Runner or non-runner, most people have at least heard of shin splints. Its medical term is medial tibial stress syndrome. Shin splints present as pain on the inside (the medial side) of the tibia (the shin bone on the inside of your shin). You’ll generally feel an aching pain near the border of the tibia and the calf muscles. You will most likely feel soreness when you poke around in the area.
First up, you’ll feel the pain mostly just at the end of a run, but if left untreated, the injury can progress to become a sharper, more stabbing or burning sensation, which can hurt during the whole run, or worse, even when you’re just walking around.
Shin splints can be either isolated to a small area on the shin bone, or they can be more generalised, spreading over a greater length of the bone.
If you have a seriously painful shin splint, a full blown stress fracture needs to be ruled out, particularly if your pain is more localised to a small area. A stress fracture can be diagnosed via MRI, so you will need the referral of a medical practitioner.
Who is at greater risk of shin splints?
- This is one injury which is NOT more common amongst experienced runners doing lots of mileage. Shin splints are actually more common amongst people with less experience of running.
- Whilst shin splints are less common amongst the population of runners who are putting in big miles week after week, mileage and running surfaces will play a role in the development of shin splints in some individual runners.
- Women are 2-3 more times more likely to develop shin splints than men. (1)
- People performing any kind of activity which places more force on their tibia than it is ready to cope with – which is another way of saying, don’t do too much too soon!
- Anyone who greatly increases the amount of high impact activity they are used to, or greatly increases the level of intensity of that activity, over a short time period – for example someone who runs 10km a couple of times a week, and then takes up a stop start game such as tennis two times/week
- People with a smaller calf circumference, or who have poor bone density. In women, every 1 cm decrease in calf circumference increased the risk of a stress fracture by four times in one study(2)
- People with poor calf muscle strength. A study of athletes with shin splints showed healthy athletes had stronger calves than those with shin splints (33 single leg calf raises versus 23 sinlge leg calf rasies) (3)
- People who’s feet strike the ground with greater force (ie they have greater “impact loading rates”-the pace with which the force of your footstrike increases as your foot hits the ground) (4)
- Runners with weak hip adbuctors, or who’s hip abductors are not firing in the right manner during the running stride. (5,6) (Hip abductors are the muscles in the side of your hip which pull your leg away from your body, and help to stabilise you, particularly when you are running, walking, or standing on one leg).
Causes of Shin Splints
It used to be thought that a shin splint was a soft tissue injury, as distinct from a stress fracture of the tibia, or a stress reaction, which are bone injuries. The theory went, that tightness in the calf muscles, and muscles just above the ankle which insert onto the tibia, became tight, pulling at the periosteum (a structure that’s a bit like skin and wraps around the bone). However a 1994 study (7) showed that the pain felt on and around the tibia, did not correspond with the insertion points of these muscles.
More advanced imaging studies have shown that shin splints fall on the mild end of the bony injury spectrum, with stress fractures at the severe end of the spectrum. CT scans have shown that pockets of low bone density correspond with areas of pain on the tibias of runners with shin pain. (8)
All sounds a bit “stressful” doesn’t it? But the good news is that once the runners had recovered from their shin splints, the pockets of low bone density no longer appeared on the scans. (9) This means, that if you have had shin splints, the actual injury doesn’t make you more susceptible to it happening again. That’s not to say you won’t get a shin splint again! Whatever caused you to be predisposed to the injury in the first place, could mean you’ll be more likely to reinjure the area, if you don’t address the underlying cause.
What has calf strength and size got to do with shin splints, if we now know that a shin splint is a bone injury, not a soft tissue injury?
Bone, like the rest of the body, responds to the demands put on it. If you have small, weak muscles in your calf, then you won’t be able to put much force on the bones in your lower leg during exercise. Less stress, means there’s less stimulus for bone development, and you won’t have very thick bones. (10) If you suddenly start to put a lot more stress on your bones – like ramp up your mileage or intensity quickly, your bones won’t be strong enough to cope, and you are at risk of developing a bony injury in your tibia, whether that be shin splints or a more serious injury.
What’s going on with your tibia when you run?
Your tibia takes a slight backbend when your foot hits the ground. One possible reason for stronger calf muscles possibly preventing shin splints that the muscles are able to prevent the bone from too much bending and too much stress being placed on it.
Stressing the bone is actually how the bone gets stronger. The body remodels the bone to be stronger and thicker in response to the stress placed on it. Prior to bone growth, there is a period of resorption of bone material. The body is getting rid of some old bone material, in order to be able to make the bone stronger- (a bit like tearing out walls in your house to build it back up again when you’re doing renos!).
