Post-Activation Performance Enhancement of Punch Force and Neuromuscular Performance in Amateur Boxing: Toward a More Individualized and "Real-World" Approach.

ABSTRACT: Finlay, MJ, Greig, M, Bridge, CA, and Page, RM. Post-activation performance enhancement of punch force and neuromuscular performance in amateur boxing: Toward a more individualized and "real-world" approach. J Strength Cond Res 38(6): 1063-1071, 2024-Previous research on post-activation performance enhancement has been applied in several sporting settings, although this is lacking in a boxing setting. This study explored the effectiveness of 2 upper-body conditioning activities in improving punch-specific performance during an amateur boxing-simulated bout. On 3 separate occasions, 10 male senior elite amateur boxers performed the following conditioning activities before a boxing-specific simulation protocol: isometric (ISO) punch, elastic resistance (ER) punch, and a control trial. Boxers performed maximal punches against a vertically mounted force plate, and countermovement jumps (CMJ) at baseline, before round 1, after each round, and 4 minutes after the simulation. Both conditioning activities, but not the control trial, produced small worthwhile increases (effect size ≥ 0.20; equal to or greater than the smallest worthwhile change) in punch force, although worthwhile increases in rate of force development were limited to the cross during the ISO trial. No group-based improvements in CMJ performance were observed. Individual analysis revealed that 6 boxers improved punch-specific performance to the greatest extent in the ISO trial; in contrast, only 1 boxer did so in the ER trial. Three boxers exhibited similar performance increases across trials. In conclusion, both conditioning activities may be applied to an amateur boxer's warm-up to acutely enhance punch-specific performance. The ISO conditioning activity seems most effective; however, the interindividual variability suggests a need for protocols to be individualized to each athlete. The conditioning activities in the present study may be applied to sparring, competitive bouts, or to other combat sports.

Acute effects of caffeine supplementation on taekwondo performance: the influence of competition level and sex.

The purpose of this study was to assess the effects of acute caffeine supplementation on physical performance and perceived exertion during taekwondo-specific tasks in male and female athletes with varying expertise. In a double-blinded, randomized, placebo-controlled crossover study design, 52 young athletes from elite (n = 32; 16 males and 16 females) and sub-elite competitive level (n = 20; 10 males and 10 females) participated. Athletes performed taekwondo-specific tasks including the taekwondo-specific agility test (TSAT), 10 s frequency speed of kick test (FSKT-10 s) and multi-bout FSKT (FSKT-multi) under the following conditions: (1) Caffeine (CAF; 3 mg kg-1), placebo (PLA), and no supplement control (CON). Session rating of perceived exertion (s-RPE) was determined after the tests. Findings show that regardless of condition, males performed better than females (p < 0.05) and elite athletes had superior performance compared to their sub-elite counterparts (p < 0.05). For the TSAT (p < 0.001), FSKT-10s (p < 0.001), and FSKT-multi (p < 0.001), CAF enhanced performance in elite female athletes compared to sub-elite females. Likewise, CAF ingestion resulted in superior performance in elite males compared to sub-elite males for FSKT-10s (p = 0.003) and FSKT-multi (p < 0.01). The ergogenic potential of CAF during taekwondo-specific tasks appears to be related to a competitive level, with greater benefits in elite than sub-elite athletes.

Test-retest reliability and sensitivity of senior elite amateur boxers maximal punch force, as quantified by a vertically mounted force plate.

An ecologically valid, reliable and sensitive method of quantifying punch force variables would be useful for coaches and practitioners monitoring combat-specific performance. The present study utilised a vertically mounted force plate to quantify the peak punch force and rate of force development (RFD) of amateur boxers. Ten male senior elite amateur boxers performed maximal jab, cross, and hook punches across two separate days. The force plate showed excellent within-day and good-to-excellent between-day reliability for peak punch impact force and RFD (ICC 0.89-0.99). The CV% for all punch force variables were similar on day 1 (3-9%) and day 2 (4-10%). Standard error of measurement (SEM) and smallest worthwhile changes (SWC) revealed the force plate can detect small-to-moderate changes in punch performance. The greatest impact forces and RFD were found in the rear hook (2624 ± 581 N, 296448 ± 101823 N.s-1), followed by the lead hook (2524 ± 532 N, 256813 ± 81735 N.s-1), cross 2425 ± 545 N, 193004 ± 62671 N.s-1) and jab (1645 ± 537 N, 116675 ± 41577 N.s-1). The vertically mounted force plate is a reliable and sensitive test of punch performance, thus may be useful in determining the efficacy of training interventions.

