Effects of post activation potentiation on electromechanical delay

Electromechanical delay (EMD) presumably depends upon both contractile and tensile factors. It has recently been used as an indirect measure of muscle tendon stiffness to study adaptations to stretching and training. The aim of the present study was to investigate whether contractile properties induced by a 6 s maximum voluntary isometric contraction (MVIC) could affect EMD without altering passive muscle tendon stiffness or stiffness index. Plantar flexor twitches were evoked via electrical stimulation of the tibial nerve in eight highly trained male sprinters before and after a 6 s MVIC in passive isometric or passively shortening or lengthening muscles. For each twitch, EMD, twitch contractile properties and SOLM-Wave were measured. Passive muscle tendon stiffness was measured from the slope of the relation between torque and ankle angle during controlled passive dorsal flexion and stiffness index by curve-fitting the torque angle data using a second-order polynomial function. EMD did not differ between isometric, lengthening or shortening movements. EMD was reduced by up to 11.56 ± 5.64% immediately after the MVIC and stayed depressed for up to 60 s after conditioning. Peak twitch torque and rate of torque development were potentiated by up to 119.41 ± 37.15% and 116.06 ± 37.39%, respectively. Rising time was reduced by up to 14.46 ± 7.22%. No significant changes occurred in passive muscle tendon stiffness or stiffness index. Using a conditioning MVIC, it was shown that there was an acute enhancement of contractile muscle properties as well as a significant reduction in EMD with no corresponding changes in stiffness. Therefore, caution should be taken when using and interpreting EMD as a proxy for muscle tendon stiffness.info:eu-repo/semantics/publishedVersio

Detecting prolonged sitting bouts with the ActiGraph GT3X

The ActiGraph has a high ability to measure physical activity; however, it lacks an accurate posture classification to measure sedentary behavior. The aim of the present study was to develop an ActiGraph (waist-worn, 30 Hz) posture classification to detect prolonged sitting bouts, and to compare the classification to proprietary ActiGraph data. The activPAL, a highly valid posture classification device, served as reference criterion. Both sensors were worn by 38 office workers over a median duration of 9 days. An automated feature selection extracted the relevant signal information for a minute-based posture classification. The machine learning algorithm with optimal feature number to predict the time in prolonged sitting bouts (>= 5 and >= 10 minutes) was searched and compared to the activPAL using Bland-Altman statistics. The comparison included optimized and frequently used cut-points (100 and 150 counts per minute (cpm), with and without low-frequency-extension (LFE) filtering). The new algorithm predicted the time in prolonged sitting bouts most accurate (bias <= 7 minutes/d). Of all proprietary ActiGraph methods, only 150 cpm without LFE predicted the time in prolonged sitting bouts non-significantly different from the activPAL (bias <= 18 minutes/d). However, the frequently used 100 cpm with LFE accurately predicted total sitting time (bias <= 7 minutes/d). To study the health effects of ActiGraph measured prolonged sitting, we recommend using the new algorithm. In case a cut-point is used, we recommend 150 cpm without LFE to measure prolonged sitting and 100 cpm with LFE to measure total sitting time. However, both cpm cut-points are not recommended for a detailed bout analysis.NoneAccepte

Physiological Responses and Physical Performance during Football in the Heat

PURPOSE: To examine the impact of hot ambient conditions on physical performance and physiological responses during football match-play. METHODS: Two experimental games were completed in temperate (∼ 21°C; CON) and hot ambient conditions (∼ 43°C; HOT). Physical performance was assessed by match analysis in 17 male elite players during the games and a repeated sprint test was conducted after the two game trials. Core and muscle temperature were measured and blood samples were obtained, before and after the games. RESULTS: Muscle and core temperatures were ∼ 1°C higher (P<0.05) in HOT (40.3 ± 0.1 and 39.5 ± 0.1°C, respectively) compared to CON (39.2 ± 0.1 and 38.3 ± 0.1°C). Average heart rate, plasma lactate concentration, body weight loss as well as post-game sprint performance were similar between the two conditions. Total game distance declined (P<0.05) by 7% and high intensity running (>14 km ⋅ h(-1)) by 26% in HOT compared to CON), but peak sprint speed was 4% higher (P<0.05) in HOT than in CON, while there were no differences in the quantity or length of sprints (>24 km ⋅ h(-1)) between CON and HOT. In HOT, success rates for passes and crosses were 8 and 9% higher (P<0.05), respectively, compared to CON. Delta increase in core temperature and absolute core temperature in HOT were correlated to total game distance in the heat (r = 0.85 and r = 0.53, respectively; P<0.05), whereas, total and high intensity distance deficit between CON and HOT were not correlated to absolute or delta changes in muscle or core temperature. CONCLUSION: Total game distance and especially high intensity running were lower during a football game in the heat, but these changes were not directly related to the absolute or relative changes in core or muscle temperature. However, peak sprinting speed and execution of successful passes and crosses were improved in the HOT condition

