The acute effects different quantities of branched-chain amino acids have on recovery of muscle function

Purpose: Branched-chain amino acid (BCAA) supplementation has been shown to significantly reduce the undesirable effects commonly associated with high-intensity training, which include decreases in muscle function and increases in muscle soreness. However, the application of associated BCAA research to the athletic setting is limited, as supplementation protocols have contained either low (3 - 6g), or high (20g) dosages of BCAA, generally administered to untrained individuals. The present study investigated the acute effects of two different quantities of BCAA on the recovery of muscle function following high-intensity resistance training in trained individuals. The main aim was to examine whether there is a dose-response effect of using a higher dosage of BCAA on recovery when compared to a lower dosage. Methods: Five resistance-trained males (mean ± SD, age: 21.8 ± 0.8 years, stature: 1.81 ± 0.57 m, body mass: 83.3 ± 7.2 kg) were recruited and performed baseline assessments including, countermovement (CMJ) and squat jump (SJ), peak (PP) and mean (MP) power (6 s Wingate Cycle) and perceived muscle soreness (soreness). In a counterbalanced, single-blind fashion, participants were provided with either, placebo (blackcurrant squash with negligible calorie content) or 6g or 18g BCAA 20 min prior to, and immediately after completion of a high-intensity strength session (ST). At 24 h post ST, all assessments were completed under all three experimental conditions. Results: Following ST, there were significant decrements in all measures of muscle function across conditions when compared to baseline values (p < 0.05). However, ingestion of 6g and 18g BCAA was shown to significantly attenuate these decrements in comparison to placebo (p < 0.05). A dose-response for BCAA was also present as significant differences (p < 0.05) were shown between ingestion of 6g and 18g; CMJ (18g: 59.1 cm, 6g: 57.7 cm, placebo: 56.6cm), SJ (18g: 54.0 cm, 6g: 52.8 cm, placebo: 51.7 cm), PP (18g: 1133 W, 6g: 1107 W, placebo: 1044 W), MP (18g: 1011 W, 6g: 986 W, placebo: 972 W), soreness (18g: 81 mm, 6g: 91 mm, placebo: 100 mm). Conclusions: BCAA ingested both acutely before, and immediately following intensive resistance training attenuates the decrement observed in muscle function, while alleviating symptoms of muscle soreness. These small but significant findings not only support the proposed ergogenic benefits of BCAA supplementation, but also highlight a potential dose-response, with a higher dose (18g) having a significantly greater effect than a lower dose (6g) in trained individuals

An update on effects of creatine supplementation on performance: a review

Supplementary creatine, available in many different forms but most commonly monohydrate, is a legal and reportedly safe to consume nutritional ergogenic aid. After searching internationally recognised research databases, this review provides and update on the current literature on the physiological effects of creatine supplementation on performance whilst also discussing the underlying physiology regarding the synthesis and dietary provision of creatine as well as addressing issues of safety and the ethical considerations of usage. Research has shown that regular consumption of supplementary creatine can raise associated content within skeletal muscle. Subsequently, there is an extensive, and still growing, body of the literature supporting the efficacy of creatine supplementation on enhancing exercise performance, exercise tolerance, muscle strength and lean body mass. Moreover, little scientific evidence exists showing any unfavourable effects on individuals who are free from illness and disease. This review consolidates the current literature and provides application to the athletic setting which is purposeful for those choosing to either recommend or consume this nutritional ergogenic aid. At this current time, a traditional loading and maintenance supplementation protocol is advised as contemporary research studies are still to unravel the benefits of alternative approaches

An explorative investigation into the warm-up practices of both professional and amateur rugby league players

PURPOSE: Rugby League (RL) players require high levels of speed, strength, power, agility and psychological readiness. Optimum preparation for performance via warm-up (WU) routines has been an area of research speculation in recent years. This study aimed to survey the WU protocols of professional and amateur RL players, to determine player’s perceptions of their featured WU procedures and to establish any significant differences in WU practices and perceptions between the two populations. METHODS: An online questionnaire was used to investigate 30 professional and 53 amateur players’ WU protocols and their perceptions behind their practices, providing both statistical and descriptive analysis. For a more in depth understanding into the practices and perceptions of the featured protocols, the questionnaire was followed up by two focus groups which included four participants in each (one professional group and one amateur). Raw data was produced from the focus groups which was then placed within higher-order themes and general dimensions. RESULTS: The questionnaire revealed a significant between-group difference for the duration of the WU’s between the two separate standards (P = 0.009). Professionals’ WU protocols were considerably longer in duration compared to the amateurs’ protocols; 67% of professional players performed WU routines for 15+ min whereas only 42% of amateur players claimed to WU for 15+ min. However, no between-group differences existed for protocols, perception variables, static stretching (SS) duration and similarity of the WU protocol (P > 0.05). The questionnaire also revealed the prevalence of SS; 83% of amateur participants and 90% of professional players claimed to perform SS during their WU. The focus group revealed that RL players’ protocols and perceptions of their regime are due to the influences of others such as coaches, strength and conditioning practitioners and physiotherapists and emphasises the importance the role such professionals play. CONCLUSIONS: The results showed that professional participants WU for a longer period in comparison to amateurs. The high prevalence of SS within RL WU protocols at both a professional and amateur standard was clearly apparent, contradicting the vast amount of literature that would advocate the removal of SS in sports requiring explosive power due to the associated links with decrements in performance. Most professional and amateur RL participants were discovered to perform SS for a duration that has been proven to impair desired physiological attributes. Furthermore, the study revealed the dynamic element of a WU is being consistently placed before SS, by both the professional and amateur domain, which has been previously linked to decreases in body temperature and associated mechanisms related mechanisms. Players associated that there WU practice was heavily influenced by RL coaches and associated practitioners. PRACTICAL APPLICTIONS: It is recommended that coaches, strength and conditioning practitioners and other key influential figures are educated on optimal evidence based WU procedures prior to prescription. Important aspects for consideration and education include WU duration, intensity, protocol order and SS elongation, volume and duration. Whilst it is important to link the research in WU to performance, practitioners should be mindful of changing regimes abruptly and the idiosyncratic nature of how athletes prefer to prepare physically and mentally