When you start to pick your training up, there’s a period of about a month, when the bone is actually weaker
When you start to pick your training up, there’s a period of about a month, when the bone is actually weaker, due to this resorption of bone material that precedes bone growth (11). If the stress on the bone out paces bone growth for an extended period of time, a bone injury will result. It may just be shin splints, or you may have a stress reaction, or develop a stress fracture. So if you have small or weak bones to begin with, you are more susceptible to injury during this remodelling period.
Given the most likely causes of medial tibial stress syndrome (shin splints), particularly in women are: lower bone density, smaller bone size, small calf muscle size and reduced calf muscle strength, it would seem sensible to work on these areas prior to, or whilst you are increasing your workload.
To improve your bone density, you could consider taking a Calcium/Vitamin D supplement in a therapeutic dose. This type of supplementation reduced the risk of tibial stress fractures by 25% in one study (11). As it would appear that shin splints are on the same “bony injury spectrum” as stress fractures, using a bone strengthening supplementation protocol could help to prevent shin splints in those with poor bone density and strength. At the very least, include high calcium foods in your diet, and get some early morning sunshine.
By increasing your workload gradually, you will be stressing your bone, providing it with the stimulus to remodel, without overdoing the stress and causing injury.
Calf Muscle Size and Strength
Prior to ramping up your mileage, it is probably worthwhile undertaking a good strengthening program for the lower leg. It’s likely strengthening these muscles will absorb some of the shock of footstrike and reduce the strain on your tibia. Your tibia will also increase in strength in response to an increase in muscle strength and size. (10)
Sometimes you can run through the pain of an injury. You know the type- you have a little niggle, you ignore it and it goes away. That’s not really an option with shin splints. You don’t always need to stop running completely, but often the best option is to reduce your workload.
Treatment for shin splints involves reducing the impact on the tibia whilst running, strengthening the bone, and strengthening the surrounding muscles.
You must see your doctor if your are experiencing any of the following signs and symptoms:
- severe pain in your shin after a fall or accident
- a shin that feels hot
- a shin that’s visibly inflamed
- swelling in your shin area that gets worse
- pain in your shins even when you’re resting
- calves that feel hot or visibly inflamed
- fluid retention in the lower leg, particularly accompanied by pain heat
To reduce the impact through your tibia whilst running, you could look at increasing your stride frequency. (10)
Whilst increasing your stride frequency is likely to reduce the impact on your tibia, it’s something that should be worked on slowly, and with caution. Any change to your stride can impact other areas of your body, so it’s something that should be worked on under the guidance of a coach.
Change your running surface?
Somewhat counter-intuitively, running on a harder surface in thinner shoes, might help reduce impact, as it reduces your leg stiffness. Your leg stiffness tends to adjust to compensate for softer ground and shoes, so there’s little change to the forces going through your legs if you’re running on a more cushioned surface. (13)
Running on softer ground however, could help build strength in the muscles of your lower leg, particularly those used for stability. Softer surfaces tend to be more uneven, so your stabilising muscles are called into action more than on a more even surface such as a road.
Both these methods for reducing the impact through your tibia on landing do bring up the possibility of injury to other areas of your body, and should only be used if you have continual shin problems. They should be introduced under the guidance of a coach, and should not be used for preventative treatment.
Orthotics are also an option to aid in the treatment of shin splints. Some runners have found them helpful, possibly because they redistribute pressure on the bottom of the foot. (14)
Increasing your strength
If you’re new to running, you’re planning to pick up your mileage, you have any of the risk factors mentioned above, or if you experience chronic shin pain, you definitely should undertake a strengthening regime for the leg.
This protocol will give you a good all over strength base for the lower leg and hip. It is a protocol for beginners, and should progress to more functional exercises.
For the first week, all you need to do is a set of two legged standing calf raises, with your body weight only, to exhaustion, twice daily. Stand on the edge of a step and lower your heels down, below the level of the step. Come up onto the ball of your foot and hold momentarily, before dropping down again.
After a week of calf raises, and if your symptoms are not getting worse for doing the calf raises, you could include the following exercise:
Single leg standing calf raises –a calf raise standing on one leg. If you need to steady yourself by holding onto something, make sure you have something on either side of you, so that you don’t lean to the side where your hand is holding on. Steps with a railing on either side are ideal.
Toe walking – walking on the ball of your foot with your heels off the floor –we normally call this walking on our toes, but not too many non-ballerinas actually walk on their toes!
Shoulder Bridge –Lying on your back, knees bent, feet flat on floor. Hands at your side. Lift your hip off the floor, squeeze your buttocks, and hold for a couple of seconds. Return to floor, repeat. Keep your pelvis steady.
When you are ready to progress, you can lift one foot off the ground, then the other-after you have put the other one back onto the ground of course – and continue alternating in a “marching” action. Make sure you can feel your glutes squeezing and your pelvis isn’t dropping down to one side.
A further progression is to take one leg off the ground, extend it out so that it is straight, and your knees are next to each other. Keeping the leg in that position, slowly, and in a controlled manner, lower the hips towards the floor. Without resting, come back up to the start position. Repeat.
