1,714 research outputs found

    Carbohydrate and caffeine improves high intensity running of elite rugby league interchange players during simulated match play.

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    The study examined the effects of carbohydrate and caffeine ingestion on simulated rugby league interchange performance. Eight male elite rugby league forwards completed two trials of a rugby league simulation protocol for interchange players seven days apart in a randomized crossover design, ingesting either carbohydrate (CHO; 40 g·h-1) or carbohydrate and caffeine (CHO-C) (40 g·h-1 + 3 mg·kg-1) drink. Movement characteristics, heart rate, ratings of perceived exertion (RPE), and countermovement jump height (CMJ) were measured during the protocol. CHO-C resulted in likely to very likely higher mean running speeds (ES 0.43 to 0.75), distance in high intensity running (ES 0.41 to 0.64) and mean sprint speeds (ES 0.39 to 1.04) compared to CHO. Heart rate was possibly to very likely higher (ES 0.32 to 0.74) and RPE was likely to very likely lower (ES -0.53 to 0.86) with CHO-C. There was a likely trivial to possibly higher CMJ in CHO-C compared to CHO (ES 0.07 to 0.25). The co-ingestion of carbohydrate with caffeine has an ergogenic effect to reduce the sense of effort and increase high intensity running capability that might be employed to enhance interchange running performance in elite rugby league players

    Activation of the <i>gluteus maximus</i> during performance of the back squat, split squat and barbell hip thrust and the relationship with maximal sprinting

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    The purpose of this research was to compare muscle activation of the gluteus maximus and ground reaction force between the barbell hip thrust, back squat, and split squat and to determine the relationship between these outcomes and vertical and horizontal forces during maximal sprinting. Twelve male team sport athletes (age 25.0 ± 4.0 years, stature 184.1 ± 6.0 cm, body mass 82.2 ± 7.9 kg) performed separate movements of the three strength exercises at a load equivalent to their individual three repetition maximum. The ground reaction force was measured using force plates and the electromyography (EMG) activity of the upper and lower gluteus maximus was recorded in each leg and expressed as percentage of the maximum voluntary isometric contraction (MVIC). Participants then completed a single sprint on a non-motorized treadmill for the assessment of maximal velocity, horizontal and vertical forces. Although ground reaction force was lower, peak EMG activity in the gluteus maximus was higher in the hip thrust than the back squat (p = 0.024; 95%CI = 4 – 56%MVIC) and split squat (p = 0.016; 95%CI = 6 – 58%MVIC). Peak sprint velocity was correlated with both anterior-posterior horizontal force (r = 0.72) and peak ground reaction force during the barbell hip thrust (r = 0.69) but no other variables. The increased activation of gluteus maximus during the barbell hip thrust and the relationship with maximal running speed suggests that this movement may be optimal for training this muscle group in comparison to the back squat and split squat

    Chitosan gel vaccine protects against tumour growth in an intracaecal mouse model of cancer by modulating systemic immune responses

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    Background Vaccination generating a robust memory population of CD8+ T cells may provide protection against cancer. However, immune therapies for cancer are influenced by the local tumour immune microenvironment. An infiltrate of T cells into tumours of people with colorectal cancer has proven to be a significant indicator of good prognosis. Methods We used an intracaecal mouse model of cancer to determine whether a protective immune response against a mucosal gut tumour could be generated using a systemic intervention. We investigated the generation of murine memory CD8+ T cells using a sustained antigen release vaccine vehicle (chitosan gel; Gel + OVA) containing the model antigen ovalbumin, chitosan gel alone (Gel) or conventional dendritic cell vaccination (DC + OVA) using the same protein antigen. Results Following vaccination with Gel + OVA, CD8+ T cell memory populations specific for ovalbumin protein were detected. Only vaccination with Gel + OVA gave decreased tumour burden compared to unvaccinated or DC + OVA-vaccinated mice in the intracaecal cancer challenge model. Conclusion These results indicate that subcutaneous vaccination with Gel + OVA generates a population of functional CD8+ memory T cells in lymphoid tissue able to protect against intracaecal tumour challenge. Vaccination with chitosan gel may be valuable in anti-cancer treatment at both peripheral and mucosal sites

    BrainSignals Revisited: Simplifying a Computational Model of Cerebral Physiology

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    Multimodal monitoring of brain state is important both for the investigation of healthy cerebral physiology and to inform clinical decision making in conditions of injury and disease. Near-infrared spectroscopy is an instrument modality that allows non-invasive measurement of several physiological variables of clinical interest, notably haemoglobin oxygenation and the redox state of the metabolic enzyme cytochrome c oxidase. Interpreting such measurements requires the integration of multiple signals from different sources to try to understand the physiological states giving rise to them. We have previously published several computational models to assist with such interpretation. Like many models in the realm of Systems Biology, these are complex and dependent on many parameters that can be difficult or impossible to measure precisely. Taking one such model, BrainSignals, as a starting point, we have developed several variant models in which specific regions of complexity are substituted with much simpler linear approximations. We demonstrate that model behaviour can be maintained whilst achieving a significant reduction in complexity, provided that the linearity assumptions hold. The simplified models have been tested for applicability with simulated data and experimental data from healthy adults undergoing a hypercapnia challenge, but relevance to different physiological and pathophysiological conditions will require specific testing. In conditions where the simplified models are applicable, their greater efficiency has potential to allow their use at the bedside to help interpret clinical data in near real-time
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