It’s reported that shin splints affect between 5-35% of runners, most commonly during a sudden increase in mileage. New runners are also particularly prone to shin pain from the sudden, cumulative load involved in distance running. One issue with shin splints is the pathology behind the condition is unclear. A case study by Winters et al. (2017) attempting to determine the structures involved in shin splints found swelling of the periosteum, the outer layer of bone, and abnormalities in the tibialis posterior tendon were present equally in both runners with and without shin pain, showing a lack of clear structural changes behind the condition.
Impaired Hip Strength
One of the primary sources of stability in the lower leg is the activation of the muscles of the hip and trunk. While this strength has demonstrated a clear link to knee pain, the link with shin pain is less clear. Verreist et al. (2014) performed an analysis on female athletes that found a decrease in abductor hip strength was a significant predictor for shin splints. These findings conflict with those of Luedke (2015) who after examining 600 novice athletes found no link between hip and thigh muscle strength and shin pain.
Impaired Ankle Strength
The insertion point of the flexor digitorum longus muscle on the back of the tibia is the most common location for shin splints. This muscle is responsible for curling the toes and pointing the foot downward. Because this muscle is often a source of pain, it may be expected that the flexion strength of the toes could be affected in those suffering from the condition. Research by Saeki et al. (2017) showed that the strength of the big toe was significantly higher in runners with a history of shin splints compared to those without it, and no significant difference in the strength of the other toes. The authors suggested that runners with a history of shin splints may adopt a strategy of loading the big toe as a means of reducing the load on the shin.
Saeki et al. (2017) assessed the relationship between shin splints and muscle stiffness in the lower leg muscles. They found that the muscle stiffness of the flexor digitorum longus and tibialis posterior were significantly higher in subjects with a history of shin splints. However, there was no significant difference in the tightness of the gastrocnemius, soleus, peroneus and flexor halluces longus muscles.
Body Weight & Running Surface
When the foot strikes the ground during running, the joints are exposed to three to four times our body weight. A decrease in body mass decreases the likelihood of shin pain by lowering these impact forces. Likewise, running on a softer surface can also dampen the load through the shin at foot strike.
Foot Posture & Orthotics
Pronation, or a flattening of the feet, is believed to alter the load distribution through the lower limb and create strain in the muscles at their insertion point on then shin. Orthotics are commonly used as a means of decreasing foot pronation during gait, which should in theory reduce strain on these muscles, however the evidence for orthotics in shin splints is inconclusive. A systematic review by Collins et al. (2007) concluded that “there is some evidence to support the use of foot orthoses in preventing lower limb injuries but little evidence to support their use in treating overuse conditions.” In fact, Newman et al. (2013) reported that prior orthotic use is a highly significant risk factor for the development of shin splints.
There has been a considerable focus on running technique modifications in recent years as a means of decreasing injury risk. Much of the focus has been on decreasing step length and increasing step rate as a means of reducing impact forces through the lower limb. For example, research by Luedke et al. (2016) found that a lower running step rate was associated with a greater likelihood of shin injury.
Prevention & Treatment
As with most injuries, a previous history of shin splints is one of the primary risk factors for future development of the condition (Saeki et al. 2017). Training volume is a key consideration when trying to avoid shin pain.
Still having pain? Schedule an appointment with a physical therapist. At Blue Hills Sports and Spine Rehabilitation we have skilled physical therapists who can help find out why your shins hurt in the first place. We can determine if you have an imbalance in your muscles, and we can help you recover and prevent it from happening again.