(From the Mayo Clinic.)
Shin splints are a drag. Plain and simple. Irish dance is all about being on the toes and jumping/hopping almost continually, all of which is just asking for shin splints. I wonder if there is a higher incidence of shin splints in ID since the technique requires that the heels never contact the floor?
As usual, there are many things that can contribute to a dancer getting shin splints, but along with the rehabilitation and treatment options, there is really only one cure when you get them…rest. No dancer wants to hear that, but it is a fact. And then once the pain is gone, besides starting activity again slowly and carefully, there are things that need to be evaluated and addressed so that the shin splints do not return, and that requires a professional. See an orthopedic doctor to make sure all is well…spill your guts about your shoes and the floors you dance on. And then head off to a sports therapist or trainer. Shin splints do not have to be a chronic problem.
I found this great definition at HealthCareClinic.org: “Splints (Periostitis) – The term shin splints is a common misnomer in sports medicine. It does not imply a specific diagnosis, rather it is the symptom of pain over the front of the tibia bone. The pain from shin splints can be due to either problems of the muscles, the bone, or the attachment of the muscle to the bone. Therefore, ‘shin splints’ is simply the name given to pain over the front of the lower leg.”
The more common technical phrase for shin splints is “medial tibial stress syndrome.” Other problems such as posterior compartment syndrome and stress fractures can also cause shin pain.
Shin splints are very often caused by an overload on the tendons and connective tissues that attach the muscles of the lower leg to the shin bone, the tibia, causing inflammation and pain. For dancers, this overload can be caused by jumping back into vigorous exercise after there has been a lay off and dancing as if one is still in peak form. It can be caused by dancing on concrete floors. It can be caused by bad posture that contributes to leg misalignment. It can be caused by medially rotated hip joints, knock-knees, flat feet, feet with really high arches, and loose ligaments in the foot and ankle that allow hyper-pronation. It can be caused by not rotating from the hip sockets as this encourages hyper-pronation. It can be caused by tight calf muscles and an imbalance of the relative strength between the muscles of the lower leg. In this same vein, a rapidly growing dancer in peak form might develop some symptoms because of the difference in growth rates of the bones and muscles…bones grow first, muscles catch up.
In my experience as a dancer and teacher, I have found that one huge contributor to shin splints is over- or hyper-pronation of the foot. Pronation happens when you roll your foot inward, dropping your arch closer to the floor. Hyper-pronation is very common in dancers who force their turn-out from their knees and ankles. Forced turn-out results in habitual hyper-pronation which sets a dancer up for shin splints (as well as big toe joint pain, bunions, fallen arches/plantar fascia pain, knee problems, etc, etc, etc). Landing from jumps does involve some pronation as it is part of the landing mechanism of the foot, but over-pronation, loose ligaments, flat feet, or even arches that are too high all mess with the landing mechanism (the sequence of events in the foot) which puts tremendous strain on the lower leg muscles and all the connective tissues which then pull on the tibia. And once again, because we women have wider hips, the angles of the applied forces used to jump and land are more acute which exacerbates the problem…translation, women and girls are more prone to shin splints just as they are to knee and hip problems.
Obviously, the sheer pain of shin splints can and will stop a dancer in her tracks. So, taking care of them is paramount. But there are those who want to be brave, who want to dance through the pain. Please don’t. Stress fractures can result if shin splints do not heal and the underlying causes are not addressed, and then you are on to a whole new set of problems that take even longer to heal. The Mayo Clinic advises that you should “[c]onsult your doctor if rest, ice and over-the-counter pain relievers don’t ease your shin pain. Seek prompt medical care if:
*Severe pain in your shin follows a fall or accident
*Your shin is hot and inflamed
*Swelling in your shin seems to be getting worse
*Shin pain persists during rest
So, how do we prevent shin splints?
1) If you are coming back after a break, start slowly. We like to go at it gang busters as if we never stopped, and your body will oblige you because of the sheer excitement of being back in class. But you will pay by being very sore and by perhaps setting the shin splint train in motion.
2) Make sure there is an adequate calcium intake, especially for growing children and girls going through puberty. I am a firm believer in calcium supplements (unless there are kidney issues).
3) Warm up well and correctly, add more strengthening exercises for the lower leg such as slow releves (click here for more info) and this one with a partner:
Sitting on the floor with your legs straight out in front of you, pull your toes back so they are pointing up to the ceiling.
Partner, put your hands on the top of the feet and try to make the feet move to a pointed position while your sitting partner resists you. You are pulling your hands towards you while your partner’s feet are pulling against your hands, pulling towards them. 
This helps strengthen the muscles at the front of the leg. Do this 10 times, holding for a count of 10, and then relax in between. (My wimpy model, Maggie, started whining that this was hard…guess we should be doing these regularly.)
4) STRETCH!!! Go here for pics of the 3 most effective stretches. I always did these with my students before class gently, and then again at the end, though we did the stretch for the front of the leg differently than it shows in the link. The third stretch in the series that stretches the front of the lower leg is a great one. And I like the fact that it is shown being done while sitting. This puts you totally in charge of the stretch. Just make sure your foot is aligned correctly with your lower leg…see pic #3 below.
That same lower front leg stretch can be done GENTLY with your partner after the exercise I illustrated above.
First, for both of you, identify the straight point position.
#1 – This is an inverted/sickled pointed position. This is incorrect.

