Common Sports Injuries
Sprain or strain? Acute or overuse?
Most injuries an athletic trainer sees on a given afternoon come from a short list. Knowing the categories tells you what tissue is hurt, how long it takes, and what to watch for.
The big idea
Sprain = ligament. Strain = muscle or tendon. If you remember nothing else from this page, remember that.
Acute versus overuse
An acute injury has a moment: a landing, a collision, a cut that went wrong. Someone can usually tell you the exact play it happened on.
An overuse (chronic) injury has no moment. It builds from repeated submaximal loading without enough recovery — shin splints, tendinopathy, stress fractures. Athletes often push through the early phase because there is no dramatic event to point at, which is exactly why overuse injuries end up sidelining people longer.
Sprains: ligament injuries
A sprain is a stretch or tear of a ligament, and it is graded by severity.
The lateral ankle sprain is the most common injury in sport, and it almost always happens through inversion — the foot rolling inward under the leg — which stresses the ligaments on the outside of the ankle, most often the anterior talofibular ligament.
- Grade I
- Mild. Ligament fibers stretched, minimal tearing. Mild pain and swelling, joint still stable, usually a short recovery.
- Grade II
- Moderate. Partial tear. Noticeable swelling and bruising, some joint laxity, weeks of rehabilitation.
- Grade III
- Severe. Complete tear. Significant instability. Often requires imaging, sometimes surgery, and a long return-to-play timeline.
Strains: muscle and tendon injuries
A strain is a stretch or tear of a muscle or tendon. Hamstring strains are the classic example in sprinting sports, and they typically happen during the late swing phase of a stride when the hamstring is lengthening under high tension — an eccentric contraction.
Strains are graded on the same I-to-III scale. A grade III strain can involve a complete rupture, sometimes with a visible defect or a bunched-up muscle belly.
Bone and soft-tissue injuries worth naming
A fracture is a break in a bone. Signs that push suspicion toward a fracture include deformity, point tenderness directly over bone, inability to bear weight, and a crunching feeling called crepitus. An open fracture, where bone has broken through skin, is a medical emergency because of infection risk.
A contusion is a bruise — direct-impact bleeding within muscle. A dislocation is a joint whose bones have been fully separated from their normal alignment; a subluxation is a partial one that often relocates on its own.
A stress fracture deserves its own mention. It is an overuse injury: microscopic damage accumulating faster than bone can rebuild. It hurts during activity, eases with rest, and comes right back — and it will not show on an early X-ray, which is why the athlete who "keeps getting a sore shin" needs to be taken seriously.
See it in the book
These pages of the Sports Medicine Coloring Book draw out what you just read. Tap any one to look closer.
Terms from this lesson
- Sprain
- Injury to a ligament.
- Strain
- Injury to a muscle or tendon.
- Crepitus
- A grating or crackling sensation from bone ends or inflamed tissue.
- Point tenderness
- Pain isolated to one specific spot on palpation — a fracture warning sign.
- Eccentric contraction
- A muscle producing force while lengthening. Common in strain mechanisms and central to prevention programs.
- Tendinopathy
- Pain and dysfunction in a tendon from chronic overload.
Check yourself
Answer out loud before you open the card. Recall is what makes it stick.
Classroom activity
Case-card triage
Write ten short scenarios on index cards — mechanism, symptoms, and what the athlete says. Students sort them into sprain, strain, fracture, contusion, or overuse, then justify the call using the mechanism rather than the location. The point of disagreement is the lesson: two injuries in the same spot can be entirely different tissues.