Effects of conditioning activity mode, rest interval and effort to pause ratio on post-activation performance enhancement in taekwondo: a randomized study.

Introduction: The present study assessed the effects of conditioning activities, using different effort-to-pause ratios and rest intervals, on taekwondo physical performance. Methods: Twenty-one athletes (13 males and 8 females) (Mean ± SD; age = 20.4 ± 1.4 years) performed a control (CC) and twelve experimental conditions. Each condition contained a standard warm-up (i.e., CC: running at 9 km/h for 10 min) and conditioning activities comprising plyometrics P) or repeated high-intensity techniques (RT) using 1:6, 1:9 and self-selected rest (SSR) ratios, and two rest intervals (3 and 7 min). Athletes then performed a battery of fitness tests: countermovement jump (CMJ), taekwondo specific agility (TSAT), 10s and multiple frequency speed kick test (FSKT-10s and FSKT-mult, respectively). Results: All of the preloads provided higher performance outputs compared to the control trial (all p < 0.05). For CMJ, 1:6 ratio with 3 min induced lower values with RT compared to P (p = 0.037) and 1:9 ratio using 3 min induced higher values with RT compared to P (p = 0.027). Additionally, 1:6 ratio using 7 min induced higher values with RT compared to P (p = 0.016). For FSKT-10, 3 min using 1:6 induced higher values with P compared to RT, while RT induced higher values with 7 min using 1:6 ratio compared to P (both p < 0.001). Moreover, 3 min using 1:9 ratio induced higher values with P compared to RT (p = 0.034), while RT induced higher values with 1:9 ratio using 7 min compared to P (p < 0.001). Finally, 3 min using SSR ratio induced higher values with RT compared to P (p = 0.034). Conclusion: Plyometrics and RT activities improved performance with plyometrics requiring shorter rest interval to induce potentiation effects compared to RT, which required longer interval.

Repeated High-Intensity Technique Training and Repeated Sprint Training Elicit Similar Adjustment in Physiological Responses But Divergent Perceptual Responses and Combat-Related Performances in Adolescent Taekwondo Matches.

PURPOSE: This study investigated the effects of 4 weeks of repeated sprint training (RST) versus repeated high-intensity technique training (RTT) on the physiological responses (ie, blood lactate), mean and peak heart rate, rating of perceived exertion, technical-tactical performance, and time-motion variables during simulated taekwondo combats. METHODS: Twenty-four taekwondo athletes (18 male and 6 female; age: 16 [1] y) were randomly and equally assigned to RST (10 × 35-m running sprints interspersed by 10-s rest) or RTT (10 × 6-s bandal-tchagui kicking executions interspersed by 10-s rest) groups in addition to their regular training. Both groups performed simulated combats before and after training. RESULTS: Delta lactate and peak heart rate were attenuated following training (P < .001 and P = .03, respectively), with no differences identified between RTT and RST conditions. Rating of perceived exertion decreased after training only in the RTT (P = .002). Time fighting and preparatory activities increased following training (P < .001), with higher values observed following RTT than RST (P < .001). Nonpreparatory time decreased after training (P < .001), with more pronounced reductions observed following RTT when compared to RST (P < .001). The number of single attacks decreased only following RST (P < .001), whereas combined attacks increased only after RTT training (P < .001). CONCLUSIONS: Similar adjustments in the physiological responses to combat were observed following 4 weeks of either RST or RTT, but RTT elicited more favorable perceptual responses and combat-related performance. This highlights the importance of specificity of training and its effective transfer to combat.

Challenges and considerations for reproducibility of STARR-seq assays.

