and microglia and astrocyte activation.

Punch syndrome implications have been documented for their long-term effects since the early 1900s. When boxers encountered clinical disorders, terms like dementia pugilistica and punch drunk were first employed to characterize them. Chronic traumatic encephalopathy (CTE), a more general term, has been used since the middle of the 20th century to refer to a neurodegenerative condition that has been identified in boxers as well as American football players, athletes who play contact sports, veterans of the armed forces, and others who have experienced repeated brain trauma, such as concussions and sub concussive trauma. Among the clinical characteristics are deficiencies in mood (such as sadness and hopelessness), behavior (such as aggression and violence), cognition (such as dementia, executive functioning, memory, and attention), and, less frequently, motor functioning. (for example, parkinsonism, ataxia, and dysarthria) [5].

4. Diagnoses

The main symptoms of punch syndrome include mood disorders, which summarizes the behavior of depression, apathy (a state of diminished motivation, interest, or emotional responsiveness, often linked to dysfunction in specific brain regions), emotional instability, substance misuse, and suicidal thoughts or behavior. It also leads to cognition issues, in the form of difficulty thinking (cognitive impairment), memory loss, problems with planning and executing tasks (executive function). In addition, behavioral problems can also be shown as impulsive behavior and aggression [6].

The diagnosis of Boxing Syndrome typically relies on medical history, clinical symptoms, and imaging studies. Common imaging studies include Computed Tomography (CT)scans and Magnetic Resonance Imaging (MRI) [7]. CT scans can reveal abnormalities in brain structure, while MRI provides more detailed information about the soft tissues of the brain, helping to identify the extent and location of brain injuries.

5. Prevention and intervention

Preventing chronic traumatic encephalopathy (CTE) in athletes involves a comprehensive approach that includes limiting head impacts, enhancing protective gear, and implementing rigorous injury management protocols [8]. Limiting the number of times athletes are hit on the head is crucial and can be achieved through better equipment, medical procedures, education, and rule improvements. High-risk behaviors can be reduced by enforcing fines for dangerous movements, limiting contact during training, and maintaining controlled rest schedules following suspected concussions. Regular equipment checks and the use of reliable protective gear, such as force-buffered helmets and sensor-equipped mouthguards, are essential. Training for both athletes and coaches on safe practices, injury response, and the importance of reporting symptoms is crucial, especially for young athletes who can develop safety-first behaviors early on.

Effective injury management involves rigorous concussion protocols, baseline cognitive testing, and the presence of on-site medical personnel. Technologies like video playback and impact monitoring systems can identify potential dangers and hazards that might lead to CTE. Monitoring the strength of hits received on the head is vital for precise assessment and injury prevention. Modern helmets and mouthguards equipped with impact sensors measure forces such as acceleration, rotation, and hit frequency. These devices provide real-time data to coaches, medical personnel, and athletes, alerting them to potentially hazardous levels. High-speed cameras and video processing enable post-play evaluations of collisions and their severity.

Athletes' brain function is measured using simple cognitive tests before the season, which can be compared after an impact to detect injuries. Cumulative tracking systems compile data over time to identify patterns of recurring exposure. Consistent monitoring is ensured using wearable technology during practices and games. These measures, along with mandatory concussion procedures and prompt medical assessments, facilitate early intervention and reduce the risk of long-term harm from head injuries [8].

It is crucial to remain aware of long-term risks while maintaining the spirit of competitiveness. Ongoing research and innovations will help ensure athletes' performance and their physical and mental health. By using technologies like video playback and impact monitoring systems, it is possible to identify the potential dangers and hazards that might result in CTE. Further research and innovations will guarantee athletes' performance as well as their physical and mental health.

For the prevention of CTE in everyday life, suggestions are as follow:

Avoid direct head collisions: In daily life, it is important to protect the head from direct impact or collision from external objects, especially during high-risk activities such as riding motorcycles, climbing, skiing, etc. You can wear helmets or protective gear to protect your head.

Pay attention to traffic safety: When traveling in traffic, follow traffic rules, pay attention to passing vehicles, and avoid traffic accidents that can cause impact and injury to the brain.

Maintain a regulated sleep schedule: Avoid prolonged mental stress, ensure appropriate amount of sleep at night, and develop regular sleep habits. This is beneficial for the body to recover energy, improve immunity, and reduce the probability of injury.

Regular physical examination: It is strongly advised to undergo a detailed physical examination at least once a year to detect potential health problems early and take timely measures for intervention.

