Good timing for me to respond here.
We just had a sports oriented Physical Therapist come out to the last 30 minutes of our practice on Tuesday. I'm no expert, so I'll try to recall here what she said.
There are 3 main types of injury:
1. Trauma - Caused by a collision or a twist.
2. Overuse - Caused by not resting enough, playing too much.
3. Dings, bruises - Everyday, normal things that happen when playing sports.
And a 4th - Growing pains. These occur when the bones lengthen faster than the muscle. Usually a bilateral pain and you can't trace it back to something from items 1-3.
Leg injuries are interconnected throughout the entire leg. A knee injury may be the result of a muscle imbalance between the hips, quads, hamstrings and ankle.
A sharp pain that increases with movement is something to have looked at. If you ask your player if they feel like they are being stabbed, that's a sharp, shooting pain. Limping for more than a few minutes after the injury happens should be treated with caution. Any swelling should be treated with caution and should be looked at.
Dull pain is not as big of a worry. But if it lasts for 10+ days, it's worth taking a look.
At around the age of 11, athletes should start to incorporate some strengthening and stretching into their routine. Weights are not needed for strength. Body weight exercises like push ups, squats, lunges are great. There are a lot of variations of each of these exercises (traditional, side, rear, single leg, etc). Also, using resistance bands to strengthen hips is recommended. Proper form is THE MOST IMPORTANT aspect of these types of exercises for young athletes. Young females tend to buckle their knees when doing squat exercises. Or when doing a lunge, their front and back leg are in terrible positions. Make sure to strengthen all interconnected muscle. As mentioned above, muscle imbalances can be a root cause of many types of injuries.
This series of exercises seems to be the recommendation for prevention of lower extremity injuries for athletes. Try to have your player do it 3 or more times per week.
http://www.uwhealth.org/sports-medi...ucation-acl-injury-prevention-exercises/42908
My team does it a lot during pre and early season. We really should do it with every practice. (The team is 04 and 05 players - 11 and 12 year old girls. The first time they did it, they were extremely sore in muscles they had not worked very much).
Proper running form is also very important. And in soccer, we run forward, backward, sideways, shuffle, change of direction.
Flexibility is often overlooked. Tight muscles also lead to imbalances or compensating my using other body parts. The physical therapist HIGHLY recommended a foam roller routine every day. Google "foam roller" workout for ideas for quads, calves, hips, hamstrings.
Proper footwear was also discussed - She recommended making sure you are in the correct cleat size. Apparently at the pro levels of soccer, many players wear a shoes 1/2 to a full size smaller. This is not recommended as it puts added pressure on the tiny bones of the feet. She recommended walking barefoot whenever you are in a safe area (IE- not glass, rocks, sticks, insects, etc). Let the feet splay out is good for them to get strong. This is why slides are a good idea to put on after a soccer activity.
Fatigue can have a big impact on injuries. Tired minds make bad decisions. Tired bodies are not positioned properly. A tired mind and a tired body are a bad combination. I've personally seen a physical therapist for a lot of lower leg and back issues. I used to do a lot of running. I really had to work to get my muscles in proper balance. And I had to consciously keep my form in check if I wanted to run a long distance. Because you can get away with crappy form for 3-6 miles. After that, if you have bad form, then it gets worse. My right knee would dip in and cause me a ton of hip pain. The knee dipping in was a result of improper foot alignment.
We also asked her where to go first if you think there is an injury - Doctor or Physical Therapist. If there is trauma, see a doctor for x-rays and diagnosis. If it's just pain from overuse and nothing appears "broken" you could see a PT first or a doctor. A lot of the decision will also come down to how your insurance works. Some companies require a referral to see a PT.
See if your club can get a PT or sports doctor to come out and talk to your team. I think it was a good use of 30 minutes.