How do i know a sports injury isnt something i can just walk off?

Try walking on it: Most sports related injuries are mild enough that formal medical attention is not necessary. Pain with routine use is a predictable symptom that should alarm individuals to seek medical attention for at least an informed opinion and an injury specific examination. If no pain, obvious deformity, skin break, or sense of joint looseness (laxity) is present, an attempt at "return to play" is safe.

Red flags: Associated symptoms, severity of pain, and persistence of symptoms are clues. Red flag symptoms include significant swelling, instability , difficulty bearing weight or decreased range of motion. Sharp pain with movement or weight bearing or worsening pain are not good signs. If symptoms are not improving within 48 hours especially if using ice, NSAID , rest, then seek medical care.

Need evaluation: If you have pain (lower extremity injury) while walking then diagnostic testing may be necessary (i.e. X-rays, mri) to rule out a fracture or a ligament, meniscus or tendon/muscle tear. A thorough musculoskeletal examination is appropriate in this scenario.