6. Case study in boxing

The long-term effects of head trauma in sports that involves high contacts, particularly boxing, imposes a deadly threat on both the physical and mental well-being of athletes [9].

Muhammad Ali, who was known to be a legendary boxer in human history, played the role of a striking example of these challenges. Repetitive blows to the head during his illustrious career worsen the result of his neurological circumstance in the last few years of his career life. Head trauma in boxing is often linked to progressive neurological diseases, including Parkinson's disease and chronic traumatic encephalopathy (CTE). Although Ali was diagnosed with Parkinson's disease in the 1980s, his symptoms—such as memory loss, tremors, and cognitive decline—have a close connection of those of CTE, a condition commonly relevant to repetitive brain injuries. This suggests that the damage Ali sustained throughout his career may have played a significant role in his deteriorating health.

Ali’s case highlights the growing concern surrounding the long-term effects of repeated head injuries in contact sports, particularly boxing. The physical and mental toll these athletes endure often remains hidden until years after their careers have ended, making early detection and prevention a challenge. Moreover, the difficulty in distinguishing between diseases like Parkinson's and CTE adds complexity to diagnosis and treatment, leaving many athletes in a vulnerable position. Ali’s situation also raises critical ethical questions: Should athletes be better informed about the potential risks of their sport? What responsibility do governing bodies have in implementing stricter safety measures? From mandatory medical screenings to improved protective equipment, much needs to be done to mitigate the risks without diminishing the sport's competitive spirit. Ali’s story serves as a stark reminder of the potential cost of prioritizing victory and legacy over long-term health.

Ali's miraculous career spanned decades and included iconic fights like the "Rumble in the Jungle" and the "Thrilla in Manila," where he endured countless powerful punches to the head. These fights, celebrated for their drama and intensity, were also taxing on Ali's physical condition, particularly in his later years when he continued to face younger, stronger opponents. His decision to keep boxing despite the physical toll exacerbated the damage, highlighting the risks athletes face when pushing their limits in high-impact sports.

The case of Muhammad Ali underscores the importance of addressing the long-term health consequences of head trauma in sports. It raises awareness of the need for better protective measures, early diagnosis, and support for athletes who suffer from these conditions after their careers end.

Some statistics of punches with forces are as follow, aiming at giving a clearer understanding of Muhammad Ali’s case above. Amateur boxers deliver punches with forces around 2,500 Newtons (N) [10]. Professional boxers have been recorded delivering punches with mean forces ranging from 866.6 N (Super Featherweight) to 1,314.7 N (Middleweight) [11], Peak punch forces can reach up to 4,096 N, attained within fourteen milliseconds of contact [12].

Head injuries account for 74% to 96% of total injuries in boxing, with concussions responsible for up to 75% of these head injuries. Approximately 90% of boxers will suffer a concussion at some point in their careers. At least 15% of retired professional boxers live with chronic brain injury, including conditions like chronic traumatic encephalopathy (CTE).

7. Conclusion

A better knowledge of the long-term effects of brain trauma in contact sports is urgently needed, as evidenced by the Muhammad Ali case and the larger research into punch syndrome and chronic traumatic encephalopathy (CTE). The signs of Ali's Parkinson's disease, which are strikingly like those of CTE, highlight the hidden risks that athletes who are repeatedly hit in the head confront. In addition to boxing, participants in other high-contact sports including American football, ice hockey, and rugby are also susceptible to neurodegenerative diseases because of repeated brain trauma.

The intricacy of punch syndrome and CTE is highlighted by the physiological processes that underlie both disorders, including neuroinflammation, tau hyperphosphorylation, and neurofibrillary tangles. To reduce injuries to athletes, these findings not only emphasize the need for more thorough study into early diagnosis methods but also demand better safety equipment, stronger laws, and medical oversight. Stricter guidelines for head impact exposure during sport and training, for instance, may lower the risk of CTE. Furthermore, early detection and management of brain injuries depend on educating players, coaches, and medical professionals about their symptoms and long-term effects.

In addition, Muhammad Ali's legacy serves as a warning about the physical costs associated with long-term success in high-impact sports. Although his career served as an inspiration to millions, it also highlights the need of putting athlete safety first so that next generations of athletes may follow their hobbies without endangering their long-term health. Sports organizations and medical researchers must collaborate as our understanding of CTE advances to create strategies that strike a balance between athletes' well-being and competitive performance, addressing the risks without compromising the spirit of these cherished sports.