Shin Splints and Achilles Overuse Injuries

(Understanding the cause for effective treatment)

By: John Fiore, PT
Sapphire Physical Therapy

Access to abundant outdoor activities is one of the main reasons many of us choose to live in
Western Montana. Missoula is a year-round recreational paradise which inevitably may lead to
overuse injuries. Two common and often misunderstood lower leg overuse injuries are Achilles
pain and shin splints. Understanding the cause of injury expedites treatment results and eventual
return to full activity. An anatomical explanation and treatment recommendations for Achilles
pain and shin splints follows.

Achilles Pain:

There are 4.1 million runners in the United States which is a 30% increase since 2000. Nearly
80% of runners sustain at least one overuse running injury per year, and 70% to 80% of these
injuries occur in the lower leg region. Among these common injuries are shin splints and
Achilles pain. The Achilles tendon is one of the largest tendons in the body. It is formed by the gastrocnemius and soleus muscles and serves to attach these lower leg (calf)muscles to the heel (calcaneus) bone. Unique to the gastroc-soleus-Achilles complex is the fact that this muscular-tendon group crosses three joints (knee, talocrural ankle joint, subtalar ankle joint). The Achilles tendon, therefore, is responsible for powering push-off during gait and jumping, and absorbs torsional stress placed upon the associated lower extremity joints. A rapid increase in activities such as hiking, running, or jumping increases Achilles tension. Poor calf muscle length
and weakness, poor proximal hip and core functional strength increase Achilles tension as well.

Soreness in the Achilles must not be ignored due to its limited blood supply which results in
persistent inflammation and slow tissue healing. Acute Achilles tendonitis symptoms include
pain during the push-off phase of walking or running, tenderness to palpation a few inches above the calcaneus (heel) bone, and pain climbing stairs or hills. Acute symptoms may also include a squeaky sensation in the Achilles tendon as you move your foot up and down into dorsiflexion and plantarflexion. This squeaky sensation represents inflammation in the Achilles tendon sheath and warrants immediate rest, ice, and medical
treatment to reduce inflammation. Chronic Achilles inflammation and soreness results in the
formation of a thickened knot-like structure within the Achilles and is referred to as Achilles tendinosis or Achilles tendinopathy. The thickened tendon represents scar tissue formation which will not resolve with rest alone.

Treatment of Achilles Tendonitis

In its early stages should include complete rest from running, jumping, and competition.
It is vital to reduce inflammation by modifying activity level. Anti-inflammatory medication may be prescribed by your physician, and ice/elevation will aid in pain reduction. Because the blood supply in the Achilles is limited, healing may take some time. A physical therapist will help determine the underlying cause of your Achilles symptoms as eccentric calf weakness, proximal hip/gluteal weakness, or a muscle
imbalance resulting in poor running mechanics. If acute Achilles tendonitis is not treated in a timely manner or if
symptoms are ignored, then Achilles tendinosis may develop. The associated tendinosis lump of scar tissue decreases the elasticity of the Achilles and may lead to bone irritation at the
Achilles attachment (calcaneus). Addressing the scar tissue with properly applied physical therapy cross friction massage, instrument assisted soft tissue mobilization (IASTM), and anti-inflammatory modalities such as Iontophoresis are beneficial. If symptoms do not resolve in a timely manner, orthopedic options
such as platelet rich plasma (PRP) injections should be considered. Once pain is gone, running
mileage and sports participation should be resumed very gradually. Strengthening the Achilles
tendon and calf musculature in an eccentric (lengthened) manner will reduce injury recurrence.
Do not ignore Achilles pain. See treatment immediately to expedite your return to running.
Because of the unique dynamic musculoskeletal forces and complex synthesis of movement
involved in running and jumping sports, treatment of running injuries must not focus solely on
static, passive interventions. Physical therapy as directed by your physician is a vital component
in returning to full running ability following an Achilles tendon injury.

Medial Tibial Stress Syndrome (AKA Shin Splints):

Another overuse injury is medial tibial stress syndrome. Previously referred to as shin splints,
medial tibial stress symptoms include pain and tenderness along the border of the tibia (shin)
bone which increases with weight bearing activities such as running and jumping. Poor
treatment outcomes are often associated with poor compliance with recommended activity
modification, as well as treatment of the site of pain alone. While poor core, hip, and intrinsic
muscle strength often plays a role in the cause and treatment, addressing tibialis posterior muscle
function is necessary for long-term symptom resolution. The tibialis posterior muscle plays a key role in the mechanics of weight bearing locomotion. The tibialis posterior allows athletes to
efficiently run, cut, and jump. The tibialis posterior, therefore, must be included in the treatment of medial tibial stress syndrome. Located on the posterior aspect of the lower leg, the tibialis posterior is deep to the calf musculature (gastroc-soleus muscle complex). The tibialis posterior originates on the posterior side of the upper fibula and tibia, and inserts on the navicular, cuneiforms, cuboid, and 2nd , 3rd,and 4th metatarsal bones on the bottom of the foot. An important function of the tibialis posterior muscle is its role as a major medial
arch stabilizer during walking and running. The tibialis posterior serves to stabilize the 26 bones which form the foot. Weakness of the tibialis posterior results in excessive pronation, poor foot/arch stability, lower leg torsion, and increased tension in the gastroc-soleus muscle group leading to medial tibial stress syndrome. Prolonged,
untreated inflammation in this area may lead to a bone inflammatory response. If not treated properly, tibial stress fracture may result from bone inflammation and tibialis posterior weakness.

Treatment of Medial Tibial Stress Syndrome

Treatment begins with proper diagnosis. A comprehensive evaluation and gait assessment will reveal dysfunctional gait mechanics. Muscle strength testing in both weight bearing and non-weight bearing may
reveal underlying weakness in key supporting muscles of the lower extremity and core. Inflammation reduction is the initial goal, followed by addressing the mechanics of weight bearing activities. A physical therapist will provide you with localized and functional strengthening exercises to improve the support of the foot and lower extremity. Learning to fire the tibialis posterior muscle in weight bearing is challenging when the
body has been habitually compensating. Releasing tension and muscle tightness in the gastroc-soleus muscle group through manual therapy techniques will decrease localized sensitivity in the tibia bone. An evaluation of footwear and a gradual return to activity is the final step towards a successful return to pain-free activity and sports.

References:

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