Validity and whole system reliability of a commercially available linear positional transducer across common resistance training exercises

PURPOSE: To assess the validity and whole system reliability of the GymAware power tool across a range of traditional strength training exercises. METHODS: Thirteen resistance trained individuals (mean ± SD, age: 26.5 ± 4.8 years, stature: 174.1 ± 9.5 cm, body mass: 81.9 ± 12.1 kg) were recruited. Subjects completed three repeated visits, each consisting of three repetitions of free-weight back squat, bench press, and deadlift (all at 80% one repetition maximum). Lift displacement data were collected using a linear positional transducer (GymAware; Kinetic Performance Technology, Canberra, Australia) and a five-camera 3D motion capture system (Motion Analysis Corporation, Santa Rosa, CA; 150 Hz). Simultaneous force data were collected (Kistler, Switzerland; 1500 Hz) for all lifts excluding bench press. Lift displacement, peak and mean velocity and force were calculated via the GymAware software and custom written MATLAB code (Mathworks, Natick, MA). Least products regression was calculated between measuring devices for quantification of validity across variables and expressed as an R2 value. A one-way repeated measures ANOVA, typical error (TE %) and smallest worthwhile change (SWC) were used to assess the between visit data across all variables. RESULTS: For back squat, comparisons between measuring devices across all variables resulted in an R2 0.99. Similarly, deadlift comparisons across all variables between measuring devices resulted in an R2 0.92, excluding mean velocity (R2 0.69). Correlations between measuring devices across all variables for bench press resulted in R2 0.85. No significant differences were reported for any variables for the back squat. In contrast, significant differences were observed for bench press visits 2-1 and 3-2 (mean ± SD: visit 1: 0.382 ± 0.063 m; visit 2: 0.383 ± 0.053 m; visit 3: 0.395 ± 0.055 m), with no significant differences recorded between other variables. Significant differences were observed between visits 3-2 for deadlift displacement (mean ± SD: visit 2: 0.568 ± 0.034 m; visit 3: 0.557 ± 0.034 m), with no significant differences found between other variables. Mean TE % ranged from low to moderate between back squat (0.6-8.1%), bench press (3.0-7.4%), and deadlift (1.6-8.8%) visits, with SWC ranging from 1.7-7.4%. CONCLUSION: The GymAware provides valid measures of displacement and subsequent derivatives across a range of strength training exercises in resistance trained individuals. Furthermore, low to moderate TE following repeated trials signify high levels of test re-test consistency. The results do suggest care should be taken when monitoring deadlift performance, however further research is required to determine the source of observed error before drawing full conclusions. PRACTICAL APPLICATION: The data presented provides sufficient evidence that the GymAware can be used to measure kinetic and kinematic outputs both accurately and reliably in a resistance trained population. These findings have several applied applications, including providing real-time feedback to athletes, informing decisions regarding programme progression, determining readiness to train, and longitudinal monitoring of athletic performance. In addition, the confirmation of the GymAware to provide valid and reliable measures of movement performance allows practitioners to utilise this tool within innovative testing and training methods which would otherwise require resource- and labour-intensive protocols

Racing Towards Reinforcement Learning based control of an Autonomous Formula SAE Car

With the rising popularity of autonomous navigation research, Formula Student (FS) events are introducing a Driverless Vehicle (DV) category to their event list. This paper presents the initial investigation into utilising Deep Reinforcement Learning (RL) for end-to-end control of an autonomous FS race car for these competitions. We train two state-of-the-art RL algorithms in simulation on tracks analogous to the full-scale design on a Turtlebot2 platform. The results demonstrate that our approach can successfully learn to race in simulation and then transfer to a real-world racetrack on the physical platform. Finally, we provide insights into the limitations of the presented approach and guidance into the future directions for applying RL toward full-scale autonomous FS racing.Comment: Accepted at the Australasian Conference on Robotics and Automation (ACRA 2022

