Running & Shin Splints

• What are they?

The tibialis posterior and tibialis anterior are two muscles of the lower leg which attach along the length of the tibia. When these muscles are overused or there is increased stress put on them, this can irritate the fascia around the tibia called the periosteum. This is the most common form of a « shin splint ».

When the stress on the periosteum is too great or there is increased mechanical stress on the tibia (e.g. quick increase in running volume), a stress fracture can develop.

• What are the causes?

• Poor dynamic arch control: if the intrinsic muscles of the foot aren’t functioning properly in maintaining the arch of the foot while landing, there will be increased pronation (« collapsing » of the arch), which will require the tibialis posterior (whose job is to help support/lift that arch during push-off) to work harder.
  • Weak arch muscles -> collapsing of the arch -> increased demand on tibialis posterior
• Weak hip flexors: if the hip flexors aren’t functioning properly and they aren’t able to flex (bend) the hip high enough during the swing phase, the tibialis anterior (whose job it is to lift the foot) will compensate to allow the foot to clear the ground. Essentially, the tibialis anterior should be doing very little work in the swing phase as the hip flexors should lead the movement while the rest of the leg follows.
  • Weak hip flexors -> inefficient hip swing -> increased tibialis anterior requirements to prevent tripping over your own feet!
• Heel striking: when heel striking, the tibialis anterior must act to lift the foot in order to allow the heel to make contact with the ground. Therefore, a heel striking technique will require a lot more tibialis anterior work.
  • Heel striking -> increased demand on tibialis anterior to lift foot
• As previously discussed in my blog post about foot striking, heel striking puts a lot more stress on areas of the body such as the tibia (shin bone) since the muscles required to absorb the shock of landing are in a lengthened position and therefore less ready to work. Therefore, this can also lead to tibial stress fractures.
  • Heel striking -> increased stress on tibia

• How can you prevent them?

• • Arch (foot intrinsics) strengthening: by strengthening the intrinsic muscles of the foot, you can increase the dynamic stability of your arches when landing.
  • Strengthening hip flexors: in order to have a strong hip flexor mechanism, you need a strong core, so exercises involving core work and hip flexion can help produce a strong swing phase, leaving the rest of the leg to follow relatively passively.
  • Forefoot/midfoot striking: by landing on the forefoot or midfoot, the important stabilizing muscles of landing in the lower leg are activated, therefore reducing the stress put on the tibia.
    • Different techniques can be used to encourage this forefoot/midfoot strike such as wearing minimalist shoes and increasing your running cadence. See previous blog posts for more details
  • Gradual running program: by gradually increasing the stress on the muscles with a gradual running program (gradually increasing volume/speed/hill work), the tissues have time to adapt to this stress and change to meet the demands of the activity.

• How can you treat them?

• • Modifying your running program: volume/speed/hills/frequency
  • Taping: kinesiotape techniques to decrease the stress on the periosteum, athletic tape techniques to help support the arch of the foot
  • Soft tissue release: different massage techniques to decrease the tension in the muscles and on the periosteum
  • Exercise program: strengthening exercises for the intrinsic muscles of the foot, tibialis posterior, hip flexors, etc.