Shin Splints: A Guide to that Nagging Leg Pain

by G. John Mullen, DPT 2011 | mullen@myhousecallmd.com

Weekend warriors from Kyoto to Santa Barbra push their bodies to the limit between work, chores, driving to pick up their kids from extracurricular activities and who knows what else. Unfortunately, these hectic schedules often lead to inadequate injury prevention.  This inadequacy manifests itself in workouts as warm-ups are shortened and equipment is used improperly to save time.  These deviations from your normal training plan can lead to a number of injuries including shin splints.  A “shin splint” has become a catchall term used for any injury in the greater shin region and, unfortunately, leads to improper self-diagnosis and management.  What are all these things that can go wrong with your shins?  The three most common injuries of the lower leg are: medial tibial stress syndrome, stress fractures and compartment syndrome.

Stat Fact: Estimates have shown that “shin splints” account for 10%-15% of running injuries and up to 60% of all leg pain syndromes (1).

Lower Leg Anatomy

The lower leg is not a complicated body part but can be a real pain to heal.  Achilles’ tendon injuries, flat feet, and knee injuries are most common. In the lower leg there are two bones, the larger medial bone (the tibia) and the smaller lateral bone (the fibula).  What you commonly refer to as your shin is the tibia.  The fibula is a bit trickier, but can be palpated (this word always sounds inappropriate) on the outside aspect of the calf.  Contrary to popular belief, the calf is composed of three muscles: the superficial gastrocnemius, the deep soleus, and the plantaris.  The gastrocnemius is the powerhouse of the calf and is the explosive muscle people use for killer dunks.  On the outside of the tibia is the anterior tibialis, which can be felt if you raise your toes up. Lateral to the anterior tibialis are the peroneal muscles.  The peroneal gang is a group of three small muscles which are often weak due to what we call “lazy walking” and the use of modern shoes.

Three Common Shin Injuries

The key with shin injuries is to learn to differentiate between the dangerous and benign conditions nagging you on the front of your leg.  Medial tibial stress syndrome (MTSS) occurs at the inside portion of the tibia and is thought to include a continuum of diagnoses. Increased pressure, acutely or chronically, within the leg can result in a range of problems from leg pain alone to muscle death and nerve injury. At the same time, runners experiencing shin pain while walking or resting are considered to have a tibial stress fracture until proven otherwise (what happened to positive thinking?). Typically, pain with stress fractures worsens with continued running.  On the other hand, in the case of MTSS, pain may diminish after the runner has warmed up.


The physical examination of a stress fracture reveals focal tenderness with palpation or percussion, whereas MTSS presents with widespread tenderness (with maximal tenderness between the middle and distal third…the third closer to your foot…of the tibia). Percussion tenderness (pain when you tap on the tibia) is more likely to be positive with tibial stress fractures. An x-ray or bone scan can be used to differentiate the two diagnoses and is commonly requested by your medical doctor. While unfortunately not the best diagnostic tool, there is a very simple test to point you in the right direction.  It’s this simple: jump on one leg…if the pain occurs during landing (ding ding ding!) you probably have a stress fracture!

Compartment syndromes are characterized by the 6 P’s: pain, paresthesia, pallor, pulselessness, poikilothermia (a cool limb), and paresis/paralysis. Pallor, pulselessness, and poikilothermia are seen with vascular compromise (meaning you’re not getting adequate blood supply to your leg due to increased pressure), whereas paresis and paralysis are seen with nerve injury (3). Chronic compartment syndrome is also associated with pain during exercise that improves with rest; transient muscle weakness and sensory symptoms are also common. Often times, compartment syndrome is described as a sensation that the shin is about to explode (pleasant, right?).  If diagnosed and treated early, it does not result in irreversible vascular compromise or nerve injury. The two most commonly involved compartments of the leg are the front and deep back compartments. Treatment recommendations are still controversial, but surgery is often eminent for severe compartment syndrome.