High-throughput methods such as RNA-seq, ChIP-seq, and ATAC-seq have well-established guidelines, commercial kits, and analysis pipelines that enable consistency and wider adoption for understanding genome function and regulation. STARR-seq, a popular assay for directly quantifying the activities of thousands of enhancer sequences simultaneously, has seen limited standardization across studies. The assay is long, with more than 250 steps, and frequent customization of the protocol and variations in bioinformatics methods raise concerns for reproducibility of STARR-seq studies. Here, we assess each step of the protocol and analysis pipelines from published sources and in-house assays, and identify critical steps and quality control (QC) checkpoints necessary for reproducibility of the assay. We also provide guidelines for experimental design, protocol scaling, customization, and analysis pipelines for better adoption of the assay. These resources will allow better optimization of STARR-seq for specific research needs, enable comparisons and integration across studies, and improve the reproducibility of results.

Listening to Preferred and Loud Music Enhances Taekwondo Physical Performances in Adolescent Athletes.

In this study, we aimed to investigate the effects of warm-up music preference and loudness on physical performance, perceived exertion (RPE), and enjoyment in young taekwondo athletes. In a crossover counterbalanced design, 20 taekwondo athletes (10 male, 10 female) performed a battery of physical tasks specific to taekwondo under the following five conditions: (a) No music (NM), (b) Preferred music-Soft (60 dB; PMS), (c) Preferred music-Loud (80 dB; PML), (d) Non-preferred music-Soft (60 dB; NPMS), and (e) Non-preferred music-Loud (80 dB; NPML). On each lab visit, participants completed a taekwondo-specific agility test (TSAT), a10-second kick test (KSKT-10s) and a multiple frequency speed of kick tests (FSKT) within each music condition. Pre-exercise enjoyment was assessed using the Physical Activity Enjoyment Scale (PACES) after the warm-up, while we obtained RPE scores after each test. The PML condition resulted in significantly better agility test times on the TSAT compared to PMS (p < .001), and NPML (p < .001). Furthermore, PML led to a greater number of total kicks during the FSKT-10s test compared to the PMS (p < .001), and NPML (p < .001) conditions. The decrement index on the FSKT was lower in PML than in PMS and NPML conditions (p < .001). For RPE, values were significantly lower with preferred than non-preferred music (p < .001). These findings lend support to ergogenic benefits of listening to PML prior to taekwondo physical tasks, with important implications for enhancing taekwondo training and performance.

The prevalence of pre-conditioning and recovery strategies in senior elite and non-elite amateur boxing.

OBJECTIVES: A variety of acute strategies around competition are used to prepare and promote physical and mental restoration in athletes. However, to date, no research exists on the prevalence of such methods in amateur boxing. Therefore, this study aimed to 1) examine the prevalence of pre-conditioning and recovery strategies in amateur boxing; 2) ascertain whether this was discriminated against at competitor level. METHODS: This study surveyed 101 senior amateur boxers (Senior Elite SEB n = 59; Senior Development SDB n = 42), on their application and perceptions of pre-conditioning and recovery strategies. RESULTS: The reported findings determined a significantly greater number of SEB performed resistance priming activity up to 48 hours prior to competition (11, 19% vs 2, 5%; P = 0.040), and post-activation performance enhancement (PAPE) activity in the pre-competition warm-up (18, 31% vs 1, 2%; P < 0.001), compared to SDB. Likewise, SEB reported they were also significantly more likely to utilize massage (SEB 35, 59%, SDB 11, 29%, P = 0.001) and cold-water immersion (CWI) (SEB 28, 47%, SDB 10, 29%, P = 0.016) as recovery modes, compared to their SDB counterparts. CONCLUSIONS: This study was the first to provide data on the use of PAPE, priming and recovery methods around amateur boxing bouts. Increased access to multi-disciplinary staff could be expected in SEB, possibly explaining the greater prevalence of evidence-based methods around competition. Once athlete responsiveness to PAPEand longer-term priming methods are initially assessed, these strategies could be implemented to improve punch-specific performance, though more research is needed on their efficacy. Likewise, boxers could utilize evidence-based recovery modes where possible, with increased importance during repeat-bout scenarios, such as domestic tournaments. Coaches and practitioners may use this data to implement pre-conditioning and recovery strategies, to optimize performance and reduce the risk of injury of amateur boxers.

