Although Shin splints is a common injury, it still remains a poorly understood condition. It is a general term applied to a variety of conditions characterized by pain and irritation of the tibia. Anterior Compartment Syndrome (ACS) is another injury often mistaken for shin splints. ACS is a condition in which high pressure within a closed fascial space reduces capillary blood flow below a level necessary for tissue viability and can only be relieved by decompressing the muscle compartment.
Signs & Symptoms:
1) Small muscle and tendon tears at the periosteal attachments resulting in myofascial inflammation and pain
2) Small tears within the muscle tissue resulting in edema and myotactic contraction
3) Sub periosteal avulsions
4) Tears and irritation of the tibiofibular interosseous membrane
Walking, jumping, and running on hard and uneven surfaces, improper or poor footwear and a sudden change in training habits have all been noted to cause shin splints. The frequent occurrence early in training programs suggests that the physiological condition of the muscle may be a factor. Furthermore, foot pronation is also a common cause of shin splints. When the foot is pronated, this places undue stress on the Tibialis Anterior and Posterior which are involved in the support of the medial border of the foot. In addition, some studies speculate that there is an increased risk in women. This may be due to joint laxity and a wider pelvis, causing greater varus angulation of the lower extremity.
The protective role of muscle has been emphasized since muscle action stabilizes the joint structure and protects the skeletal system by function of shock absorbers. Too much stress causes the muscle system to fatigue and resulting in loss of efficiency and absorbing shock. The force must be dissipated by being transmitted to the muscle tissue and to the periosteal attachment to the bone. The shock passing up the leg destroys bone cells and prevents remodeling of the damaged bone, hence stress fractures can occur. With the foot pronated, the medial border of the foot must absorb abnormal stress as the rear foot moves from heel strike through midstance to thrust with the forefoot.
1) Pain along affected area either during weight-bearing or to the touch. The pain onset is usually gradual but may increase to the point of being disabling if the activity is continued or increased.
2) Inflammation and warmth are present and the subject may limp or walk with a stiff-legged gait.
3) Weak affected muscles and tight opposing structures.
Shin splints may be categorized according to the compartments of the lower limb.
1) Anterior Compartment:
Pain is normally felt along the inner distal 2/3 of the tibial shaft. There is inflammation, stiffness and an ache that is present at the beginning of activity. Pain can also be present at rest as swelling may be causing increased pressure on the nerve endings.
The most commonly involved muscles in anterior shin splints are the Extensor Halllucis Longus and the Anterior Tibialis muscle. These are decelerators of the foot at heel strike. The Tibialis Anterior is responsible for ankle dorsiflexion and inversion and the Extensor Hallucis Longus is responsible for extension of the big toe and assist with foot dorsiflexion and inversion. With Anterior shin splints, the opposing triceps surae (calf muscle) are strong and tight which prevent the foot from dorsiflexing to the degrees necessary for efficient function hence causing the tibialis anterior to work overtime and the muscle attachments to pull away from the periosteum (membrane that lines the outer surface of the bones).
2) Lateral Compartment:
The Peroneus Longus and Brevis muscles are those overworked with lateral shin splints. There are responsible for plantar flexion and eversion of the foot. They become fatigued in side-to-side sports, such as tennis and aerobics. A hypermobile first ray (big toe) can also cause fatigue of the Peroneus Longus. Pain is usually experienced along the lateral malleolus (outside ankle) and the distal 1/3 of the fibula.
3) Medial and Posterior Compartment:
The Tibialis Posterior is the muscle most commonly affected of all the posterior/medial muscles. It’s the key stabilizer of the ankle and supports the medial arch of the foot. It also creates inversion and plantar flexion. In addition, it also tries to assist the re-supination of the subtalar joint (ankle). A runner can stress this muscle for running prolongs the pronation phase in the gait cycle and hence more supinatory effort by the Tibialis Posterior is needed. Weak or a ruptured Tibialis Posterior can lead to flat feet and a valgus deformity of the foot (outward angulation).
Image taken from Google: footeducation.com
Pain is usually felt 3-6 inches above the medial malleolus (inside ankle).
Image taken from Google: richwoodstrack.com
Images taken from Google: orthoticshop.com
1) Rest. Pain should not be present for a minimum of 2 days. A gradual return to activity with a decreased intensity and frequency is recommended.
2) Possible Anti-inflammatories ( Prescription or Over The Counter (OTC))
3) Physiotherapy: Modalities such as ice, Ultrasound, taping, stretching and strengthening exs.
4) Massage to decrease swelling and pain
5) Orthotics should be considered in order to help correct abnormal foot biomechanics.
6) Proper footwear
7) Running on soft sand, sides of roads, and slanted tracks should be avoided in the case of posterior shin splints. Staying away from hills, running or walking on softer surfaces is beneficial for anterior shin splints.
Michelle Price BSc. PT, CAFCI
WBFF Figure Pro