Concussion in sport: how is it recognized, when is the athlete removed from play, and how should return to sport go?

What is concussion, and how is it recognized?

Concussion is a temporary impairment of brain function after a blow to the head, face, neck, or a body blow that suddenly shakes the head. Standard imaging (CT, MRI) typically shows no structural damage; the problem is functional. The critical point is this: loss of consciousness is seen in only a small portion of cases (about less than 10%). The inference "they didn't faint, so there's no concussion" is the most common and most dangerous mistake.

Findings that should raise suspicion:

• Headache, a "pressure in the head" sensation, dizziness, imbalance, nausea
• Slowed, "foggy" thinking; answering questions late; confusing the score/opponent
• Inability to remember before or after the event
• Blank staring, taking a wrong position on the field, unusual irritability or emotionality
• Lying motionless after the blow, getting up staggering, walking while holding on

"If in doubt, sit them out" and pitch-side assessment

The framework of the 6th International Conference on Concussion in Sport in Amsterdam (2022) places this principle at the center: an athlete with a suspected concussion is removed from play, not left alone, and does not return to the field that day. The standard tool developed for evaluation is SCAT6 (Sport Concussion Assessment Tool, 6th version; Child SCAT6 for ages 8–12). SCAT6 combines a symptom list, memory and attention questions (e.g. "Which venue are we at? Who won the last game?"), a balance test, and a neck examination. Three points are important to know:

1. SCAT6 is designed for use only by trained health professionals (physicians and health personnel trained in this area). If you are a coach, teacher, or parent, your tool is CRT6 (Concussion Recognition Tool, 6th version): it does not and cannot make a diagnosis; its sole purpose is to recognize a concussion and remove the athlete from play.
2. SCAT6 is a screening tool; it does not on its own make or rule out a diagnosis. A normal result does not prove there is no concussion; the clinical decision is the physician's.
3. Symptoms can appear or worsen within hours. For this reason, even if the initial evaluation is normal, the athlete should be monitored and re-evaluated the next day.

Emergency (red flag) findings — worsening headache, repeated vomiting, seizure, progressively clouding consciousness, neck pain, double vision, weakness/numbness in the arms-legs — are outside concussion management; they require immediate emergency care.

Why is same-day return absolutely forbidden?

The basic rationale of the ban is gathered under three headings:

1. Neurological impairment continues. The reaction speed, balance, and decision-making ability of an athlete who has had a concussion remain impaired for a while; even if they say "I'm fine," the brain is not yet working normally.
2. The risk of a new injury increases. Staying on the field with impaired reaction and balance raises the probability of both a new head blow and any musculoskeletal injury; a new blow received before full recovery worsens symptoms and prolongs recovery.
3. An accompanying structural injury can be missed. Symptoms can appear or worsen within hours; pictures such as a neck injury or intracranial bleeding can mimic a concussion at first. Removing the athlete from play and monitoring them is the guarantee that these pictures are not missed.

In addition, one more rare picture is mentioned: "second impact syndrome" — a rapid and widespread brain swelling suggested to develop after a second blow received while the symptoms of the first concussion persist. Almost all have been reported in children and young athletes and it can be fatal. To be honest, this syndrome is rare and its scientific framework (nosology) is debated — the number of published cases is small, and in some of them it has been questioned whether the mechanism was really a "second impact." This rare possibility additionally supports the cautious approach that is already valid for the reasons above.

Rest or movement? Where the evidence has changed

For years "complete rest in a dark room until symptoms fully resolve" was recommended. Current evidence does not support this; in fact, strict rest was shown in a randomized trial to be able to delay recovery. Today's approach:

• First 24–48 hours: relative rest. Daily-life activities are free; screen time can be limited in the first days; tasks that markedly increase symptoms are postponed.
• Afterward: light aerobic activity (brisk walking, stationary cycling) is started at a level that affects symptoms only mildly and briefly. Randomized controlled trials and a meta-analysis combining them showed that this kind of controlled exercise started in the first days speeds recovery and reduces the risk of prolonged symptoms exceeding a month.
• The rule is simple: symptoms may increase slightly during activity but should settle quickly; a marked flare indicates the dose is too high.