Relationship Between Intraoperative Electrocochleography and Hearing Preservation.

OBJECTIVES: To compare intraoperative intracochlear electrocochleography (ECochG) with hearing preservation outcomes in cochlear implant (CI) subjects. DESIGN: Intraoperative electrocochleography was performed in adult CI subjects who were recipients of Advanced Bionics' Bionics LLC precurved HiFocus MidScala or straight HiFocus SlimJ electrode arrays. ECochG responses were recorded from the most apical electrode contact during insertion. No changes to the insertions were made due to ECochG monitoring. No information about insertion resistance was collected. ECochG drops were estimated as the change in amplitude from peak (defined as maximum amplitude response) to drop (largest drop) point after the peak during insertion was measured following the peak response. Audiometric thresholds from each subject were obtained before and approximately 1 month after CI surgery. The change in pure tone average for frequencies between 125 Hz and 500 Hz was measured after surgery. No postoperative CT scans were collected as part of this study. RESULTS: A total of 68 subjects from five surgical centers participated in the study. The study sample included 30 MidScala and 38 SlimJ electrodes implanted by approximately 20 surgeons who contributed to the study. Although a wide range of results were observed, there was a moderate positive correlation (Pearson Correlation coefficient, r = 0.56, p < 0.01) between the size of the ECochG drop and the magnitude of pure tone average change. This trend was present for both the MidScala and SlimJ arrays. The SlimJ and MidScala arrays produced significantly different hearing loss after surgery. CONCLUSION: Large ECochG amplitude drops observed during electrode insertion indicated poorer hearing preservation. Although the outcomes were variable, this information may be helpful to guide surgical decision-making when contemplating full electrode insertion and the likelihood of hearing preservation.

Upper-Body Post-activation Performance Enhancement for Athletic Performance: A Systematic Review with Meta-analysis and Recommendations for Future Research.

BACKGROUND: Research on post-activation performance enhancement (PAPE) is dominated by lower-body conditioning activities/performance test complexes. Despite the contribution of the upper body to many sporting actions, no review on upper-body PAPE currently exists. OBJECTIVES: The aim of this systematic review with meta-analysis was to provide a synthesis of the available research on the inclusion of upper-body PAPE conditioning activities to improve athletic performance. METHODS: A review of the literature was conducted according to the Preferred Reporting Items for Systematic Review and Meta-analyses guidelines, including a literature search of EBSCOhost, SPORTDiscus, PubMed and Google Scholar databases. A total of 127 studies were identified through database searches, and were assessed against the following criteria: (1) randomised controlled trial or pre-and-post study design; (2) studies explored the effects of prior voluntary muscle activity, and not electrically induced contractions, (3) evidence, or lack thereof, of PAPE was quantified by the monitoring of individual performance to commonly applied physical tests or sport-specific tasks; (4) conditioning activities and performance tests were primarily upper-body; (5) detailed description of a standardised warm-up; and (6) full-text versions of studies could be accessed in English language peer-reviewed journals. Studies were quality assessed for methodological quality via the PEDro scale and ranked accordingly. RESULTS: Thirty-one studies met the inclusion criteria. Studies were classified into different conditioning activity modes: bench press variations, sport-specific (modified implement throws, swing-specific, cable pulley, elastic resistance, combination) and bodyweight activity. Acute performance enhancement in several movement-specific combinations was found. A meta-analysis revealed that bench press at ≥ 80% one repetition maximum significantly (p = 0.03; ES = 0.31) improves subsequent power output in the ballistic bench throw at 30-40% one repetition maximum, following 8-12 min recovery. Additionally, sport-specific overweight implement throws improved subsequent throwing distance at competition weight by ~ 1.7-8.5%; ES = 0.14-0.33, following 3 min recovery. Sport-specific lighter weighted bat swings and swing-specific isometrics resulted in improved subsequent competition weight bat swing velocities, ranging from ~ 1.3-4.9%; ES = 0.16-0.57. CONCLUSIONS: This review presents several upper-body movement-specific conditioning activities that could be considered by coaches and practitioners as part of complex or contrast training, or used in pre-competition warm-ups to acutely enhance performance.

