203 research outputs found

    Lower Limb Graduated Compression Garments Modulate Autonomic Nervous System and Improve Post-Training Recovery Measured via Heart Rate Variability

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    International Journal of Exercise Science 13(7): 1794-1806, 2020. Prior studies have examined the benefits of graduated compression garments (GCG) with regards to diverse exercise regimens; however, the relationship between GCG and the autonomic nervous system (ANS) has not been fully explored. The aim of this study was to examine Heart Rate Variability (HRV) trends—a proxy for ANS modulation—in response to donning GCG during a progressive overload training regimen designed to induce overtraining. Ten college-aged male novice runners were recruited for the 8-week crossover study. After three weeks of monitored free living, participants were randomized and blinded to an intervention group that donned a lower-body GCG during a two-week exercise regimen or a control group that donned a visually identical but non-compressive sham during identical training. No significant difference in HRV was calculated by the natural logarithm of the root mean square of successive RR-interval differences (lnRMSSD) between the 3-week free-living baseline and GCG intervention periods (P = 0.3040). The mean lnRMSSD was greater during the free-living phase and GCG intervention compared to the sham placebo (P \u3c 0.001 and \u3c0.001 respectively). With regard to the daily fluctuation of lnRMSSD, no significant differences were found between free-living and intervention (P = 1.000). Conversely, the intervention period demonstrated reduced daily fluctuation of lnRMSSD relative to the Sham placebo group (P = 0.010). These novel findings posit that post training use of a commercially available graduated compression garment in novice runners may be effective in counteracting some deleterious effects from overtraining while attenuating its effects on vagally-mediated HRV

    Energy Expenditure and Muscular Recruitment Patterns of Riding a Novel Electrically Powered Skateboard

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    International Journal of Exercise Science 13(4): 1783-1793, 2020. Analysis of metabolic gas exchange and muscular output measures have enabled researchers to index activity intensity and energy expenditure for a myriad of exercises. However, there is no current research that investigates the physiological demands of riding electrically powered skateboards. The aim of this study was to measure the energetic cost and muscular trends of riding a novel electrically powered skateboard engineered to emulate snowboarding on dry-land. While riding the skateboard, eight participants (aged 21-37 years, 1 female) donned a portable breath-by-breath gas analyzer to measure energy expenditure (mean = 12.5, SD = 2 kcal/min), maximum heart rate (mean = 158, SD = 27 bpm), and metabolic equivalent (mean = 10.5, SD = 2 kcal/kg/h). By comparison, snowboarding has a metabolic equivalent (MET) of 8.0. Per the Compendium of Physical Activities guidelines, the predicted MET values for riding an electrically powered skateboard qualifies as vigorous-intensity activity. Four participants additionally wore a surface EMG embedded garment to record the percentage of maximum voluntary contraction (%MVC) of lower limb muscle groups. The inner quadriceps had the most pronounced mean peak muscle activation of 145%MVC during frontside and 164%MVC during frontside turns. EMG recordings showed 11.7%MVC higher utilization during backside turns compared to frontside turns while riding the electrically powered skateboard, which is similar to trends observed in alpine snowboarders. Therefore, electrically powered skateboards may be a promising technology for snowboarders and non-snowboarders alike to burn calories and increase physical activity year-round

    Not All HIFT Classes Are Created Equal: Evaluating Energy Expenditure and Relative Intensity of a High-Intensity Functional Training Regimen

