What Is A Stress Fracture?
Suffering a stress fracture would have to be one of the most frustrating injuries a runner can experience since the entry level cull on running when diagnosed with a stress fractures starts at about 6 weeks and some of this may also need to be spent in a boot to immobilise the area.
Stress fractures were initially called “march fractures” first noted in Prussian soldiers who marched excessively. As the name “stress fracture” suggests, this is a small crack in the bone (one that doesn’t extend completely through the bone). These fractures can occur in many bones of the body and runners are particularly susceptible. When you run and increase your training load your muscles and heart and lungs… aren’t the only things that need to adapt and get stronger. So do your bones. If the repeated pounding associated with running overloads the bodies ability to adapt to the applied stress placed on the bones, then stress reactions of the bone can occur and progress to stress fractures.
What Are The Common Running Stress Fractures?
Runners can experience a variety of stress fractures. The most common stress fractures from running are in the:
- Tibia – The tibia is the large long bone of the shin, on the inside of the lower leg.
- Metatarsals – These are the long bones in the forefoot there are 5 of them and the most common sites for stress fractures are of the second and third metatarsals. Metatarsal are named where by the big toe is labeled the first metatarsal and the little toe is the fifth.
- Femur – The femur is the large thigh bone, stress fractures of this bone may occur in the shaft of the bone or at the neck of femur, at the level of the hip.
- Fibula – Stress fractures here as less common, the fibula is the long thinner outside shin bone. The major weight bearing bone of the lower leg is the tibia and is subsequently the most common bone for runners to suffer a fracture in.
- Navicular – This bone is one of the small bones of the mid foot and is positioned on the inside of the mid foot around the middle of the arch of the foot.
- Calcaneus – The calcaneus is the heel bone and although not particularly common runners can still experience fractures in the heel.
- Pars Intraarticularis – These are lower back stress fractures, also can be referred to as a spondylolysis or spondylolisthesis.
Causes Of Stress Fractures
Stress fractures running could be considered to have two main causes. Firstly one of these causes being simply too much force on a bone and secondly weakness of the bone structure to which the force is applied. Both of these causes may have sub-factors as to why the bone stress is too great and why weakness exists in the bone to start with. Basically these causes can result from a number of different factors and if the repeated strain and force to the bone is greater than the strength of the bone, then you will develop a stress fracture.
Forces applied when running can be impact loading forces or active forces. Impact loading forces are referring to the degree of shock that travels up your foot and leg when the runner initially contacts the ground. Active forces and the forces which are generated when the runner is pushing their body off the ground.
Bone Densities Role In Stress Fractures
When considering potential causes of stress fractures, bone density and bone shape may play a roll. A family history of osteopenia or osteoporosis meaning an individual has a lower than average or significantly lower than average bone density may be a risk factor for stress fractures running specifically in women.
In females bone density and menstrual irregularities play a role in having a greater risk of suffering stress fractures. It is possible that stress fractures running may be indicative of underlying health issues, if a female is amenhorreic (meaning they are missing their monthly period), this can impact immediate injury risk and as well as that impact the bone density for the rest of their life.
Disclaimer: Sydney Physio Clinic provides this information as an educational service and is not intended to serve as medical advice. Anyone seeking specific advice or assistance on Stress Fractures A Runners Nightmare should consult his or her general practitioner, physiotherapist, sports medicine specialist, orthopedic surgeon or otherwise appropriately skilled practitioner.