Shin Splints
Shin pain is one of the most common problems affecting active people, particularly runners, military personal, and field/court sports that involve rapid acceleration, change of direction and jumping. Current literature states 13.6% – 20% of runners are experiencing some type of shin pain at any given time(Hamstra-Wright, Bliven, & Bay, 2017).
There are a number of injuries that occur in the lower leg and just about any pain below the knee will be referred to as shin splints! So let’s get some clarity on what we are dealing with.
The common injuries that are labelled under the broad term “shin splints” include: tendinopathies, periostitis, popliteal artery entrapment syndrome, stress reactions or fractures, and compartment syndrome (more recently referred to as chronic exertional overload syndrome or medial tibial stress syndrome MTSS). These are overuse injuries, usually caused by a combination of biomechanical issues, technical problems and training errors, which together affect a structure’s ability to tolerate loading. Once a anatomical structure has difficulty withstanding load, symptoms develop at the weakest point.
Tendinopathies
As anyone who has ever had the pleasure of a tendonopathy they are very painful and can result in a chronic degenerative condition specifically involving tendons. Research of high quantity is currently being performed to identify the mechanisms and physiological factors that contribute to the onset and continual progression of tendinopathies.
That being said, research has identified one very important aspect to aid the rehabilitation of tendons. This important aspect is, tendons are made to load, stretch to store energy and then release that energy quickly during powerful movements. For this reason, rehab must improve the tendons load bearing capacity.
It is thought that a poor healing response starts a process, in which small blood vessels (neovascular tissue) and nerves grow into the tendon. These are not normally present in tendons, and are thought to be a possible source of pain. There is normally a tender thickening in the area of the neovascular tissue, a spreading out of the weight bearing collagen fibres and on ultrasound scans small tears along the tendon can often be seen.
Periostitis
Periostitis is an inflammation of the membrane (periosteum) that covers the bone. The periosteum provides the attachment for muscle and tendons and is where we find the cells that lead the underlying bone to thicken and strengthen in response to loading. If repeated and excessive tension is placed through this insertion, the periosteum can become inflamed and painful. Periostitis cannot be observed on an X-ray until 4-6 weeks after the initial micro trauma has occurred. However you will feel the signs and symptoms of periostitis 3-4 weeks post-initial trauma (Franklyn, & Oakes, 2015). Therefore the combination of a clinical examination along with imaging is your best option to improve your recovery rate and return to your activity or sport of choice.
Popliteal Artery Entrapment Syndrome
An uncommon form of lower limb pain, however must be considered when individuals show signs of an overuse injury developing at or below the knee. Commonly coincides with compartment syndrome. The popliteal artery is compressed by the calf musculature resulting in constant aching, numbness, tiredness, heaviness, and out of characteristic number of cramps in the calf muscles.
Stress Fractures
Remodelling of bone is constantly taking place in response to loading. After exercise, bone-forming cells (osteoblasts) in the periosteum add minerals to the outside of the bone, while bone destroying cells (osteoclasts) absorb bone from the cavity inside of the bone creating a thicker stronger but light tube, similar to bike frames. In cases of excessive and prolonged overloading the osteoclasts may not switch off, leading to the continual breakdown rather than a strengthening of the bone. Small cracks can develop and are referred to as stress or fatigue fractures.
Females are especially at risk of developing stress fractures if training load is not progressed appropriately and/or specific to the individuals training history. Research has identified female runners who start training from a lower base of bone density being at considerable risk of developing a stress fracture. It is important for the individual and coach to consider the age of menarche (when menstration begins), menstrual disturbance, bone density, leg length discrepancy, muscle mass around the bone structures, and diet when planning training as these are all significant risk factors in developing bony stress (Newman et al., 2013). X-rays usually detect abnormalities after 2-8 weeks from initial symptom onset. MRI’s can be useful in picking up oedema related to bone injuries within 3 days of symptom onset (Brewer, & Gregory, 2012). Early detection allows an earlier change in load, and overall a much shorter full recovery.
Compartment Syndrome
Another less common condition which is thought to involve the connective tissue, the fascia, which covers the group of muscles in the calf or shin, failing to stretch as blood flow to the muscles increases during exercise. As the volume of blood in the muscle increases, so to does the pressure within the compartment. This increase in pressure restricts further blood flow into the compartment and the muscle is starved of oxygen leading to pain. Pain and tightness will develop during exercise and continue to worsen until activity stops. Multiple studies have shown that an increase in muscle volume up to 20% can occur when exercising compared to rest. The symptoms of compartment syndrome are felt in both lower limbs 70-80% of the time and involve pain, muscle tightness, and muscle dysfunction (Tucker, 2010).