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    International Journal of Exercise Science 13(4): 1206-1216, 2020. The demand for efficient and effective exercises has grown in concert with increased attention to fitness as a determinant of overall health. While past studies have examined the benefits traditional conditioning exercises, there have been few investigations of high intensity functional training (HIFT). The aim of this study was to measure the energy expenditure and relative intensity from participation in a signature, 35-minute group-based HIFT regimen. During the HIFT session, 13 volunteers (aged 23-59 years, 6 females) donned a portable breath-by-breath gas analyzer and a heart rate monitor. Mean caloric expenditure (528 ± 62 kcal), maximum heart rate (172 ± 8 bpm), and metabolic equivalents (12.2 ± 1.4 kcal/kg/h) were characterized as a vigorous-intensity activity according to the Compendium of Physical Activities guidelines. Moreover, implementing this high energy expenditure session twice weekly may comport with Physical Activity Guidelines for Americans weekly physical activity recommendations. HIFT training may provide time-efficient exercise for those seeking exercise-related health benefits

    Muscle Activity and User-Perceived Exertion During Immersive Virtual Reality Exergaming Incorporating an Adaptive Cable Resistance System

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    International Journal of Exercise Science 15(7): 261-275, 2022. The purpose of this exploratory study was to characterize muscle activation via surface electromyography (sEMG), user-perceived exertion, and enjoyment during a 30-minute session of immersive virtual reality (IVR) cable resistance exergaming. Ten healthy, college-aged males completed a signature 30-minute exergaming session using an IVR adaptive cable resistance system that incorporated six traditional compound exercises. Muscle activation (sEMG) was captured during the session with a wearable sEMG system. Rated of Perceived Exertion (RPE) and Physical Activity Enjoyment Scale (PACES) were recorded following the session. Pectoralis major showed the highest activation during chest press, deltoids showed the highest activation on overhead press, latissimus dorsi showed the highest activation during lat pulldown and row exercises, hamstrings were the most activated muscles during Romanian deadlift, and glutes showed the highest activity during squats. RPE and PACES mean scores were 14 (1) and 4.27 (0.38), respectively. IVR exergaming with resistance cable training provides an enjoyable experience and distracts practitioners from exertion while exercising at a high intensity. Results from this study suggest similar muscle activation responses compared to traditional resistance exercises as demonstrated with prior evidence. This novel form of exercise might have important repercussions for improving health outcomes among those who find it challenging to adhere to and enjoy exercise routines, as well as with little knowledge on how to progress in their resistance training. Further investigations are needed to explore long-term adaptations and to assess if IVR exergaming has additional benefits compared to traditional resistance training

    Improved Cosmological Constraints from Gravitational Lens Statistics

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    We combine the Cosmic Lens All-Sky Survey (CLASS) with new Sloan Digital Sky Survey (SDSS) data on the local velocity dispersion distribution function of E/S0 galaxies, ϕ(σ)\phi(\sigma), to derive lens statistics constraints on ΩΛ\Omega_\Lambda and Ωm\Omega_m. Previous studies of this kind relied on a combination of the E/S0 galaxy luminosity function and the Faber-Jackson relation to characterize the lens galaxy population. However, ignoring dispersion in the Faber-Jackson relation leads to a biased estimate of ϕ(σ)\phi(\sigma) and therefore biased and overconfident constraints on the cosmological parameters. The measured velocity dispersion function from a large sample of E/S0 galaxies provides a more reliable method for probing cosmology with strong lens statistics. Our new constraints are in good agreement with recent results from the redshift-magnitude relation of Type Ia supernovae. Adopting the traditional assumption that the E/S0 velocity function is constant in comoving units, we find a maximum likelihood estimate of ΩΛ=0.74\Omega_\Lambda = 0.74--0.78 for a spatially flat unvierse (where the range reflects uncertainty in the number of E/S0 lenses in the CLASS sample), and a 95% confidence upper bound of ΩΛ<0.86\Omega_\Lambda<0.86. If ϕ(σ)\phi(\sigma) instead evolves in accord with extended Press-Schechter theory, then the maximum likelihood estimate for ΩΛ\Omega_\Lambda becomes 0.72--0.78, with the 95% confidence upper bound ΩΛ<0.89\Omega_\Lambda<0.89. Even without assuming flatness, lensing provides independent confirmation of the evidence from Type Ia supernovae for a nonzero dark energy component in the universe.Comment: 35 pages, 15 figures, to be published in Ap

