845 research outputs found

    The Physical Demands of NCAA Division I Women\u27s College Soccer

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    Extensive research into women\u27s collegiate soccer is scarce, leaving gaps in the literature with little information available detailing the physical demands at different standards of play. Our purpose was to elucidate the physical demands of the Division I collegiate level and identify differences between playing positions. Twenty-three field players were observed during four competitive seasons using 10-Hz GPS units (Catapult Sports, Melbourne, Australia). Descriptive statistics and 95% confidence intervals were used to determine group and position-specific physical demands. Linear mixed modelling (LMM) was used to compare attacker, midfielder, and defender position groups. Total distance, high-speed distance, and sprint distance were 9486 ± 300 m, 1014 ± 118 m, and 428 ± 70 m, respectively. Furthermore, attackers were observed to cover the greatest distance at all speeds compared to midfielders and defenders. Our findings suggest that the physical demands of Division I women\u27s soccer differ by position and appear lower compared to higher standards of play. Therefore, coaches and sports scientists responsible for the physical training of Division I collegiate players should consider the specific physical demands of the collegiate level and playing position when prescribing training, as well as in the development of their annual training programs

    Cluster Set Loading in the Back Squat: Kinetic and Kinematic Implications

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    Cluster set loading in the back squat: Kinetic and kinematic implications. J Strength Cond Res XX(X): 000–000, 2018—As athletes become well trained, they require greater stimuli and variation to force adaptation. One means of adding additional variation is the use of cluster loading. Cluster loading involves introducing interrepetition rest during a set, which in theory may allow athletes to train at higher absolute intensities for the same volume. The purpose of this study was to investigate the kinetic and kinematic implications of cluster loading as a resistance training programming tactic compared with traditional loading (TL). Eleven resistance-trained men (age = 26.75 ± 3.98 years, height = 181.36 ± 5.96 cm, body mass = 89.83 ± 10.66 kg, and relative squat strength = 1.84 ± 0.34) were recruited for this study. Each subject completed 2 testing sessions consisting of 3 sets of 5 back squats at 80% of their 1 repetition maximum with 3 minutes of interset rest. Cluster loading included 30 seconds of interrepetition rest with 3 minutes of interset rest. All testing was performed on dual-force plates sampling at 1,000 Hz, and the barbell was connected to 4 linear position transducers sampling at 1,000 Hz. Both conditions had similar values for peak force, concentric average force, and eccentric average force (p = 0.25, effect size (ES) = 0.09, p = 0.25, ES = 0.09, and p = 0.60, ES = 0.04, respectively). Cluster loading had significantly higher peak power (PP) (p \u3c 0.001, ES = 0.77), peak and average velocities (p \u3c 0.001, ES = 0.77, and p \u3c 0.001, ES = 0.81, respectively), lower times to PP and velocity (p \u3c 0.001, ES = −0.68, and p \u3c 0.001, ES = −0.68, respectively) as well as greater maintenance of time to PP (p \u3c 0.001, ES = 1.57). These results suggest that cluster loading may be superior to TL when maintaining power output and time point variables is the desired outcome of training

    The Stability Balloon for Two-dimensional Vortex Ripple Patterns

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    Patterns of vortex ripples form when a sand bed is subjected to an oscillatory fluid flow. Here we describe experiments on the response of regular vortex ripple patterns to sudden changes of the driving amplitude a or frequency f. A sufficient decrease of f leads to a "freezing" of the pattern, while a sufficient increase of f leads to a supercritical secondary "pearling" instability. Sufficient changes in the amplitude a lead to subcritical secondary "doubling" and "bulging" instabilities. Our findings are summarized in a "stability balloon" for vortex ripple pattern formation.Comment: 4 pages, 5 figure

    Chronicles of Oklahoma

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    Notes and Documents, Chronicles of Oklahoma, Volume 33, Number 1, Spring 1955. It includes a letter about an overland journey from Jefferson City to Fort Gibson in 1858, a document about the memory for Mary Greenleaf, a poem by John Walter Sams about "The Ghost of Wapanucka," and a resolution in memory of Oklahoma poet Lynn Riggs

    The ESA-NASA CHOICE Study: Winterover at Concordia Station, Interior Antarctica, A Potential Analog for Spaceflight-Associated Immune Dysregulation