The Use of Functional Data Analysis to Evaluate Activity in a Spontaneous Model of Degenerative Joint Disease Associated Pain in Cats

Introduction and objectives: accelerometry is used as an objective measure of physical activity in humans and veterinary species. In cats, one important use of accelerometry is in the study of therapeutics designed to treat degenerative joint disease (DJD) associated pain, where it serves as the most widely applied objective outcome measure. These analyses have commonly used summary measures, calculating the mean activity per-minute over days and comparing between treatment periods. While this technique has been effective, information about the pattern of activity in cats is lost. In this study, functional data analysis was applied to activity data from client-owned cats with (n = 83) and without (n = 15) DJD. Functional data analysis retains information about the pattern of activity over the 24-hour day, providing insight into activity over time. We hypothesized that 1) cats without DJD would have higher activity counts and intensity of activity than cats with DJD; 2) that activity counts and intensity of activity in cats with DJD would be inversely correlated with total radiographic DJD burden and total orthopedic pain score; and 3) that activity counts and intensity would have a different pattern on weekends versus weekdays. Results and conclusions: results showed marked inter-cat variability in activity. Cats exhibited a bimodal pattern of activity with a sharp peak in the morning and broader peak in the evening. Results further showed that this pattern was different on weekends than weekdays, with the morning peak being shifted to the right (later). Cats with DJD showed different patterns of activity from cats without DJD, though activity and intensity were not always lower; instead both the peaks and troughs of activity were less extreme than those of the cats without DJD. Functional data analysis provides insight into the pattern of activity in cats, and an alternative method for analyzing accelerometry data that incorporates fluctuations in activity across the day.UCR::Vicerrectoría de Docencia::Ciencias Sociales::Facultad de Ciencias Económicas::Escuela de Estadístic

Correlation between subjective change after shunt surgery and the iNPH-scale in patients with idiopathic normal pressure hydrocephalus

Normaltryckshydrocefalus (NPH) drabbar den äldre populationen med motoriska och kognitiva nedsättningar. Behandlingen är dränering av likvorvätska via shuntoperation och patientens symptom förväntas då gå i regress. Det saknas dock studier om förändring på iNPH-skalan stämmer överens med patientens subjektiva skattade förändring. Syftet var att studera om patientens subjektiva upplevda förändring stämmer överens med skattningsskalor och hur en förändring av förmågor påverkar livskvalitet. Syftet var även att undersöka vilken betydelse som förändring av förmågor har för patienten och anhöriga. Studien var en mixad observativ tvärsnittsstudie där 52 deltagare (26 patienter och 26 anhöriga) inkluderades och fick svara på en enkät framtaget för studien. Patienterna graderades enligt iNPH-skalan mellan diagnos och 3 månader efter shuntoperation. Resultatet visade att 76,9 % av patienterna förbättrades på iNPH-skalan efter operation. Det förelåg en signifikant korrelation mellan förändring på iNPH-skalan och förändring av gångförmåga (rs=0,42) och förändring av rörelseförmåga (rs=0,49), samt subjektiv skattad förändring mätt med VAS-skala (rs=0,43). Det förelåg ingen signifikant korrelation mellan förändring på iNPH-skalan och förändring av livskvalitet. Gång- och rörelseförmåga skattades som de förmågor som förbättrats mest postoperativt. Förbättring av dessa förmågor samt förbättrad vardagsaktivitet hade störst betydelse för deltagarna. Fler studier behövs för att närmare studera vilka förmågor som kan korrelera med förbättrad livskvalitet

Frequent, Short Physical Activity Breaks Reduce Prefrontal Cortex Activation but Preserve Working Memory in Middle-Aged Adults : ABBaH Study.