Comparison of velocity-based and traditional percentage-based loading methods on maximal strength and power adaptations

This study explored the effects of velocity-based training (VBT) on maximal strength and jump height. Sixteen trained males (22.8 ± 4.5 years) completed a countermovement jump test (CMJ), and one repetition maximum (1-RM) assessment on back squat, bench press, strict overhead press, and deadlift, before and after six weeks of resistance training. Participants were assigned to VBT, or percentage-based training (PBT) groups. The VBT group’s load was dictated via real-time velocity monitoring, as opposed to pre-testing 1-RM data (PBT). No significant differences were present between groups for pre-testing data (p > 0.05). Training resulted in significant increases (p < 0.05) in maximal strength for back squat (VBT 9%, PBT 8%), bench press (VBT 8%, PBT 4%), strict overhead press (VBT 6%, PBT 6%), and deadlift (VBT 6%). Significant increases in CMJ were witnessed for the VBT group only (5%). A significant interaction effect was witnessed between training groups for bench press (p = 0.004) and CMJ (p = 0.018). Furthermore, for back squat (9%), bench press (6%), and strict overhead press (6%), a significant difference was present between the total volume lifted. The VBT intervention induced favorable adaptations in maximal strength and jump height in trained males when compared to a traditional PBT approach. Interestingly the VBT group achieved these positive outcomes despite a significant reduction in total training volume compared to the PBT group. This has potentially positive implications for the management of fatigue during resistance training

Validity and reliability of a linear positional transducer across commonly practised resistance training exercises

This study investigated the validity and reliability of the GymAware PowerTool (GPT). Thirteen resistance trained participants completed three visits, consisting of three repetitions of free-weight back squat, bench press, deadlift (80% one repetition maximum), and countermovement jump. Bar displacement, peak and mean velocity, peak and mean force, and jump height were calculated using the GPT, a three dimensional motion capture system (Motion Analysis Corporation; 150 Hz), and a force plate (Kistler; 1500 Hz). Least products regression were used to compare agreeability between devices. A within-trial one-way ANOVA, typical error (TE; %), and smallest worthwhile change (SWC) were used to assess reliability. Regression analysis resulted in R2 values of >0.85 for all variables excluding deadlift mean velocity (R2 = 0.54–0.69). Significant differences were observed between visits 3-2 for bench press bar displacement (0.395 ± 0.055 m; 0.383 ± 0.053 m), and deadlift bar displacement (0.557 ± 0.034 m; 0.568 ± 0.034 m). No other significant differences were found. Low to moderate TE (0.6–8.8%) were found for all variables, with SWC ranging 1.7–7.4%. The data provides evidence that the GPT can be used to measure kinetic and kinematic outputs, however, care should be taken when monitoring deadlift performance

Pleckstrin Homology Domain 1 of Mouse R1-Syntrophin Binds Phosphatidylinositol 4,5-Bisphosphate †

ABSTRACT: Mouse R1-syntrophin sequences were produced as chimeric fusion proteins in bacteria and found to bind phosphatidylinositol 4,5-bisphosphate (PtdIns4,5P 2 ). Half-maximal binding occurred at 1.9 µM PtdIns4,5P 2 and when 1.2 PtdIns4,5P 2 were added per syntrophin. Binding was specific for PtdIns4,5P 2 and did not occur with six other tested lipids including the similar phosphatidylinositol 4-phosphate. Binding was localized to the N-terminal pleckstrin homology domain (PH1); the second, C-terminal PH2 domain did not bind lipids. Key residues in PtdIns4,5P 2 binding to a PH domain were found to be conserved in R-syntrophins&apos; PH1 domains and absent in PH2 domains, suggesting a molecular basis for binding

Quantum Interference Enhances the Performance of Single-Molecule Transistors

An unresolved challenge facing electronics at a few-nm scale is that resistive channels start leaking due to quantum tunneling. This affects the performance of nanoscale transistors, with single-molecule devices displaying particularly low switching ratios and operating frequencies, combined with large subthreshold swings.1 The usual strategy to mitigate quantum effects has been to increase device complexity, but theory shows that if quantum effects are exploited correctly, they can simultaneously lower energy consumption and boost device performance.2-6 Here, we demonstrate experimentally how the performance of molecular transistors can be improved when the resistive channel contains two destructively-interfering waves. We use a zinc-porphyrin coupled to graphene electrodes in a three-terminal transistor device to demonstrate a >104 conductance-switching ratio, a subthreshold swing at the thermionic limit, a > 7 kHz operating frequency, and stability over >105 cycles. This performance is competitive with the best nanoelectronic transistors. We fully map the antiresonance interference features in conductance, reproduce the behaviour by density functional theory calculations, and trace back this high performance to the coupling between molecular orbitals and graphene edge states. These results demonstrate how the quantum nature of electron transmission at the nanoscale can enhance, rather than degrade, device performance, and highlight directions for future development of miniaturised electronics.Comment: 11 pages, 4 figure