The association between competitor level and the physical preparation practices of amateur boxers.

Physical training, testing, and monitoring are three key constitutes of athlete physical performance; however, there is a currently a lack of information on the prevalence of such methods in amateur boxing. This study aimed to explore the physical preparation practices of senior elite (SEB) and senior development (SDB) amateur boxers, and to determine whether these practices were discriminated by competitor level. One hundred and one amateur boxers (SEB n = 59, SDB n = 42) were surveyed on their understanding, perceptions and application of physical training, monitoring, and testing practices. SEB were associated with strength/power training (SEB 78%, SDB 50%, P = 0.005), monitor of training intensities (SEB 68%, SDB 40%, P = 0.006), and performing regular fitness testing (SEB 76%, SDB 50%, P = 0.006), compared to SDB. Likewise, SEB were twice as likely (56%) to have their physical preparation managed by a strength and conditioning (S&C) coach or sport scientist, compared to SDB (26%; P = 0.005). For the first time, these data demonstrate the extent to which competitor level is associated with preparatory practices in amateur boxing. Cost was identified as the main barrier in implementing several forms of scientific support in SDB. These data serve as a framework to enhance preparatory practices across different competitor levels in amateur boxing. This might include boxer and coach education on the benefits to a more scientific approach, and the use of cost-effective methods to develop, monitor and assess amateur boxers physical performance. This may be of particular importance where boxers are not funded, such as the SDB in the current study. However, this work may also be used to emphasise the importance of strength/power training, physical fitness testing and monitoring at the elite level of amateur boxing.

Recolonization by Slugs: Vertical and Horizontal Dispersal by the Field Slug, Deroceras reticulatum.

Following treatment with molluscicides or other controls, slugs can recolonize a site very quickly, but the proportion of the colonizing slugs moving from adjacent areas (horizontal dispersal) and the proportion from within the soil (vertical dispersal) has not previously been established. At a grassland site, barriers were used to exclude and trap slugs in order to estimate horizontal and vertical movement over a period of 32 months. For the first 15 months vertical movement made a significant contribution to the slugs recolonizing a grassland area. The ecological mechanisms occurring and the implications for the control of slugs are discussed.

Comparison of the use of wireless capsule endoscopy with magnetic resonance enterography in children with inflammatory bowel disease.

BACKGROUND: Magnetic resonance enterography (MRE) and wireless capsule endoscopy (WCE) are equally accepted modalities for noninvasive screening of small bowel involvement (SBI) in children with Crohn's disease (CD) and indeterminate colitis (IC) albeit there is a paucity of data comparing the two and thereby guiding the clinician in selecting the ideal diagnostic approach. Therefore, the goal of this study is to provide additional evidence for capsule endoscopy role in the evaluation of established Crohn's disease exacerbation compared to MRE in relation to Pediatric Crohn's Disease Activity Index (PCDAI), and histological indices. AIM: To prospectively compare the findings of MRE and WCE and their agreement with PCDAI or histology in children with CD or IC. METHODS: Consecutive patients diagnosed with CD and IC were screened for inclusion. After informed consent, patient's demographic and clinical data was abstracted. The current pediatric disease activity index (PCDAI) and endoscopic findings were included. Patients underwent MRE and WCE including preprocedural patency capsule within a maximum of 7 d of each other. Pathological presence of active small bowel disease in ileal and duodenal biopsies were collected if the endoscopy was performed within 2 mo of the WCE study. Patients who failed to pass the PC were excluded from the study. WCE was read by two different experienced gastroenterologists (Attard TM and Colombo JM) blinded to each other's findings and to the findings on MRE (Mardis NJ). Agreement between WCE reviewers, WCE and MRE findings and concordance between positive PCDAI and SBI based on MRE compared with WCE was computed. RESULTS: Forty-five patients were included in the study, 18 withdrew and 27 (20 males and 20 CD), mean age (standard deviation) 13.46 (2.4) years, completed the study protocol. There were no instances of capsule retention. Concordance between gastroenterologist reviewers was excellent for the diagnosis of small intestinal CD with good correlation between the two Lewis scores (r = 0.875, P < 0.001). Concordance between WCE and MRE was poor (69%). In CD patients, when both MRE and WCE were compared using PCDAI > 10 as the standard reference reflecting active small intestinal CD, the sensitivity of MRE and WCE were 100% and 83% respectively and the specificity of MRE and WCE were 57.14% and 78.6%, respectively. If the histology in ileum or/and duodenum was used as the reference for active small bowel involvement, WCE had a higher specificity as compared to MRE (83.3% vs 50%). In patients with Crohn's disease, those with a positive PCDAI (> 10) were more likely to have a positive WCE as compared to those with a negative PCDAI (83% vs 21%; P = 0.018). CONCLUSION: We suggest that MRE and WCE have a complementary role in the assessment of SBI in CD. WCE detected SBI with a much higher specificity while MRE had a higher sensitivity.

