Ready for impact? A validity and feasibility study of instrumented mouthguards (iMGs)

Objectives Assess the validity and feasibility of current instrumented mouthguards (iMGs) and associated systems. Methods Phase I; four iMG systems (Biocore-Football Research Inc (FRI), HitIQ, ORB, Prevent) were compared against dummy headform laboratory criterion standards (25, 50, 75, 100 g). Phase II; four iMG systems were evaluated for on-field validity of iMG-triggered events against video-verification to determine true-positives, false-positives and false-negatives (20±9 player matches per iMG). Phase III; four iMG systems were evaluated by 18 rugby players, for perceptions of fit, comfort and function. Phase IV; three iMG systems (Biocore-FRI, HitIQ, Prevent) were evaluated for practical feasibility (System Usability Scale (SUS)) by four practitioners. Results Phase I; total concordance correlation coefficients were 0.986, 0.965, 0.525 and 0.984 for Biocore-FRI, HitIQ, ORB and Prevent. Phase II; different on-field kinematics were observed between iMGs. Positive predictive values were 0.98, 0.90, 0.53 and 0.94 for Biocore-FRI, HitIQ, ORB and Prevent. Sensitivity values were 0.51, 0.40, 0.71 and 0.75 for Biocore-FRI, HitIQ, ORB and Prevent. Phase III; player perceptions of fit, comfort and function were 77%, 6/10, 55% for Biocore-FRI, 88%, 8/10, 61% for HitIQ, 65%, 5/10, 43% for ORB and 85%, 8/10, 67% for Prevent. Phase IV; SUS (preparation-management) was 51.3-50.6/100, 71.3-78.8/100 and 83.8-80.0/100 for Biocore-FRI, HitIQ and Prevent. Conclusion This study shows differences between current iMG systems exist. Sporting organisations can use these findings when evaluating which iMG system is most appropriate to monitor head acceleration events in athletes, supporting player welfare initiatives related to concussion and head acceleration exposure.</p

Changes in adductor strength after competition in Academy Rugby Union Players

© 2016 National Strength and Conditioning Association. This study determined the magnitude of change in adductor strength after a competitive match in academy rugby union players and examined the relationship between locomotive demands of match-play and changes in postmatch adductor strength. A withinsubject repeated measures design was used. Fourteen academy rugby union players (age, 17.4 ± 0.8 years; height, 182.7 ± 7.6 cm; body mass, 86.2 ± 11.6 kg) participated in the study. Each player performed 3 maximal adductor squeezes at 458 of hip flexion before and immediately, 24, 48, and 72 hours postmatch. Global positioning system was used to assess locomotive demands of match-play. Trivial decreases in adductor squeeze scores occurred immediately (21.3 ± 2.5%; effect size [ES] = 20.11 ± 0.21; likely, 74%) and 24 hours after match (20.7 ± 3%; ES = 20.06 ± 0.25; likely, 78%), whereas a small but substantial increase occurred at 48 hours (3.8 ± 1.9%; ES = 0.32 ± 0.16; likely, 89%) before reducing to trivial at 72 hours after match (3.1 ± 2.2%; ES = 0.26 ± 0.18; possibly, 72%). Large individual variation in adductor strength was observed at all time points. The relationship between changes in adductor strength and distance covered at sprinting speed (VO2max 81%) was large immediately postmatch (p = 0.056, r = 20.521), moderate at 24 hours (p = 0.094, r = 20.465), and very large at 48 hours postmatch (p = 0.005, r = 20.707). Players who cover greater distances sprinting may suffer greater adductor fatigue in the first 48 hours after competition. The assessment of adductor strength using the adductor squeeze test should be considered postmatch to identify players who may require additional rest before returning to field-based training

Implementation of the 2017 Berlin Concussion in Sport Group Consensus Statement in contact and collision sports : a joint position statement from 11 national and international sports organisations

