BackgroundHamstring injury is the single most common injury in professional football. MRI is commonly used to confi rm the diagnosis and provide a prognosis of lay-off time.Objective To evaluate the use of MRI as a prognostic tool for lay-off after hamstring injuries in professional football players and to study the association between MRI fi ndings and injury circumstances. Methods Prospective cohort study where 23 European professional teams, were followed between 2007 and 2011. Team medical staffs recorded individual player exposure and time-loss injuries. Radiological grading was performed using a modifi ed Peetrons classifi cation into four grades where grades 2 and 3 represent fi bre disruption. Results In total, 516 hamstring injuries occurred and 58% of these were examined by MRI. Thirteen per cent were grade 0 injuries, 57% grade 1, 27% of grade 2 and 3% of grade 3. Grade 0 and 1 injuries accounted for 56% (2141/3830 days) of the total lay-off. The layoff time differed between all four radiological grades of injury (8±3, 17±10, 22±11 and 73±60 days, p<0.0001). Eighty-three per cent of injuries affected the biceps femoris while 11% and 5% occurred to the semimembranosus and semitendinosus, respectively. Re-injuries (N=34/207) constituted 16% of injuries. All re-injuries occurred to the biceps femoris. Conclusion MRI can be helpful in verifying the diagnosis of a hamstring injury and to prognosticate layoff time. Radiological grading is associated with lay-off times after injury. Seventy per cent of hamstring injuries seen in professional football are of radiological grade 0 or 1, meaning no signs of fi bre disruption on MRI, but still cause the majority of absence days.

ObjectiveTo provide a clear terminology and classification of muscle injuries in order to facilitate effective communication among medical practitioners and development of systematic treatment strategies.MethodsThirty native English-speaking scientists and team doctors of national and first division professional sports teams were asked to complete a questionnaire on muscle injuries to evaluate the currently used terminology of athletic muscle injury. In addition, a consensus meeting of international sports medicine experts was established to develop practical and scientific definitions of muscle injuries as well as a new and comprehensive classification system.ResultsThe response rate of the survey was 63%. The responses confirmed the marked variability in the use of the terminology relating to muscle injury, with the most obvious inconsistencies for the term strain. In the consensus meeting, practical and systematic terms were defined and established. In addition, a new comprehensive classification system was developed, which differentiates between four types: functional muscle disorders (type 1: overexertion-related and type 2: neuromuscular muscle disorders) describing disorders without macroscopic evidence of fibre tear and structural muscle injuries (type 3: partial tears and type 4: (sub)total tears/tendinous avulsions) with macroscopic evidence of fibre tear, that is, structural damage. Subclassifications are presented for each type.ConclusionsA consistent English terminology as well as a comprehensive classification system for athletic muscle injuries which is proven in the daily practice are presented. This will help to improve clarity of communication for diagnostic and therapeutic purposes and can serve as the basis for future comparative studies to address the continued lack of systematic information on muscle injuries in the literature.What are the new thingsConsensus definitions of the terminology which is used in the field of muscle injuries as well as a new comprehensive classification system which clearly defines types of athletic muscle injuries.Level of evidenceExpert opinion, Level V.

This article reviews the clinical, anatomical, and biomechanical basis of pubalgia and relates it to the potential imaging findings and subsequent management. Although the magnetic resonance imaging features typically seen in symptomatic athletes are emphasized, this condition remains a complex clinical problem, and treatment addressing the functional rehabilitation of the entire region is highlighted.

Case series, Level IV.