A good read is Warrior Girls. Just finished this book which is about girls and sports injuries. While the author tends to focus alot on soccer and related injuries there it has alot of interesting info. Girls are also more prone to concussions than boys.
Thanks for pointing out the interesting video clip.
A few points on ACL injuries:
Caine noted that gymnastics injuries most commonly affect the lower extremity; a comparison of data from 14 studies cited by Caine suggests that knee injuries are (almost?) as frequent as ankle injuries in gymnastics. [Caine DJ. Injury Epidemiology. Sands WA, Caine DJ, Borms J. Scientific Aspects of Women's Gymnastics. Karger. 2003] In a recent study, women's gymnastics tied with men's spring football practice as the sport with the highest incidence of ACL injury; the percentage of ACL injuries among total injuries was highest in women's gymnastics (tied with women's basketball) among sports that included women's and men's soccer and lacross, and volleyball, hockey, field hockey, etc. [Renstrom P, et al. Non-contact ACL injuries in female athletes: an International Olympic Committee current concepts statement.Br J Sports Med. 2008 Jun;42(6):394-412.]
Some protective exercises could be incorporated into gymnastics warm-up routines. There's good evidence that programs that incorporate these and other exercises do have a protective effect: For example, ACL injuries were reduced by 41% in a study of 1400 female soccer players. [Gilchrist J, Mandelbaum BR, Melancon H, Ryan GW, Silvers HJ, Griffin LY, Watanabe DS, Dick RW, Dvorak J. A randomized controlled trial to prevent noncontact anterior cruciate ligament injury in female collegiate soccer players. Am J Sports Med. 2008 Aug;36(8):1476-83.]
More extensive exercises and warm-up routines have been developed for soccer players and other female athletes. I believe that these often include shuttle (side-ways) and diagonal runs, etc.
One of the most important points that are emphasized in these injury prevention programs is to avoid landing with straight legs. Most of these non-contact ACL injuries occur when the knee is completely or almost completely extended of hyperextended (the ACL may be fully loaded only when the knee joint is within ten degrees of complete extension). Injuries frequently involve a rotation on a straight knee and/or a collapse of the knee towards midline on landing. Shimokochi Y, Shultz SJ. Mechanisms of noncontact anterior cruciate ligament injury.J Athl Train. 2008 Jul-Aug;43(4):396-408. http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=2474820&blobtype=pdf]
Although gymnastics doesn't involve the cutting motions often associated with ACL injury in other sports, there may be some aspects of the sport that heighten the risk of ACL injuries and account for the high frequency of gymnatics-related knee problems. Unfortunately, the continuing emphasis on sticking the landing on dismounts of ever-increasing difficulty may, I think, substantially contribute to knee injuries. (Bad idea.) In addition, gymnasts may land with their knees (almost) completely extended (even after twisting) to generate enough force to link some additional skills; for example, my dd's floor routine for this season includes a back layout with one and one half twist linked directly to a front layout--if, as is recommended in the ACL injury prevention programs, she bends her knees substantially to reduce the shock on landing the first salto, she'll never complete the second. Emphasis on proper landing technique and a good condtioning program to protect her knees may help to protect her.