    Optical one-way quantum computing with a simulated valence-bond solid

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    One-way quantum computation proceeds by sequentially measuring individual spins (qubits) in an entangled many-spin resource state. It remains a challenge, however, to efficiently produce such resource states. Is it possible to reduce the task of generating these states to simply cooling a quantum many-body system to its ground state? Cluster states, the canonical resource for one-way quantum computing, do not naturally occur as ground states of physical systems. This led to a significant effort to identify alternative resource states that appear as ground states in spin lattices. An appealing candidate is a valence-bond-solid state described by Affleck, Kennedy, Lieb, and Tasaki (AKLT). It is the unique, gapped ground state for a two-body Hamiltonian on a spin-1 chain, and can be used as a resource for one-way quantum computing. Here, we experimentally generate a photonic AKLT state and use it to implement single-qubit quantum logic gates.Comment: 11 pages, 4 figures, 8 tables - added one referenc

    The NICE-GUT trial protocol:A randomised, placebo controlled trial of oral nitazoxanide for the empiric treatment of acute gastroenteritis among Australian Aboriginal children

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    Diarrhoeal disease is the second leading cause of death in children under 5 years globally, killing 525 000 annually. Australian Aboriginal and Torres Strait Islander (hereafter Aboriginal) children suffer a high burden of disease. Randomised trials in other populations suggest nitazoxanide accelerates recovery for children with Giardia, amoebiasis, Cryptosporidium, Rotavirus and Norovirus gastroenteritis, as well as in cases where no enteropathogens are found. This double blind, 1:1 randomised, placebo controlled trial is investigating the impact of oral nitazoxanide on acute gastroenteritis in hospitalised Australian Aboriginal children aged 3 months to <5 years. Dosing is based on age-based dosing. The primary endpoint is the time to resolution of 'significant illness' defined as the time from randomisation to the time of clinical assessment as medically ready for discharge, or to the time of actual discharge from hospital, whichever occurs first. Secondary endpoints include duration of hospitalisation, symptom severity during the period of significant illness and following treatment, duration of rehydration and drug safety. Patients will be followed for medically significant events for 60 days. Analysis is based on Bayesian inference. Subgroup analysis will occur by pathogen type (bacteria, virus or parasite), rotavirus vaccination status, age and illness severity. Ethics approval has been granted by the Central Australian Human Research Ethics Committee (HREC-14-221) and the Human Research Ethics Committee of the Northern Territory Department of Health and Menzies School of Health Research (HREC2014-2172). Study investigators will ensure that the trial is conducted in accordance with the principles of the Declaration of Helsinki. Individual participant consent will be obtained. Results will be disseminated via peer-reviewed publication. ACTRN12614000381684

    Emergent dynamic chirality in a thermally driven artificial spin ratchet

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    Modern nanofabrication techniques have opened the possibility to create novel functional materials, whose properties transcend those of their constituent elements. In particular, tuning the magnetostatic interactions in geometrically frustrated arrangements of nanoelements called artificial spin ice1, 2 can lead to specific collective behaviour3, including emergent magnetic monopoles4, 5, charge screening6, 7 and transport8, 9, as well as magnonic response10, 11, 12. Here, we demonstrate a spin-ice-based active material in which energy is converted into unidirectional dynamics. Using X-ray photoemission electron microscopy we show that the collective rotation of the average magnetization proceeds in a unique sense during thermal relaxation. Our simulations demonstrate that this emergent chiral behaviour is driven by the topology of the magnetostatic field at the edges of the nanomagnet array, resulting in an asymmetric energy landscape. In addition, a bias field can be used to modify the sense of rotation of the average magnetization. This opens the possibility of implementing a magnetic Brownian ratchet13, 14, which may find applications in novel nanoscale devices, such as magnetic nanomotors, actuators, sensors or memory cells
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