The term “shin splints” refers to pain and tenderness along or just behind the inner edge of the tibia, the large bone in the lower leg. Shin splintsu2014or medial tibial stress syndrome as it is called by orthopaedistsu2014usually develops after physical activity, such as vigorous exercise or sports. Repetitive activity leads to inflammation of the muscles, tendons, and periosteum (thin layer of tissue covering a bone) of the tibia, causing pain. The bone tissue itself is also involved.
The term shin splints is a name often given to any pain at the front of the lower leg. However, true shin splints symptoms occur at the front inside of the shin bone and can arise from a number of causes.
Shin splints cause pain in the front of the outer leg below the knee. The pain of shin splints is characteristically located on the outer edge of the mid region of the leg next to the shin bone (tibia). An area of discomfort measuring 4-6 inches (10-15 cm) in length is frequently present. Pain is often noted at the early portion of the workout, then lessens only to reappear near the end of the training session. Other symptoms include pain that often returns after activity and may be at its worse the next morning, sometimes some swelling, lumps and bumps may be felt when feeling the inside of the shin bone, pain is present when the toes or foot are bent downwards and/or a redness over the inside of the shin (not always present). Shin splint discomfort is often described as dull at first. However, with continuing trauma, the pain can become so extreme as to cause the athlete to stop workouts altogether.
One cause is an overused muscle, either as an acute injury or delayed onset muscle soreness (DOMS). The muscle pain is caused by any activity that involves running, jumping, also sometimes even walking. Untreated shin splints can lead to a stress reaction mid-shaft in the tibia, which can eventually lead to a stress fracture. A stress fracture can be diagnosed by a bone scan or an MRI and takes much longer to heal than shin splints.
A problem that can mimic anterior shin splints is chronic compartment syndrome (CCS). This is a serious problem that can lead to significant loss of function in the lower leg. CCS occurs when swelling within the indistensible anterior compartment of the leg reduces blood flow. This relative lack of blood, ischemia, can cause more swelling and generate a positive feedback loop. In severe cases the result can be acute compartment syndrome (ACS) which requires emergency surgery to prevent ischemic muscle necrosis due to lack of blood.CCS may be the problem if pain worsens steadily during exercise rather than improving as the ligaments and muscles warm.
If a bone problem is suspected to be causing inflammation of connective tissue, a bone scan can be useful in confirming the diagnosis. Also, in some minor cases, the best thing for shin splints is just plain rest in the legs. It may take weeks or months of healing depending on different cases of shin splints.
A primary culprit causing shin splints is a sudden increase in distance or intensity of a workout schedule. This increase in muscle work can be associated with inflammation of the lower leg muscles, those muscles used in lifting the foot (the motion during which the foot pivots toward the tibia). Such a situation can be aggravated by a tendency to pronate the foot (roll it excessively inward onto the arch).Similarly, a tight Achilles tendon or weak ankle muscles are also often implicated in the development of shin splints.
It is theorized that shin splints is caused by some runners that overstride, and land heavily on the heel with each footstrike (thus, shin splints are a common ailment in military boot camp, where trainees march extensively by extending the leg forward and forcefully striking the boot heel on the ground). When this happens, the forefoot rapidly slaps down to the ground. It is also believed by NATA athletic trainers that a contributing cause of shin muscle pain in some cases is the relative weakness of the muscles on the anterior of the lower leg compared to those in the calf. Exercises designed to strengthen the muscles of the shin are prescribed to even out the muscle imbalance. Over time, usually at least 10 days, the pain in the shins is slowly alleviated as the muscle imbalance is corrected. The shin pain is attributed to a forced extension of the muscle, in this case by the opposing calf muscles which “overpower” the shin muscles.
The immediate treatment for shin splints is rest. Running and other strenuous lower limb activities, like basketball and other sports which include flexing the muscle, should be avoided until the pain subsides and is no longer elicited by activity. In conjunction with rest, anti-inflammatory treatments such as icing and drugs, such as non-steroidal anti-inflammatory drugs (in particular, NSAID gel) may be suggested by a doctor or athletic trainer. Over-the-counter pain relievers can also be taken, though there is some controversy over their effectiveness. Stretch the muscles of the lower leg, in particular the tibialis posterior which is associated with shin splints.
Wear shock absorbing insoles in shoes. This helps reduce the shock on the lower leg. Maintain fitness with other non weight bearing exercises such as swimming, cycling or running in water.
Apply heat and use a heat retainer or shin and calf support after the initial acute stage and particularly before training. This can provide support and compression to the lower leg helping to reduce the strain on the muscles. It will also retain the natural heat which causes blood vessels to dilate and increases the flow of blood to the tissues to aid healing. Finally, the lower legs may be taped to stabilize and take some load off the periosteum.