When you are stretching make sure the foot is not sickled as in #1 above and as it is in this pic below.

#2 – This is an everted/winged position. While this can be a desirable position (in ballet in particular), I feel it trains the foot to habituate a hyper-pronated position. To me, this is incorrect.

No matter your feeling on winging, when you are stretching make sure the foot is not everted as in #2 above and as it is in this pic below.

#3- This is a wonderfully aligned foot. Good point, nice straight line down the shin through the foot.

That is the position in which I GENTLY stretch the foot through its point. Notice in the pic below that I am using two hands. I grasp the foot and gently pull it towards me as I slowly stretch the foot out and then down. Do not simply press down as that will compress the ankle and heel. You will know you are doing it correctly when your dancer sighs and says, “Oh Mama, that feels so good…aahhh.”

They will feel a nice gentle stretch above and below where I am indicating here on Maggie’s shin.

5) If you do pronate, you should consider arch supports. you can buy them at the drugstore, but I personally would talk to a professional about getting orthotics that are built just for you. It is SO worth the time and expense to safeguard your dancing body.
Something to think about if your pronate your feet is that if your shoes are stretched out they are offering no real support for your feet, even if you do have arch supports. Loose shoes and dancing should not go together.
6) If you do dance on concrete floors, please get some thick insoles for your shoes, soft and hard alike. I personally love the gel insoles. More padding in the shoe means more safety for the dancer.
Ok. So…you have been the model of responsible dancer health, but you have been hit with shin pain. It is the first night after your first class after a long vacation. Or you have been growing. Or you have been working on a new floor. Or you are working harder on your turn-out. Or you are just plain working as hard as you can for the coming Oireachtas. Damn. Now what?
R.I.C.E.R. This is rest (R), ice(I), compression(C), elevation(E), and getting that referral (R) for the necessary medical treatment. This is ALL so important. In my book, REST (meaning, NO DANCING!) is most important whether we like it or not. ICE alleviates pain as well as inflammation. COMPRESSION (ace bandage or taping) and ELEVATION (above the hip joint) both help to alleviate inflammation as fluids are directed out of the affected area. Anti-inflammatory over-the-counter medications like Ibuprofen (Tylenol is not an anti-inflammatory medication even though it is a pain killer) help this process as it alleviates the swelling as well as the pain. And then, to stop the shin splints train, REFER this problem to an expert: an orthopedic doctor, a sports medicine doctor, a sports therapist. There must be an analysis of any misalignment and pronation, and then professional direction for correction through strengthening, stretching, taping, and adding orthotics if needed. If dancing is important to you, take shin pain seriously.
More resources: I have to say here that the best information I found came from sports or running sites. The dance sites, except for Harkness, were incomplete, derivative, and frustratingly crunchy-granola. Please feel free to send more links to me.
Wikipedia: Shin Splints – excellent, though very technical, explanation of the causes of shin splints, how misalignment of the foot causes the muscles to work in an imbalanced way which puts excess stress on the tissue connecting to the tibia.
Harkness
The Stretching Handbook
The Runner’s Web
Google it…there is so much on the web it makes my head spin.
Click for more kinesiology info: Dance Kinesiology
To start educating yourself, try here.