Biomechanical Overload Syndrome (AKA Shin Splints)
Track & field season is nearly upon is here in South East Asia. Students from International School Bangkok, Singapore American School, International School Manila, Jakarta Intercultural School, Taipei American School and International School Kuala Lumpur will all butt heads (hopefully not literally) in Taipei at the end of March to compete for the shiny gold medals.
One of the most common injuries that these athletes will experience in the build up to this competition is the dreaded ‘shin splints’. This blog post will address this issue and try to shed some light on what this injury is and how it can be managed.
The musculature of the lower limb is designed to allow us to move by absorbing and producing force when landing, running and jumping. When these muscles get fatigued, they fail at their protective duties, causing stress. If this stress isn’t appropriately managed and the muscles are continuously loaded whilst fatigued, a bony overload may present which eventually can lead to the formation of stress fracture.
Conservative treatment of these pathologies is by no means straight forward, as foam rolling; stretching; acupuncture; icing; massage and shockwave therapy (especially shockwave therapy) have all proved to be only mildly successful (or not successful at all).
Furthermore, there is often confusion over terminology, with many athletes self-diagnosing what is a complicated pathology. Medical professionals & athletic trainers shouldn’t use the term ‘shin splints’, as this umbrella term is far too basic to accurately describe either the mechanism or associated symptoms. Saying that, one can certainly be forgiven for this over-simplification, as the literature is rather confusing and numerous terms are used, as well as general terms such as ‘overuse lower limb injury’ and ‘exertional lower limb pain’, there is also research which refers to shin pain as ‘medial tibial stress syndrome’ and ‘chronic exertional compartment syndrome’ (See table below).
Andy Franklyn-Miller – an authority in the field – has recommended that a new diagnosis which directly addresses the root cause of shin pain be swiftly adopted. The underlying mechanism for these symptoms of pain is muscular overload and therefore, the term Biomechanical Overload Syndrome (BOS) has been proposed.
What IS biomechanical overload syndrome?
Athletes will usually experience a gradual and progressive onset of pain, which will be felt either at a focal point on the medial / lateral tibial border or across the entire shin bone, with Athletes often describing this pain as ‘pressure’, ‘cramping’ or ‘tightening’. The table below gives some information on what may be causing these symptoms, however as we will discuss later; a thorough assessment of the lower leg will allow therapists to more accurately diagnose and address these symptoms.
Shin pain treatment and exercise programming is by no means easy, its therefore highly beneficial to be able to accurately diagnose this issue from the outset. Similar to CECS, symptoms of Biomechanical Overload Syndrome can present in various ‘compartments’, and rehabilitation will vary depending on which compartment is symptomatic.
Overuse of the ankle flexors (tibialis anterior) which dorsiflex the ankle and control the foot whilst it is in mid stance.
Poor gluteal activation in drive phase
Excessive heel strike with increased dorsiflexion of the ankle in terminal swing phase
Run with an upright body over the centre of mass with the pelvis in a neutral position
Emphasise a downward piston action of the leg to utilise the hip extensors
Run on mid-foot and avoid excessive heel strike
Overload of the medial soleus and tibialis posterior which can be partly attributed to a lack of forefoot pronation control.
Rapid rate of forefoot pronation can increase eccentric load of the planter flexors
Step width - any cross over of gait cycle reinforces rate of pronation and less eccentric control.
To reduce forefoot pronation and promote faster recruitment of the tibialis posterior, you can try to give the athlete a physical cue by placing a small rubber disc underneath the first metatarsal
Strengthen tibialis posterior and soleus to improve foot control
Overload of the gastrocnemius / soleus complex due to a repetitive stretch-contract cycle.
Prolonged ground contact times which increase time spent under loaded dorsiflexion.
This overloads the posterior compartment which can eventually result in a traction stress on the bone.
Rapid rate of pronation and loss of end-range plantar flexion strength
Coach a stiffer leg on ground contact to recruit posterior extensors rather than ankle plantar flexors
Coach a piston-like leg action, punching the foot into the ground and keeping the torso upright
Strengthen the gastroc / soleus complex
The most important thing to address with biomechanical overload syndrome (as a coach) is running technique, which should be broken down by systematically focussing on kinematics of the pelvis, knee, shin and foot. Andy Franklyn-Miller suggests that a walk-to-run programme may be beneficial whereby the athlete completes 30 minute running sessions. These sessions should be progressive in nature; for example, session 1 may consist of 4 minutes walking followed by 1 minute running to allow the athlete to concentrate on the coaching cues and run pain free. The ratio of walk to run should gradually increase until the athlete can complete 30 minutes of pain free running whilst demonstrating appropriate and newly learned running technique.
With adequate athlete preparation and skilled diagnosis and treatment, the prevalence of biomechanical overload syndrome in the athletic population can be managed. Attempts have been made to simplify terminology, which should limit the confusion surrounding this pathology and guide our rehabilitation programmes.
Franklyn-Miller, A., (2016). Sports Injury Prevention and Rehabilitation: Integrating medicine and science for performance solutions - The Athletic Shin. Routledge 337-345.
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