The 2017 Berlin Concussion in Sport Group Consensus Statement provides a global summary of best practice in concussion prevention, diagnosis and management, underpinned by systematic reviews and expert consensus. Due to their different settings and rules, individual sports need to adapt concussion guidelines according to their specific regulatory environment. At the same time, consistent application of the Berlin Consensus Statement’s themes across sporting codes is likely to facilitate superior and uniform diagnosis and management, improve concussion education and highlight collaborative research opportunities. This document summarises the approaches discussed by medical representatives from the governing bodies of 10 different contact and collision sports in Dublin, Ireland in July 2017. Those sports are: American football, Australian football, basketball, cricket, equestrian sports, football/soccer, ice hockey, rugby league, rugby union and skiing. This document had been endorsed by 11 sport governing bodies/national federations at the time of being published.http://bjsm.bmj.comhj2018Sports Medicin

Memory as acquaintance with the past: some Lessons from Russell, 1912-1914

Russell's theory of memory as acquaintance with the past seems to square uneasily with his definition of acquaintance as the converse of the relation of presentation of an object to a subject. We show how the two views can be made to cohere under a suitable construal of 'presentation', which has the additional appeal of bringing Russell's theory of memory closer to contemporary views on direct reference and object-dependent thinking than is usually acknowledged. The drawback is that memory as acquaintance with the past falls short of fulfilling Russell's requirement that knowledge by acquaintance be discriminating knowledge - a shortcoming shared by contemporary externalist accounts of knowledge from memory.A teoria russelliana da memória como contato (acquaintance) com o passado parece coadunar-se mal com definição do contato (acquaintance) como a conversa da relação de apresentação de um objeto a um sujeito. Mostramos como as duas concepções podem ser conciliadas mediante uma interpretação apropriada de 'apresentação', que tem a vantagem adicional de salientar uma proximidade maior que a usualmente reconhecida entre a teoria da memória de Russell e idéias contemporâneas sobre referência direta e pensamentos dependentes de objeto. O preço a pagar é o reconhecimento de que a memória como contato (acquaintance) com o passado não satisfaz o requisito russelliano de que o conhecimento por contato deva ser discriminativo - uma limitação que é compartilhada pelas abordagens externalistas contemporâneas do conhecimento derivado da memória

The View from Nowhen: The Mctaggart-Dummett Argument for the Unreality of Time

Years ago, Michael Dummett defended McTaggart’s argument for the unreality of time, arguing that it cannot be dismissed as guilty of an “indexical fallacy.” Recently, E. J. Lowe has disputed Dummett’s claims for the cogency of the argument. I offer an elaboration and defense of Dummett’s interpretation of the argument (though not of its soundness). I bring to bear some work on tense from the philosophy of language, and some recent work on the concept of the past as it occurs in memory, in an effort to support the claim that McTaggart is not guilty of any simple indexical fallacy. Along the way I criticize an account of what is at stake in disputes about the reality of tense due to A. W. Moore, and I argue for the superiority of the conception of tense-realism that is implicit in McTaggart’s work. The paper is intended to prepare the ground for a substantive defense of the reality of tense

The View from Nowhen: The Mctaggart-Dummett Argument for the Unreality of Time

Years ago, Michael Dummett defended McTaggart’s argument for the unreality of time, arguing that it cannot be dismissed as guilty of an “indexical fallacy.” Recently, E. J. Lowe has disputed Dummett’s claims for the cogency of the argument. I offer an elaboration and defense of Dummett’s interpretation of the argument (though not of its soundness). I bring to bear some work on tense from the philosophy of language, and some recent work on the concept of the past as it occurs in memory, in an effort to support the claim that McTaggart is not guilty of any simple indexical fallacy. Along the way I criticize an account of what is at stake in disputes about the reality of tense due to A. W. Moore, and I argue for the superiority of the conception of tense-realism that is implicit in McTaggart’s work. The paper is intended to prepare the ground for a substantive defense of the reality of tense

