Treatment of glenohumeral instability in rugby players

Rugby is a high-impact collision sport, with impact forces. Shoulder injuries are common and result in the longest time off sport for any joint injury in rugby. The most common injuries are to the glenohumeral joint with varying degrees of instability. The degree of instability can guide management. The three main types of instability presentations are: (1) frank dislocation, (2) subluxations and (3) subclinical instability with pain and clicking. Understanding the exact mechanism of injury can guide diagnosis with classical patterns of structural injuries. The standard clinical examination in a large, muscular athlete may be normal, so specific tests and techniques are needed to unearth signs of pathology. Taking these factors into consideration, along with the imaging, allows a treatment strategy. However, patient and sport factors need to be also considered, particularly the time of the season and stage of sporting career. Surgery to repair the structural damage should include all lesions found. In chronic, recurrent dislocations with major structural lesions, reconstruction procedures such as the Latarjet procedure yields better outcomes. Rehabilitation should be safe, goal-driven and athlete- specific. Return to sport is dependent on a number of factors, driven by the healing process, sport requirements and extrinsic pressures

Effect of acute hypoxia on respiratory muscle fatigue in healthy humans

<p>Abstract</p> <p>Background</p> <p>Greater diaphragm fatigue has been reported after hypoxic versus normoxic exercise, but whether this is due to increased ventilation and therefore work of breathing or reduced blood oxygenation per se remains unclear. Hence, we assessed the effect of different blood oxygenation level on isolated hyperpnoea-induced inspiratory and expiratory muscle fatigue.</p> <p>Methods</p> <p>Twelve healthy males performed three 15-min isocapnic hyperpnoea tests (85% of maximum voluntary ventilation with controlled breathing pattern) in normoxic, hypoxic (SpO₂= 80%) and hyperoxic (FiO₂= 0.60) conditions, in a random order. Before, immediately after and 30 min after hyperpnoea, transdiaphragmatic pressure (P_di,tw) was measured during cervical magnetic stimulation to assess diaphragm contractility, and gastric pressure (P_ga,tw) was measured during thoracic magnetic stimulation to assess abdominal muscle contractility. Two-way analysis of variance (time x condition) was used to compare hyperpnoea-induced respiratory muscle fatigue between conditions.</p> <p>Results</p> <p>Hypoxia enhanced hyperpnoea-induced P_di,twand P_ga,twreductions both immediately after hyperpnoea (P_di,tw: normoxia -22 ± 7% vs hypoxia -34 ± 8% vs hyperoxia -21 ± 8%; P_ga,tw: normoxia -17 ± 7% vs hypoxia -26 ± 10% vs hyperoxia -16 ± 11%; all <it>P </it>< 0.05) and after 30 min of recovery (P_di,tw: normoxia -10 ± 7% vs hypoxia -16 ± 8% vs hyperoxia -8 ± 7%; P_ga,tw: normoxia -13 ± 6% vs hypoxia -21 ± 9% vs hyperoxia -12 ± 12%; all <it>P </it>< 0.05). No significant difference in P_di,twor P_ga,twreductions was observed between normoxic and hyperoxic conditions. Also, heart rate and blood lactate concentration during hyperpnoea were higher in hypoxia compared to normoxia and hyperoxia.</p> <p>Conclusions</p> <p>These results demonstrate that hypoxia exacerbates both diaphragm and abdominal muscle fatigability. These results emphasize the potential role of respiratory muscle fatigue in exercise performance limitation under conditions coupling increased work of breathing and reduced O₂transport as during exercise in altitude or in hypoxemic patients.</p

A review of the anthropometric characteristics, grading and dispensation of junior and youth rugby union players in Australia

The grading of Australian junior and youth rugby union players has received substantial media attention in recent years. Media reports have focussed on size mismatches observed between players, especially players with Polynesian heritage, and the concerned parents who fear for the safety of their child owing to perceived mismatches. Although such concerns are well meaning, few media reports recognise the need for substantial evidence to determine the best grading system for junior and youth rugby union players. The current study reviewed relevant literature pertinent to the grading and dispensation of junior and youth rugby union players. Using primary and secondary search strategies, a total of 33 articles reporting the anthropometric characteristics of junior and youth rugby players were identified. Anthropometric data from the literature were compared with normative population data and currently used dispensation criteria. Junior and youth rugby players were found to be taller and heavier than normative population data. Current dispensation criteria, in terms of body mass, were found to vary and it is suggested that criteria be revised and standardised across rugby unions throughout Australia. Although it is acknowledged that other factors are important for grading players, anthropometric characteristics should be considered as potential dispensation criteria to supplement current age-based grading for junior and youth rugby union players. Measuring the body mass and stature of each junior player upon pre-season registration is suggested, which would provide data to establish valid dispensation criteria for the following season

Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions

International audienceThe PHENIX collaboration presents first measurements of low-momentum (0.41  GeV/c) direct-photon yield dNγdir/dη is a smooth function of dNch/dη and can be well described as proportional to (dNch/dη)α with α≈1.25. This scaling behavior holds for a wide range of beam energies at the Relativistic Heavy Ion Collider and the Large Hadron Collider, for centrality selected samples, as well as for different A+A collision systems. At a given beam energy, the scaling also holds for high pT (>5  GeV/c), but when results from different collision energies are compared, an additional sNN-dependent multiplicative factor is needed to describe the integrated-direct-photon yield