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Muscle injuries are among the most common injuries in sport and continue to be a major concern because of training and competition time loss, challenging decision making regarding treatment and return to sport, and a relatively high recurrence rate. An adequate classification of muscle injury is essential for a full understanding of the injury and to optimize its management and return-to-play process. The ongoing failure to establish a classification system with broad acceptance has resulted from factors such as limited clinical applicability, and the inclusion of subjective findings and ambiguous terminology. The purpose of this article was to describe a classification system for muscle injuries with easy clinical application, adequate grouping of injuries with similar functional impairment, and potential prognostic value. This evidence-informed and expert consensus-based classification system for muscle injuries is based on a four-letter initialism system: MLG-R, respectively referring to the mechanism of injury (M), location of injury (L), grading of severity (G), and number of muscle re-injuries (R). The goal of the classification is to enhance communication between healthcare and sports-related professionals and facilitate rehabilitation and return-to-play decision making.

Aims. Our main goals are to get a deeper insight into the evolution and final fates of intermediate-mass, extremely metal-poor (EMP) stars. We also aim to investigate the C, N, and O yields of these stars. Methods. Using the Monash University Stellar Evolution code MONSTAR we computed and analysed the evolution of stars of metallicity Z = 10 −5 and masses between 4 and 9 M , from their main sequence until the late thermally pulsing (super) asymptotic giant branch, TP-(S)AGB phase. Results. Our model stars experience a strong C, N, and O envelope enrichment either due to the second dredge-up process, the dredgeout phenomenon, or the third dredge-up early during the TP-(S)AGB phase. Their late evolution is therefore similar to that of higher metallicity objects. When using a standard prescription for the mass loss rates during the TP-(S)AGB phase, the computed stars are able to lose most of their envelopes before their cores reach the Chandrasekhar mass (m Ch ), so our standard models do not predict the occurrence of SNI1/2 for Z = 10 −5 stars. However, we find that the reduction of only one order of magnitude in the mass-loss rates, which are particularly uncertain at this metallicity, would prevent the complete ejection of the envelope, allowing the stars to either explode as an SNI1/2 or become an electron-capture SN. Our calculations stop due to an instability near the base of the convective envelope that hampers further convergence and leaves remnant envelope masses between 0.25 M for our 4 M model and 1.5 M for our 9 M model. We present two sets of C, N, and O yields derived from our full calculations and computed under two different assumptions, namely, that the instability causes a practically instant loss of the remnant envelope or that the stars recover and proceed with further thermal pulses. Conclusions. Our results have implications for the early chemical evolution of the Universe and might provide another piece for the puzzle of the carbon-enhanced EMP star problem.

Aims. We compute and analyze the evolution of primordial stars of masses at the ZAMS between 5 M and 10 M , with and without overshooting. Our main goals are to determine the nature of the remnants of massive intermediate-mass primordial stars and to check the influence of overshooting in their evolution. Methods. Our calculations cover stellar evolution from the main sequence phase until the formation of the degenerate cores and the thermally pulsing phase. Results. We have obtained the values for the limiting masses of Population III progenitor stars leading to carbon-oxygen and oxygenneon compact cores. Moreover, we have also obtained the limiting mass for which isolated primordial stars would lead to core-collapse supernovae after the end of the main central burning phases. Considering a moderate amount of overshooting, the mass thresholds at the ZAMS for the formation of carbon-oxygen and oxygen-neon degenerate cores shift to smaller values by about 2 M . As a by-product of our calculations, we have also obtained the structure and composition profiles of the resulting compact remnants. Conclusions.As opposed to what happens with solar metallicity objects, the final fate of primordial stars is not straightforwardly determined from the mass of the compact cores at the end of carbon burning. Instead, the small mass-loss rates typically associated with stellar winds of low metallicity stars might allow the growth of the resulting degenerate cores up to the Chandrasekhar mass, on time scales one or two orders of magnitude shorter than the time required to lose the envelope. This would lead to the formation of supernovae for initial masses as small as ∼5 M .