Chronic exertional compartment syndrome (CECS) was first described in 1956, 1 but little research has been performed since then to confirm the pathological physiology. An assumption is made that elevated subfascial or intramuscular pressure during exercise causes tissue hypoxia and subsequent ischaemic pain due to decreased blood flow. 2 To date, no conclusive evidence exists to demonstrate cellular hypoxic damage or decreased capillary perfusion. 3 Further supposition is made regarding muscle hypertrophy, reduced compartment volume due to a decreased fascial compliance, 4 and shorter periods of muscle relaxation as the underlying pathophysiology of CECS. There are many questions over whether the technique of intracompartmental pressure measurement is reliable. Examination of the widely accepted diagnostic criteria published in the seminal paper by Pedowitz et al5 reveals significant flaws, as the CECS and non-CECS groups were preselected by their differences in intramuscular pressure. We have also demonstrated significant overlap of the published diagnostic criteria for CECS with the published normative data. 6 Furthermore, intramuscular pressure measurement varies considerably with the depth of the catheter tip, the means of measurement and the mode of exercise. It is also important that the criteria presented are only applicable to the anterior compartment. CECS is also reported as being diagnosed in the deep posterior and peroneal compartments of the leg, 7 the foot8 and the forearm, 9 despite diagnostic pressure criteria never having been established in these other myofascial compartments. What is undeniable however is that exertional lower-limb symptoms localised to the myofacial compartments are commonly reported in elite and recreational athletes, 10 military personnel, 11 12 and non-athletes alike, 13 and that CECS is included in the differential diagnosis. As a tertiary referral centre for exertional leg pain, we have conducted large numbers (c. 100/year) of intracompartmental pressure measurements, often with subsequent referral for fasciotomy. 6 While short-term outcome following fasciotomy reflected published data14 15 we have found long-term outcome (> 12 months) to be disappointing, using objective measures. 16 Both the previously reported groups used athletes or adolescents as subjects and may differ in that the ‘return to play’criteria were less objective, which may explain the differences in outcome. Biomechanical factors have been shown to improve running economy. 17 In particular stride length, 18 ground contact time, vertical oscillation and lower extremity angles all have an effect on running efficiency. Despite this, recreational athletes and military recruits rarely receive training in running technique, either with verbal cues, video analysis or feedback as running is assumed to be a natural skill that man has acquired over several millennia. 19

During walking gait, tibialis anterior dorsiflexes the ankle concentrically to provide foot clearance during swing phase, and isometrically (with lengthening of the tendon) 20 to control the lowering of the forefoot during the first part of stance; this is assisted by the long-toe extensors (extensor hallucis longus, extensor digitorum longus) and peroneus tertius. During running gait, both the tibialis anterior and gastrocnemius have a high degree of preactivation prior to foot strike. 21 Tibialis anterior activity decreases more rapidly during running-induced metabolic fatigue, compared with the gastrocnemius. 22