However, the 2008 meeting in Zurich abandoned the simple versus complex terminology, although the participants did agree to keep the concept that most (80–90%) concussions resolve in a short period (7–10 days) and although the recovery time frame may be longer in children and adolescents.In the past, the decision to allow athletes to return to participation was frequently based on the grade of concussion. However, current research and recommendations by professional organizations including the National Athletic Trainers Association recommend against such use of these grading systems. Currently, injured athletes are prohibited from returning to play before they are symptom-free during both rest and exertion and until results of the neuropsychological tests have returned to pre-injury levels.Three grading systems have been most widely followed: by Robert Cantu, the Colorado Medical Society, and the American Academy of Neurology. Each employs three grades, as summarized in the following table:

See also
Concussions in American football
Concussion in Rugby Union
Head injury criterion
Helmet removal (sports)

References
External links

"Facts about Concussion and Brain Injury and Where to Get Help" US Centers for Disease Control and Prevention
"Concussion in High School Sports" US Centers for Disease Control and Prevention
2018 CDC Guideline on MTBI in children
This "instant delivery" problem causes many OBGYN doctors to stress the importance of women with a huge pelvis practicing pre-delivery vaginal stretching to avoid perineal injury. Such a large size for the female pelvis is present in less than one in a thousand adult women. When women reach their maximum pelvis size, often by 21 years of age, if they have a huge pelvis the resulting big hips will not go away—no matter how much they diet, as bone will not shrink. It is not unusual for such women, whose pear shape is due to a huge pelvis, to give up watching calories for smaller hips... leading to obesity. However, such pear shaped obese women do not necessarily have a huge pelvis and a measurement scan or anthropometry by calipers is required to diagnose the Justo Major condition. The incidence of Justo Major Pelvis is not found to be a strictly standard deviation type variation as it follows a tail skewed deviation to the right. Incidence varies with geographic regions of the world (e.g. Poland has a high incidence). Justo Major Pelvis is classified as congenital and thought to be partially inherited, especially from the maternal side. == References ==