Shin splints, cramps, thrombosis, oh my!

Lower leg pain often plagues runners. The trick is distinguishing pain from an acute injury, overuse, or an emergent problem. In today’s feature article, Pat Gilliam offers an overview of lower leg injuries and identifies the particular characteristics of each syndrome.

In most acute injuries, the athlete experiences a sudden onset of pain and disability, often accompanied with a tearing or popping sensation. Muscle and tendon tears are graded as to severity of injury either through clinical exam or magnetic resonance imaging (MRI) (see table 1). Up to 65% of all calf strains occur in the medial head of the gastrocnemius and over half of these extend into the soleus as well (see figure 1)(1). Strains to the gastrocnemius occur primarily during sprinting, jumping, hill training or changes in direction due to the preponderance of fast twitch fibers within the muscle. Soleus strains tend to happen during endurance events or overextended training schedules because the muscle consists mostly of slow twitch fibers.

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Table 1: Grading system for calf injury

Grade	Symptom	Site
1	Pain during or after activity ROM normal at 24hr Normal power and initiation Pain on contraction	Myofascial - injury in the peripheral aspect of the muscle
2	Pain during activity and restricts participation Limitation with ROM Pain on contraction Reduced power on testing	Musculotendinous - Injury within the muscle belly most commonly at musculotendonous junction (MTJ)
3	Extensive tear Sudden onset of pain Significantly reduced ROM Pain on walking Obvious weakness on testing	Intratendinous - An injury which extends into the tendon
4	Sudden onset of pain Significant limitation to activity Palpable gap in muscle May be less painful than Grade 3	Complete tear of muscle or tendon

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Figure 1: Anatomy of posterior leg

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Chronic injuries

Gilliam’s article overview of pathologies that strike the lower leg helps differentiate between symptoms that appear the same. For instance, sural nerve neuropathy may send a burning or aching sensation down the back of the lower leg that mimics the sensation from chronic exertional compartment syndrome. While similar symptoms, treatment for each is quite different. Other issues, such as medial tibial stress syndrome (commonly known as shin splints), may be treated by addressing altered biomechanics. Calf pain may even be caused by more unusual pathologies, such as a Baker’s cyst.  This overview provides a starting point for diagnosing the runner with leg pain. For more specific information, explore leg injuries under the anatomy tab to bring science to the treatment of leg pain.

Reference

1. Curt Sports Med Rep. 2016 Sept-Oct;15(5):320-4