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    For ground-based space physiological research, the choice of terrestrial analog must carefully match the system of interest. Antarctica winter-over at the European Concordia Station is potentially a superior ground-analog for spaceflight-associated immune dysregulation (SAID). Concordia missions consist of prolonged durations in an extreme/dangerous environment, station-based habitation, isolation, disrupted circadian rhythms and international crews. The ESA-NASA CHOICE study assesses innate and adaptive immunity, viral reactivation and stress factors during Concordia winterover deployment. Initial data obtained from the first study deployment (2009 mission; 'n' of 6) will be presented, and logistical challenges regarding analog usage for biological studies will also be discussed. The total WBC increased, and alterations in some peripheral leukocyte populations were observed during winterover at Concordia Station. Percentages of lymphocytes and monocytes increased, and levels of senescent CD8+ T cells were increased during deployment. Transient increases in constitutively activated T cell subsets were observed, at mission time points associated with endemic disease outbreaks. T cell function (early blastogenesis response) was increased near the entry/exit deployment phases, and production of most measured cytokines increased during deployment. Salivary cortisol demonstrated high variability during winterover, but was generally increased. A 2-point circadian rhythm of cortisol measurement (morning/evening) was unaltered during winterover. Perceived stress was mildly elevated during winterover. Other measures, including in-vitro DTH assessment, viral specific T cell number/function and latent herpesvirus reactivation have not yet been completed for the 2009 winterover subjects. Based on the preliminary data, alterations in immune cell distribution and function appear to persist during Antarctic winterover at Concordia Station. Some of these changes are similar to those observed in Astronauts, either during or immediately following spaceflight. Based on the initial immune data and environmental conditions, Concordia winterover may be an appropriate analog for some flight-associated immune changes

    Immune System Dysregulation and Herpesvirus Reactivation Persist During Long-Duration Spaceflight

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    Background: Immunity, latent herpesvirus reactivation, physiological stress and circadian rhythms were assessed during six month spaceflight onboard ISS. Blood and saliva samples were collected early, mid and late in-flight and returned for immediate analysis. Mid-point study data (10 of 17 planned subjects) will be presented. Results: Some shifts in leukocyte distribution occurred during flight, including alterations in CD8+ T cell maturation. General T cell function was consistently reduced early in-flight. Levels CD8+/IFNg+ producing T cells were depressed early in-flight, and immediately upon landing. Persistent mitogen-dependant reductions were observed in IFNg, IL-17a, IL-10, TNFa and IL-6 production. Monocyte production of IL-10 was reduced, whereas IL-8 levels were increased. Levels of mRNA for the TNFa, IL-6 and IFNg were transiently elevated early in-flight, and the dynamics of TNF and IL-6 gene expression were somewhat antagonistic to their corresponding receptors during flight. The number of virus-specific CD8+ T-cells was measured using MHC tetramers, while their function was measured using intracellular cytokine analysis following peptide stimulation. Both the number and function of EBV-specific cells decreased during flight as compared to preflight levels. The number of CMV-specific T-cells generally increased as the mission progressed while their function was variable. Viral (EBV) load in blood was elevated postflight. Anti-EBV VCA antibodies were significantly elevated by R+0; anti-EA antibodies were not significantly elevated at landing; and anti-CMV antibodies were somewhat elevated during flight. Higher levels of salivary EBV DNA were found during flight. VZV DNA reactivation occurred in ~50 % of astronauts during flight, continuing for up to 30 days post-flight. CMV was shed in 35 % the in-flight and 30% of postflight urine samples of the crewmembers. There was generally a higher level of cortisol as measured in urine and saliva in the astronauts during flight, but plasma cortisol was relatively unchanged during flight. Circadian rhythm of salivary cortisol was altered during flight. Conclusion. Some alterations in immunity do not resolve during six month spaceflight, consequentially resulting in persistent herpesvirus reactivation. Ongoing immune dysregulation may represent specific clinical risks for exploration-class space missions

    Inter-Subject Synchronization of Prefrontal Cortex Hemodynamic Activity During Natural Viewing