Sometimes a “run through it” approach is used to resolve shin splints, however this approach often leads to the worsening of the injury and of the symptoms. Sometimes, a multifaceted approach of “relative rest” is successfully utilized to restore the athlete to a pain-free level of competition.
This multifaceted approach includes:
- Workouts such as stationary bicycling or pool running: These will allow maintenance of cardiovascular fitness.
- Icing to reduce inflammation.
- Anti-inflammatory medications, such as ibuprofen (Advil/Motrin); naproxen (Aleve/Naprosyn), as a central part of rehabilitation.
- A 4-inch wide Ace bandage wrapped around the region to reduce discomfort.
- Calf and anterior front of leg stretching and strengthening to address the biomechanical problems and to reduce pain.
- Stretching and strengthening exercises done twice a day.
- Run only when symptoms have generally resolved (often about two weeks) and with several restrictions:
- A level and soft terrain is best.
- Distance is limited to 50% of that tolerated preinjury.
- Intensity (pace) is similar but cut by one half.
- Over a three to six week period, a gradual increase in distance is allowed.
- Only then can a gradual increase in pace be attempted.
However, it is important to note that the amount of injury that occurs prior to any rehabilitation program plays a significant role in determining the time frame necessary for complete recovery.
As part of recovering and preventing shin splints, using good shoes (ideally compensating for individual foot differences) is important. The shin can be trained for greater static and dynamic flexibility through adaptation, which will diminish the contracting reflex, and allow the muscles to handle the rapid stretch. The key to this is to stretch the shins regularly. However, static stretching might not be enough. To adapt a muscle to rapid, eccentric contraction, it has to acquire greater dynamic flexibility as well. One way to work on the dynamic flexibility of the anterior shin is to subject it to exaggerated stress, in a controlled way, such as walking on the heels. If the muscle is regularly subject to an even greater dynamic, eccentric contraction than during the intended exercise, it will become more capable of handling the ordinary amount of stress. Experienced long-distance runners practice controlled downhill running as a part of training, which places greater eccentric loads on the quadriceps as well as on the shins. A physical therapist, athletic trainer, or doctor should be consulted before engaging in this type of training.
The long-term remedy for muscle-related pain in the shin is a change in the running style to eliminate the overstriding and heavy heel strike. Sprinting is performed on the toes, as is some middle-distance running. In most middle to long-distance running, striking with the heel, rolling through the foot and pushing off the ball is the most efficient. Competitive runners vary in styles, but as distance increases, more runners tend towards striking with the heel or mid-foot as the natural gait of the body – most marathoners can be seen to strike with the heel. Striking solely with the forefoot over distance focuses stress on the calves and underuses the hamstrings. Moreover in preventing shin-splints, heel-striking offers the best shock absorption and natural form, reducing impact stress on the calf and shin muscles.
In both postures, the center of gravity is directly over the foot. Physics requires this, because it is the condition that prevents a body from falling over. An object falls over when its centre of gravity shifts too far one way or the other outside of the range of its supporting base. Arching the back shifts the body’s centre of gravity towards the rear, so that the legs must tilt forwards to compensate; shifting the weight towards the ball of the foot, and to the toes. Bending forwards at the waist has the opposite effect: the legs tilt backwards at the ankle, shifting the weight towards the heels.
During running, the center of gravity changes dynamically. Because for most of the running cycle a drive leg extends backwards, the torso appears to tilt forwards to compensate for this. This forward tilt is similar to what happens in a standing position when one leg is raised from the ground and extended backwards. Inexperienced runners observe this forward tilt in professional athletes and attempt to imitate it by bending at the waist, which isn’t the same thing. In the forwards tilt, the torso and extended leg still form a straight line; or even a slight backwards curve. Further irritation can lead to muscle separating, or detaching, from the bone.
The shin muscles can also be somewhat alleviated by footwear and choice of surface. Runners who strike heavily with the heel should look for shoes which provide ample rear foot cushioning. Such shoes may be referred to as “stability” or “motion control” shoes. The so-called “neutral” shoes for bio-mechanically efficient runners may not have adequate support in the heel, because the runners for whom these shoes are intended do not require it. When their cushioning capability degrades, the shoes should be replaced. The commonly recommended replacement interval for shoes is 300-400 miles (480-640 kilometres). Excessive pronation can be reduced by extra supports under the arch. Running shoes which have a significant supporting bump under the arch are called “motion control” shoes, because they work by limiting the pronating motion. Also shoes with cushion shock features and shoe inserts can help prevent future problems.
Runners who race over rough terrain such as cross-country runners tend to tape just above the ankle and just below the knee with sports tape to prevent movement of bones, primarily the shin to prevent painful shin splints. This is also done to reinforce weak ankles and reduce the chance of sprains and other injuries.