Tip: have your feet in quite close to your bum, especially to start with. The further out your feet are from your bum, the more involved your hamstrings become, and you might find yourself cramping in the hamstrings before your glutes can get a good workout.
Clam – In a side-lying position, bend your knees and your hips. Keeping your ankles together, lift the knee of your top leg into the air, through the full range of movement of the hip. Return to starting position and repeat, without resting.
Be careful that you keep one hip stacked on top of the other. People have a tendency to roll backwards to get their knee higher into the air, and this can make you use the muscles at the front of the hip too much. If you are feeling this working the muscles in the front of the top of your leg, try rolling forwards slightly. You should then feel this more towards the side/back of your hip.
There are heaps of other exercises you can do to help with calf strength, pelvic stabilisation and hip abductor strength and function. These exercises above will give you a good foundation of strength and stability from which you can embark on a more functional protocol.
When should you return to running?
For some cases of shin splints, you may actually not need to stop running completely. For mild cases, you can often get away with reducing your workload to give your body time to strengthen the shin bone. If you do keep running through shin splints, make sure you listen to your body, and if the pain gets worse, you should take some time off.
Whether or not you should be completely pain free again before you start, is something you need to decide in consultation with your coach and/or medical professional.
When you do start back, you should modify your intensity somewhat to reduce the impact stress on the bone. Remember too, that you can’t start back at your pre-injury mileage. Drop you mileage back considerably – better to be safe than sorry- then build gradually for 2-3 weeks. After 3 weeks, you should drop your mileage down for a week, to allow the body the bone to adapt to the straining and strengthen.
Remember, a shin splint is a mild bony injury, which if disregarded, can become a real problem.
- Yates, B., The Incidence and Risk Factors in the Development of Medial Tibial Stress Syndrome Among Naval Recruits. American Journal of Sports Medicine 2004, 32 (3), 772-780
- Bennell, K. L.; Malcolm, S. S.; Thomas, S. A.; Reid, S. J.; Brukner, P.; Ebeling, P. R.; Wark, J. D., Risk factors for stress fracture in track and field athletes: a twelve-month prospective study.American Journal of Sports Medicine24 1996, 6 (810-818).
- Madeley, L. T.; Munteanu, S. E.; Bonanno, D. R., Endurance of the ankle joint plantar flexor muscles in athletes with medial tibial stress syndrome: A case-control study.Journal of Science and Medicine in Sport 2007, 10 (6), 356-362.
- Milner, C. E.; Ferber, R.; Pollard, C. D.; Hamill, J.; Davis, I. S., Biomechanical Factors Associated with Tibial Stress Fracture in Female Runners. Medicine & Science in Sports & Exercise 2006, 38 (2), 323-328.
- Verrelst, R.; Willems, T. M.; De Clercq, D.; Roosen, P.; Goossens, L.; Witvrouw, E., The role of hip abductor and external rotator muscle strength in the development of exertional medial tibial pain: a prospective study British Journal of Sports Medicine 2013.
- Verrelst, R.; De Clercq, D.; Vanrenterghem, J.; Willems, T. M., The role of proximal dynamic joint stability in the development of exertional medial tibial pain- a prospective study. British Journal of Sports Medicine 2013, 0, 1-7.
- Beck, B. R.; Osternig, L. R., Medial tibial stress syndrome. The location of muscles in the leg in relation to symptoms. Journal of Bone and Joint Surgery 1994, 76 (1057-1061).
- Magnusson, H. I.; Ahlborg, H. G.; Karlsson, C.; Nyquist, F.; Karlsson, M. K., Low regional tibial bone density in athletes with medial tibial stress syndrome normalizes after recovery from symptoms. The American Journal of Sports Medicine 2003, 31 (4), 596-600.
- Popp, K. L.; Hughes, J. M.; Smock, A. J.; Novotny, S. A.; Stovitz, S. D.; Koehler, S. M.; Petit, M. A., Bone Geometry, Strength, and Muscle Size in Runners with a History of Stress Fracture. Medicine & Science in Sports & Exercise 2009, 41 (12), 2145-2150.
- Beck, B. R., Tibial Stress Injuires-An Aetiological Review for the Purposes of Guiding Management.Sports Medicine 1998, 26 (4), 265-279.
- . Heiderscheit, B. C.; Chumanov, E. S.; Michalski, M. P.; Wille, C. M.; Ryan, M. B., Effects of Step Rate Manipulation on Joint Mechanics during Running. Medicine & Science in Sports & Exercise 2011, 43 (2), 296-302.
- Butler, R. J.; Crowell, H. P.; Davis, I. M., Lower extremity stiffness: implications for performance and injury. Clinical Biomechanics 2003, 18 (6), 511-517.
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