Stat Fact: Gender (female) and increased BMI are strongly correlated with MTSS, but only BMI remained significant when controlled for orthotic use (2).  Time to shop for orthotics, ladies.

Treatment

Common management of MTSS consists of pain control and a decrease in running.  Although runners with MTSS may be able to run as they rehabilitate, athletes with stress fractures should be strictly prohibited from running and jumping until pain and bone tenderness subside. Crutches should be used if low-impact weight-bearing activities cause pain.  Some doctors encourage rest for MTSS but anecdotal evidence seems to show that specialized strengthening and stretching can accelerate healing. Worried about staying fit in the meantime?  Non–weight-bearing cross-training such as swimming, aqua jogging, and cycling can be used to maintain cardiopulmonary fitness while you recover (2).

After 4 to 6 weeks, you can slowly restart your running routine, limiting mileage increases to less than 10% per week (1). Pneumatic or air braces and pulsed electromagnetic stimulation can reduce disability and result in more rapid return to your regular activities. Because stress fractures have a high rate of recurrence, prevention is a key component of treatment. Training errors, poor nutrition, hormonal abnormalities, low bone mineral density, biomechanical deficits, and strength deficits are all possible causes.  If you’ve got yourself a good case of shin splints, be sure to make an appointment with your doctor to find out what’s causing them.

Other possible causes for people suffering from MTSS can be the female athlete triad, running shoes, and insoles. MTSS is commonly seen in female distance runners.  These runners are at risk for the female athlete triad (amenorrhea, osteoporosis, and disordered eating).  Proper running shoes, off-the-shelf shoe inserts, and custom-made inserts can all reduce injury. Your running shoe should be specific to your foot type and personal running style. If you have a rigid, cavus foot you should wear a shock-absorbing type athletic shoe.  If you have a hyperpronating foot, a motion control shoe is ideal. If you have a normal striking foot, find a stability-type running shoe (2).  Not sure what kind of foot you have?  Find your local running store and ask one of their experts to take a gander.  Shoe inserts can help but may also mask the underlying cause of the injury.

Prevention

Often times, MTSS is the result of compensating for muscle weakness.  This weaknessis is caused by muscle tightness or compensation by larger dominant muscles (such as the quadratus lumborum, piriformis, psoas, ilacus, tensor fascia lata and iliotibial band).  Both of these factors can inhibit other muscles from working properly (most notably the gluteal muscles). Simple stretching, foam rolling or tennis ball rolling slowly over these tight muscles can decrease their stiffness and instantaneously improve your strength.   Muscle inhibition caused by lack of flexibility leads to an alteration of your running style and biomechanical flaws which contribute to MTSS.

Muscle compensation can cause your bones to adapt to the abnormal movement leading to injuries such as pelvis rotation.  Pelvis rotation is a common cause of sacroiliac dysfunction which is very common in runners.   Luckily, most of these compensations are reversible with proper rehabilitation and preventive measures.  For this reason, stretching and strengthening of various muscles (rectus abdominus and gluteals) are essential to staying healthy.

To improve your safety before your next run, do some slow foam rolling over the dominant muscles mentioned above. After running, stretch those muscles again lightly .  Remember, stretching too far causes muscle activation and can increase muscle tone.  Therefore, light stretching following a run is the goal.

Your Take Home Message

When life gets busy, don’t forget to take care of yourself to prevent injuries. Stretch before every workout and finish off each session with another round of light stretching.  Lastly, be sure to work the little guys in addition to your larger muscle groups when weight training.

Questions? E-mail the Author: mullen@myhousecallmd.com

References:

  1. Korkola, M, Amedola, A. Exercise-induced leg pain. Sifting through a broad differential. Phys Sports Med June 2001;29
  2. Sports and Performing Arts Medicine. 3. Lower-Limb Injuries in Endurance Sports
  3. Larry H. Chou, MD, Venu Akuthota, MD, David F. Drake, MD, Santiago D. Toledo, MD, Scott F. Nadler, DO

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