This injury can at times be very easy to spot and at times very difficult to spot. In my experience two players facing the same time of incident will respond very differently. One may walk away with no injury and one may be out for a month. So, I have found it is very, very important to treat each incident and player uniquely. the video and other literature will describe symptoms and this is important. But, what I have learned is, nearly any behavior out of the norm for that player can be attributed to brain injury and it can show up days after the incident. For example, if a player has a head on head blow on the field and shows no signs during or after the game it is possible signs may show up a day or so later. For example, she may go to school and have a hard time reading what is written on the board. She may have headaches or dizziness. In short, if the player is acting abnormally after an incident that could have resulted in a concussion it is safest to approach it as a possible concussion. In short, the number one treatment for a suspected concussion is rest. Rest the brain. If you suspect it is a concussion head to the doctor and get it checked out. We will of course follow the physician's advice on when to return to play.
In my experience, sprained ankles are possibly the number one injury in soccer. Nearly every player who has played soccer for more than a few years has encountered an ankle sprain. Most are minor and will heal quickly. Some can be incredibly painful and take months to recover from. With that said, most require a little rest and self-treatment. This link takes you to the Mayo Clinic's Sprained Ankle pages. Below is the video from the Mayo Clinic that shows the explanation of what most sprained ankles are.