Intra-Cochlear Electrocochleography During Cochear Implant Electrode Insertion Is Predictive of Final Scalar Location.

HYPOTHESIS: Electrocochleography (ECochG) patterns observed during cochlear implant (CI) electrode insertion may provide information about scalar location of the electrode array. BACKGROUND: Conventional CI surgery is performed without actively monitoring auditory function and potential damage to intracochlear structures. The central hypothesis of this study was that ECochG obtained directly through the CI may be used to estimate intracochlear electrode position and, ultimately, residual hearing preservation. METHODS: Intracochlear ECochG was performed on 32 patients across 3 different implant centers. During electrode insertion, a 50-ms tone burst stimulus (500 Hz) was delivered at 110 dB SPL. The ECochG response was monitored from the apical-most electrode. The amplitude and phase changes of the first harmonic were imported into an algorithm in an attempt to predict the intracochlear electrode location (scala tympani [ST], translocation from ST to scala vestibuli [SV], or interaction with basilar membrane). Anatomic electrode position was verified using postoperative computed tomography (CT) with image processing. RESULTS: CT analysis confirmed 25 electrodes with ST position and 7 electrode arrays translocating from ST into SV. The ECochG algorithm correctly estimated electrode position in 26 (82%) of 32 subjects while 6 (18%) electrodes were wrongly identified as translocated (sensitivity = 100%, specificity = 77%, positive predictive value = 54%, and a negative predictive value = 100%). Greater hearing loss was observed postoperatively in participants with translocated electrode arrays (36 ±â€Š15 dB) when compared with isolated ST insertions (28 ±â€Š20 dB HL). This result, however, was not significant (p = 0.789). CONCLUSION: Intracochlear ECochG may provide information about CI electrode location and hearing preservation.

Eliciting Higher Maximal and Submaximal Cardiorespiratory Responses During a New Taekwondo-Specific Aerobic Test.

PURPOSE: To propose and validate new taekwondo-specific cardiopulmonary exercise tests. METHODS: Twelve male national-level taekwondo athletes (age 20 [2] y, body mass 67.5 [5.7] kg, height 175 [8] cm, and training experience 7 [3] y) performed 3 separate exercise tests in a randomized counterbalanced order: (1) a treadmill running cardiopulmonary exercise test (CPET) and (2) continuous and (3) interval taekwondo-specific cardiopulmonary exercise tests (cTKDet and iTKDet, respectively). The CPET was administered using an individualized ramp protocol. Taekwondo tests comprised sequences of turning kicks performed on a stationary target. The impacts were recorded via an electronic scoring sensor used in official competition. Stages on the cTKDet and iTKDet lasted 1 min and progressively reduced the kick interval duration. These were guided by a sound signal, starting with 4.6 s between kicks and reducing by 0.4 s every minute until the test ended. Oxygen uptake (V˙O2), heart rate (HR), capillary blood lactate, and ratings of perceived exertion were measured. RESULTS: Modest differences were identified in V˙O2max between the tests (F2,22 = 3.54; P = .046; effect size [ES] = 0.16). Maximal HR (HRmax) was higher during both taekwondo tests (F2,22 = 14.3; P = .001; ES = 1.14) compared with CPET. Specific tests also yielded higher responses in the first ventilatory threshold V˙O2 (F2,22 = 6.5; P = .04; ES = 0.27) and HR (F2,22 = 12.3; P < .001; ES = 1.06), and HR at the second ventilatory threshold (F2,22 = 5.7; P = .02; ES = 0.72). CONCLUSIONS: Taekwondo-specific cardiopulmonary tests enhance the validity of some cardiopulmonary responses and might therefore be considered to optimize routine diagnostic testing and training prescription for this athletic group.