Ready for Impact? A validity and feasibility study of instrumented mouthguards (iMGs)

Objectives Determine the validity and feasibility of current Instrumented mouthguards (iMGs) and associated systems.Methods Phase 1; Four iMG systems (Football Research Inc [FRI], HitIQ, ORB, Prevent) were compared against dummy headform laboratory criterion standards (25, 50, 75, 100 g). Phase 2; Four iMG systems were evaluated for on-field validity of iMG-triggered events against video-verification to determine true-positives, false-positives and false-negatives (20 ± 9 player matches per iMG). Phase 3; Four iMG systems were evaluated by eighteen rugby players, for perceptions of fit, comfort and function. Phase 4; Three iMG systems (FRI, HitIQ, Prevent) were evaluated for practical feasibility (system usability scale; SUS) by four practitioners.Results Phase 1; Total concordance correlation coefficient was 98.3%, 95.3%, 42.5% and 97.9% for FRI, HitIQ, ORB and Prevent. Phase 2; Different on-field kinematics were observed between iMGs. Positive predictive values were 0.98, 0.90, 0.53 and 0.94 for FRI, HitIQ, ORB and Prevent. Sensitivity values were 0.51, 0.40, 0.71 and 0.75 for FRI, HitIQ, ORB and Prevent. Phase 3; player perceptions of fit, comfort and function were 77%, 6/10, 55% for FRI, 88%, 8/10, 61% for HitIQ, 65%, 5/10, 43% for ORB, and 85%, 8/10, 67% for Prevent. Phase 4; SUS was 51.3-50.6/100, 71.3-78.8/100, and 83.8-80.0/100 for FRI, HitIQ, and Prevent.Conclusion This study shows that differences between current iMG systems exist. Sporting organisations can use these findings to ensure accurate head acceleration event data are obtained and system adoption is optimized, to support player welfare initiatives directly related to long-term brain health

Ready for impact? A validity and feasibility study of instrumented mouthguards (iMGs)

Objectives Assess the validity and feasibility of current instrumented mouthguards (iMGs) and associated systems. Methods Phase I" four iMG systems (BiocoreFootball Research Inc (FRI), HitIQ, ORB, Prevent) were compared against dummy headform laboratory criterion standards (25, 50, 75, 100 g). Phase II" four iMG systems were evaluated for on-field validity of iMG-triggered events against video-verification to determine true-positives, false-positives and falsenegatives (20±9 player matches per iMG). Phase III" four iMG systems were evaluated by 18 rugby players, for perceptions of fit, comfort and function. Phase IV" three iMG systems (Biocore-FRI, HitIQ, Prevent) were evaluated for practical feasibility (System Usability Scale (SUS)) by four practitioners. Results Phase I" total concordance correlation coefficients were 0.986, 0.965, 0.525 and 0.984 for Biocore-FRI, HitIQ, ORB and Prevent. Phase II" different on-field kinematics were observed between iMGs. Positive predictive values were 0.98, 0.90, 0.53 and 0.94 for Biocore-FRI, HitIQ, ORB and Prevent. Sensitivity values were 0.51, 0.40, 0.71 and 0.75 for Biocore-FRI, HitIQ, ORB and Prevent. Phase III" player perceptions of fit, comfort and function were 77%, 6/10, 55% for Biocore-FRI, 88%, 8/10, 61% for HitIQ, 65%, 5/10, 43% for ORB and 85%, 8/10, 67% for Prevent. Phase IV" SUS (preparation-management) was 51.3–50.6/100, 71.3–78.8/100 and 83.8–80.0/100 for Biocore-FRI, HitIQ and Prevent. Conclusion This study shows differences between current iMG systems exist. Sporting organisations can use these findings when evaluating which iMG system is most appropriate to monitor head acceleration events in athletes, supporting player welfare initiatives related to concussion and head acceleration exposure