That is, in concussion movement is not a "risky luxury" but, when applied at the right dose, part of the treatment — while contact sport and activities carrying a fall/blow risk remain forbidden until full recovery.

Gradual return: first school, then sport

In children and adolescents the priority is return to school; return to full training should not come before the student completes a full return to school. Return to sport is six steps; each step is stayed at for at least 24 hours, and if symptoms flare markedly, one returns to the previous step:

The first three steps can progress even before symptoms fully resolve (with the mild-tolerance rule); to move to step 4 and beyond (4–6), symptoms and cognitive impairments must have fully resolved both at rest and with exertion. Unrestricted return to sport takes, in pooled data, an average of about 20 days; in everyday terms, most people return to sport within 2–4 weeks — with significant individual differences — and the great majority have returned within a month. Return is determined not by the calendar but by passing the steps without problems.

Why is more caution taken in children and adolescents?

• In children and adolescents recovery takes longer than in adults; in large emergency-department cohorts, symptoms exceeded 4 weeks in about a third of children.
• Second impact syndrome cases are almost entirely in this age group.
• School performance is a separate topic: lessons, exams, and screen load should be planned gradually; the school should be informed.
• For these reasons the threshold is kept lower in a child athlete: if in doubt, sit them out; don't return without seeing a physician.

Repeated concussions: what we know and don't know

The likelihood of an athlete who has had a concussion having another concussion increases; recovery can lengthen with repeated concussions, and symptoms can appear with progressively lighter blows. Long-term effects (memory problems, the chronic traumatic encephalopathy debate) are much discussed in public; here the honest framing is this: an association has been reported between intense exposure to repeated head blows and some long-term problems, but the strength of the cause-effect relationship, who is at risk, and the threshold level are not yet clear. This uncertainty is not a reason for indifference but, on the contrary, an additional rationale for managing every concussion properly. In an athlete with concussions recurring at short intervals, prolonged recoveries, or a decreasing blow threshold, the decision to end the season or change sport should be made individually with an experienced team; there is no universal "three-concussion rule" for this.

For clinicians

The Amsterdam 2022 (6th consensus) framework: CRT6 for recognition (pitch-side, non-health personnel), SCAT6/Child SCAT6 for evaluation (most valuable in the first 72 hours), SCOAT6 in the subacute period. Loss of consciousness, amnesia, and convulsive/tonic posturing are not automatic severity markers but are an indication for removal; cervical pathology and structural lesion should be ruled out with red flags (CT is not routine; in cases selected with clinical decision rules). In management the paradigm has shifted from "rest is best" to "exercise is medicine": after 24–48 hours of relative rest, sub-symptom-threshold aerobic exercise (Buffalo protocol logic; target heart rate can be determined with a symptom-limited bike/treadmill test) has, in RCTs and a meta-analysis, sped recovery and reduced the risk of persistent symptoms. In a prolonged case (>4 weeks), a targeted evaluation is recommended instead of a one-size "extend the rest": separating the cervical, vestibular-oculomotor, autonomic/exercise-intolerance, and mood components, and if needed vestibular rehabilitation and a gradual aerobic program. In predicting the risk of persistent symptoms, the 5P clinical risk score (Zemek et al.) has been validated in the pediatric emergency department. The nosology of second impact syndrome is debated (McCrory-Berkovic criteria; Cantu-Gean's emphasis on a thin subdural hematoma), but the ban on same-day return and the ban on contact before full recovery are common to all guidelines. There is no validated threshold for a retirement/discontinuation decision; a multidisciplinary decision is recommended based on concussion frequency, a decreasing threshold, prolonged recovery, neurological residua, and athlete preference.

Frequently asked questions

Related articles

• Sudden cardiac death in athletes and preparticipation screening: what to know
• The child and young athlete: early specialization, growth-phase injuries, and safe sport
• Return to sport after injury: not the calendar, but the tests

Scientific references

This information is for general guidance only; it does not replace an examination, a diagnosis, or your physician's individual advice. Please consult a physician for your symptoms. About the author: Doç. Dr. Oğuz Yüksel — Academic Profile.