Correction: Physiological responses and external validity of a new setting for taekwondo combat simulation.

[This corrects the article DOI: 10.1371/journal.pone.0171553.].

Variability in the initiation of resuscitation attempts by emergency medical services personnel during out-of-hospital cardiac arrest.

BACKGROUND: Some patients with out-of-hospital cardiac arrest (OHCA) assessed by emergency medical services (EMS) do not receive attempts at resuscitation on the basis of perceived futility. AIMS: 1) To measure variability in the initiation of resuscitation attempts in EMS-assessed OHCA patients across EMS agencies, 2) to evaluate the association between selected EMS agency characteristics and the proportion of patients receiving resuscitation attempts, and 3) to evaluate the association between proportion receiving resuscitation attempts and survival. METHODS: A retrospective cohort study using data from 129 EMS agencies participating in the Resuscitation Outcomes Consortium (ROC) epidemiologic registry (EPISTRY) - Cardiac Arrest from 12/01/2005 to 12/31/2010. We included non-traumatic OHCA patients assessed by EMS. RESULTS: We included 86,912 OHCA patients. Overall, 54.8% had resuscitation attempted by EMS providers, varying from 23.9% to 100% (p=<0.001) across EMS agencies. The proportion of patients receiving a resuscitation attempt was 7.87% less (95% CI 3.73-12.0) among agencies with longer average response intervals (≥6min) compared with shorter average response intervals (<6min) and 16.9% less (95% CI 11.9-21.9) among agencies with higher levels of advanced life support (ALS) availability (≥50% of available units) compared with lower levels of ALS availability (<50% of available units). There was a moderate positive correlation between the proportion of patients with resuscitation attempts and survival to hospital discharge (r=0.54, p<0.001). CONCLUSIONS: The proportion of patients with OHCA who receive resuscitation attempts is variable across EMS agencies and is associated with EMS response interval, ALS unit availability and geographic region. On average, survival was higher among EMS agencies more likely to initiate resuscitation.

Physiological responses and external validity of a new setting for taekwondo combat simulation.

Combat simulations have served as an alternative framework to study the cardiorespiratory demands of the activity in combat sports, but this setting imposes rule-restrictions that may compromise the competitiveness of the bouts. The aim of this study was to assess the cardiorespiratory responses to a full-contact taekwondo combat simulation using a safe and externally valid competitive setting. Twelve male national level taekwondo athletes visited the laboratory on two separate occasions. On the first visit, anthropometric and running cardiopulmonary exercise assessments were performed. In the following two to seven days, participants performed a full-contact combat simulation, using a specifically designed gas analyser protector. Oxygen uptake ([Formula: see text]), heart rate (HR) and capillary blood lactate measurements ([La-]) were obtained. Time-motion analysis was performed to compare activity profile. The simulation yielded broadly comparable activity profiles to those performed in competition, a mean [Formula: see text] of 36.6 ± 3.9 ml.kg-1.min-1 (73 ± 6% [Formula: see text]) and mean HR of 177 ± 10 beats.min-1 (93 ± 5% HRPEAK). A peak [Formula: see text] of 44.8 ± 5.0 ml.kg-1.min-1 (89 ± 5% [Formula: see text]), a peak heart rate of 190 ± 13 beats.min-1 (98 ± 3% HRmax) and peak [La-] of 12.3 ± 2.9 mmol.L-1 was elicited by the bouts. Regarding time-motion analysis, combat simulation presented a similar exchange time, a shorter preparation time and a longer exchange-preparation ratio. Taekwondo combats capturing the full-contact competitive elements of a bout elicit moderate to high cardiorespiratory demands on the competitors. These data are valuable to assist preparatory strategies within the sport.