In the past, cases of compartment syndrome were often sent for fasciotomies where the fascia, is sliced open to relieve the pressure. More recently it has been shown that reducing biomechanical loading with correction of running technique is extremely effective at resolving the condition.
Self-Treatment & Prevention Tips:
- Stretching-to reduce the tension in the muscles pulling at the insertions. This can be soothing but for lasting benefit the stretching needs to coupled with strengthening exercises.
- Exercise-this doesn’t just mean more of the same exercise that brings on your pain hoping that you get used to it. It means exercises to develop strength in the areas that aren’t coping with the exercise you’re doing so you tolerate the stress and don’t feel pain.
- Ice massage-Try massaging
with an ice cube in the tender area, but keep the ice moving to avoid ice burns.
- Self Massage– while typically less intense than massage received in treatment, self-massage on a daily basis compliments stretching to reduce muscle tightness.
- Rest is a relative term! It does depend on the diagnosis and the severity. Reductions in training volume or intensity can be enough to allow mild symptoms to ease and if not, more severe restrictions in activity up to complete rest to the injured area could be necessary, while treatment is undertaken. In this case cross training can prevent loss of strength and fitness. It’s important to keep in mind that rest does not address the underlying issues of weakness, muscle tightness and joint stiffness which contributes to development of the injury in the first place and in fact leads to further weakness and stiffness. When activity resumes, if these issues aren’t addressed, the pain often returns as well. Specific exercises should address these issues while load is controlled and progressed while training volumes are built up.
If pain resolves with rest but returns when normal training resumes then you are likely dealing with a situation where the biomechanics are the driving cause of the pain and conditioning is inadequate. This needs to be looked at by a physiotherapist and an appropriate conditioning program prescribed.
The Role of the Physio
Physiotherapy management of these injuries involves: massage, mobilisation of joint stiffness, biomechanical correction, strengthening, stretching, controlled re-loading, conditioning and working with coaches to manage cross training and return to full training. The primary risk factors your physiotherapist will take into account when diagnosing and treating your shin pain include, an increase in body mass index (BMI), navicular drop (bone located in the foot), ankle range of motion, hip range of motion, historical training load and previous injury and technique or running form.
Research gives strong support to the importance of technique in association with biomechanics and load modification in conjunction with a conditioning program to ensure adequate strength and control. Fine tuning running form with specific drills and exercise can greatly effect how you load the body and particularly the site of injury.
The earlier you recognize that the problem is persisting or worsening and seek assessment and treatment, the less likely you are to miss training or suffer prolonged pain.
Summary
There are a lot of variables and risk factors that must be considered when looking to reduce the risk of injury or when treating someone with shin pain.
The most significant risk factors that must be considered are; history of lower limb injuries, number of years training, gender, increased BMI, increased navicular drop and increased external rotation of hip ROM in males. Therefore individuals with many of these risk factors should be advised and monitored to reduce total impact loads and complete a more conservative build into training.
These conditions can be difficult to differentiate so it’s important to get an accurate diagnosis and a specific rehabilitation plan.
These self-management techniques are a guide and a good place to start but if reoccurring or persistent symptoms develop give us a call.
Resources:
Brewer, R. B., & Gregory, A. J. (2012). Chronic lower leg pain in athletes: a guide for the differential diagnosis, evaluation, and treatment. Sports Health, 4(2), 121-127.
Franklyn, M., & Oakes, B. (2015). Aetiology and mechanisms of injury in medial tibial stress syndrome: Current and future developments. World journal of orthopedics, 6(8), 577.
Hamstra-Wright, K. L., Bliven, K. C. H., & Bay, C. (2015). Risk factors for medial tibial stress syndrome in physically active individuals such as runners and military personnel: a systematic review and meta-analysis. Br J Sports Med, 49(6), 362-369.
Newman, P., Witchalls, J., Waddington, G., & Adams, R. (2013). Risk factors associated with medial tibial stress syndrome in runners: a systematic review and meta-analysis. Open access journal of sports medicine, 4, 229.
Tucker, A. K. (2010). Chronic exertional compartment syndrome of the leg. Current reviews in musculoskeletal medicine, 3(1-4), 32-37.
