Ok all very good advice! I will start this by saying before joining the Navy and entering flight school, I recieved my BS and MS in Kinesiology(Emphasis on Athletic Training) and I am a certified Athletic Trainer(ATC). I worked in college athletics for six years and a Physical Therapy office for aprox one year before OCS.
Ok on to the injury, there are many reasons an injury like this happens, some are weakness in the actual muscle fiber, some are cold muscles, some are flexibility issues and some are just freak accidents! There are three types of muscular injuries, a pull(slight disruption of muscle fiber), a tear(major disruption of muscle fibers), and of course a rupture(total tear of the muscles) with the latter almost never happening in the "belly" of the muscle, but at the tendon(where it attaches to bone).
I will only elaborate on the initial treatment of a pull since this is what the thread talks about. It was stated earlier but RICE is the absolute industry standard Rest, Ice, Compression, Elevation!
Now things to keep in mind, rest means just that, you need to take it easy for at least 3-5 days, no dynamic excercises, just light walking and everyday living. During these days, your emphasis needs to be on the other three actions.
Ice, I am just telling you what I was taught and practiced for 7 years and there are many different thoughts. Ice CAN be applied directly to the skin as long as your skin does not show adverse reaction (redness is normal welting it not). I have never had a problem with ice myself but to each their own. When icing, the rule is 15 min on 30-35 min off and this can be repeated as many times as you like. 15 min is the time that some scientist decided(after many muscle biopsies...OUCH) was the ideal amount of time it took the cold to reach its deepest point, and properly vasoconstrict the capilaries in the muscle. Basically, you dont get any more help from keeping the ice on there longer, you just start to damage the skin! 30-35 min is an appropriate amount of time for the muscle to completely warm back to body temperature(the skin may still be cool, but the muscle inside is warmed back up) One of the best things you can possibly do its stretch while icing. A slow deep stretch for about a minute....then take a minute off, then repeat.
Ok as far as compression, if you can, keep an ace bandage on it while you go about your everyday life, not so tight that your foot goes to sleep but enough to keep it warm once you start walking around. And yes compression shorts are great for once you have started working it again(I will touch on this a little later)
Elevation is misunderstood by alot of people, you cannot elevate your hamstring injury by propping it up while you watch tv. Elevation must be above the heart. The injured area needs to be above your heart.
Finally, as someone stated earlier some massage will help alot, some light friction massage(against the grain of the muscle) and some deeper lengthening massage(with the grain of the muscle) will help immensly, it may be a little painful, and ice needs to be applied immediately following any type of massage. If you have no one to help with either of these, check out this website, I have yet to run into a muscle I could not massage with this.
http://www.thestick.com
After a week of RICE, you can start in with some very light, very low intensity excercise, and if at any time you feel any "twinge", "tingle", anything strange you need to stop immediately and get some ice, this just means it was too much too fast.
If anyone is interested in a list of excercises/stretches and progression from light low intensity to hard, high intensity return to play type stuff just PM me I have already written a book here!!
P.S. The balms that people put on are strictly analgesics, meaning they only affect the skin, they do not go deep into the muscle, some poeple just like the way they feel and will absolutely swear to them. Im just telling you the science behind them...skin heat only!
And the last thing, the little girl, as we all probably remember, you were indestructible as kids, I find myself saying everyday that wow I USE to be able to do that and get up the next day! Anyway, their muscles and bones are still growing, injuries to their bodies are much less of a problem because of how fast they are growing and changing, childrens muscles and bones although looking relatively the same as ours are much more resilient.