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    Hemodynamic activity in occipital, temporal, and parietal cortical areas were recently shown to correlate across subjects during viewing of a 30-minute movie clip. However, most of the frontal cortex lacked between-subject correlations. Here we presented 12 healthy naïve volunteers with the first 72 minutes of a movie (“Crash”, 2005, Lions Gate Films) outside of the fMRI scanner to involve the subjects in the plot of the movie, followed by presentation of the last 36 minutes during fMRI scanning. We observed significant between-subjects correlation of fMRI activity in especially right hemisphere frontal cortical areas, in addition to the correlation of activity in temporal, occipital, and parietal areas. It is possible that this resulted from the subjects following the plot of the movie and being emotionally engaged in the movie during fMRI scanning. We further show that probabilistic independent component analysis (ICA) reveals meaningful activations in individual subjects during natural viewing

    NASA 14 Day Undersea Missions: A Short-Duration Spaceflight Analog for Immune System Dysregulation

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    BACKGROUND Spaceflight-associated immune dysregulation (SAID) occurs during spaceflight and may represent specific clinical risks for exploration-class missions. An appropriate ground analog for spaceflight-associated immune dysregulation would offer a platform for ground-evaluation of various potential countermeasures. This study evaluated the NASA Undersea Mission Operations ( NEEMO ), consisting of 14 day undersea deployment at the Aquarius station, as an analog for SAID. Sixteen Aquanauts from missions NEEMO-12, 13 and 14 participated in the study. RESULTS Mid-mission alterations leukocyte distribution occurred, including granulocytosis and elevations in central-memory CD8+ T-cells. General T cell function was reduced during NEEMO missions in roughly 50% of subjects. Secreted cytokines profiles were evaluated following whole blood stimulation with CD3/CD28 (T cells) or LPS (monocytes). T cell production of IFNg, IL-5, IL-10, IL-2, TNFa and IL-6 were all reduced before and during the mission. Conversely, monocyte production of TNFa, IL-10, IL-6, IL-1b and IL-8 were elevated during mission, moreso at the MD-14 timepoint. Antibodies to Epstein-Barr virus (EBV) viral capsid antigen and early antigen were increased in approximately 40% of the subjects. Changes in EBV tetramer-positive CD8+ T-cells exhibited a variable pattern. Antibodies against Cytomegalovirus (CMV) were marginally increased during the mission. Herpesvirus reactivation was determined by PCR. EBV viral load was generally elevated at L-6. Higher levels of salivary EBV were found during the NEEMO mission than before and after as well as than the healthy controls. No VZV or CMV was found in any pre, during and after NEEMO mission or control samples. Plasma cortisol was elevated at L-6. CONCLUSION Unfortunately, L-6 may be too near to mission start to be an appropriate baseline measurement. The general immune changes in leukocyte distribution, T cell function, cytokine production, virus specific immunity and viral reactivation are similar to those observed during or following spaceflight. The NEEMO platform may thus have utility for short-duration, ground-based spaceflight-immune research, such as investigations of mechanism or countermeasures validation

    Establishing a Duration Standard for the Calculation of Session Rating of Perceived Exertion in Ncaa Division I Men’s Soccer

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    Objectives: The purpose of this study was to determine the best predictor of training and/or match load using session RPE. Design and Methods: 20 NCAA DI male soccer players participated in the study during the 2014 and 2015 competitive seasons. Players completed 15.20 ± 1.05 matches for a total of 304 individual data points and 29.90 ± 1.89. training sessions for a total of 598 individual data points. GPS variables (total distance, High-intensity running distance, and Player load) were analyzed with session RPE using Pearson product-moment correlations. To evaluate various methods of session RPE, “match duration” was recorded using eight different definitions: total match duration including warm-up and half-time, total match duration and warm-up, total match duration and half-time, total match duration only, minutes played including warm-up and half-time, minutes played and warm-up, minutes played and half-time, and minutes played only. A one-way ANOVA with repeated measures was used to determine if differences existed between the eight session RPE calculations. Results: Results from the ANOVA showed that all session RPE measures were significantly different from one another (P \u3c 0.05). Very large correlations were reported between session RPE calculated using minutes played and total distance (0.81), while session RPE calculated using match duration showed less magnitude (0.57). Conclusions: Minutes played should be used to calculate session RPE as it was found to most closely reflect the actual workloads incurred during competitive matches
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