Prolonged sitting is increasingly common and may possibly be unfavorable for cognitive function and mood. In this randomized crossover study, the effects of frequent, short physical activity breaks during prolonged sitting on cognitive task-related activation of the prefrontal cortex were investigated. The effects on working memory, psychological factors, and blood glucose were also examined, and whether arterial stiffness moderated prefrontal cortex activation. Thirteen subjects (mean age 50.5 years; eight men) underwent three 3-h sitting conditions, interrupted every 30-min by a different 3-min break on separate, randomized-ordered days: seated social interactions (SOCIAL), walking (WALK), or simple resistance activities (SRA). Arterial stiffness was assessed at baseline. Before and after each 3-h condition, psychological factors (stress, mood, sleepiness, and alertness) were assessed through questionnaires and functional near-infrared spectroscopy (fNIRS) was used to measure changes in prefrontal oxygenated hemoglobin (Oxy-Hb), indicative of cortical activation, while performing working memory tasks [1- (baseline), 2-, and 3-back]. Blood glucose levels were continuously measured throughout the conditions. Results revealed no significant changes in Oxy-Hb during the 2-back compared with the 1-back test in any condition, and no time-by-condition interactions. During the 3-back test, there was a significant decrease in Oxy-Hb compared with the 1-back after the WALK condition in the right prefrontal cortex, but there were no time-by-condition interactions, although 3-back reaction time improved only in the WALK condition. Mood and alertness improved after the WALK condition, which was significantly different from the SOCIAL condition. Arterial stiffness moderated the effects, such that changes in Oxy-Hb were significantly different between WALK and SOCIAL conditions only among those with low arterial stiffness. Blood glucose during the interventions did not differ between conditions. Thus, breaking up prolonged sitting with frequent, short physical activity breaks may reduce right prefrontal cortex activation, with improvements in some aspects of working memory, mood, and alertness. Clinical Trial Registration:www.ClinicalTrials.gov, identifier NCT04137211.Fysisk aktivitet och hälsosamma hjärnfunktioner bland kontorsarbetare. Delprojekt 2 Akuta interventione

Criterion validity of the Ekblom-Bak and the Åstrand submaximal test in an elderly population.

PURPOSE: The aim of this study was to validate the submaximal Ekblom-Bak test (EB-test) and the Åstrand test (Å-test) for an elderly population. METHODS: Participants (n = 104), aged 65-75 years, completed a submaximal aerobic test on a cycle ergometer followed by an individually adjusted indirect calorimetry VO2max test on a treadmill. The HR from the submaximal test was used to estimate VO2max using both the EB-test and Å-test equations. RESULTS: The correlation between measured and estimated VO2max using the EB method and Å method in women was r = 0.64 and r = 0.58, respectively and in men r = 0.44 and r = 0.44, respectively. In women, the mean difference between estimated and measured VO2max was - 0.02 L min-1 (95% CI - 0.08 to 0.04) for the EB method and - 0.12 L min-1 (95% CI - 0.22 to - 0.02) for the Å method. Corresponding values for men were 0.05 L min-1 (95% CI - 0.04 to 0.14) and - 0.28 L min-1 (95% CI - 0.42 to - 0.14), respectively. However, the EB method was found to overestimate VO2max in men with low fitness and the Å method was found to underestimate VO2max in both women and men. For women, the coefficient of variance was 11.1%, when using the EB method and 19.8% when using the Å method. Corresponding values for men were 11.6% and 18.9%, respectively. CONCLUSION: The submaximal EB-test is valid for estimating VO2max in elderly women, but not in all elderly men. The Å-test is not valid for estimating VO2max in the elderly.Mätning av det dagliga aktivitetsmönstretTräning för äldres hjärnhäls

The wolf in the tabloid press : - A critical discourse analysis

Sammanfattning Vi vill med denna uppsats beskriva hur tabloidpressens väljer att presentera verkligheten kring två medieföljetonger rörande varg. Den första sträcker sig över drygt tre år i början av 1990-talet och behandlar den riksbekanta vargtiken Ylva medan den andra behandlar två varghannar som rymde ur ett djurparkshägn på Kolmårdens djurpark vilka omskrivs under drygt en månad i början av 2007. Vi undersöker därmed två vitt skilda händelser som utspelar sig med drygt 14 års mellanrum. Under den första följetongen var människor inte så vana vid varg i det vilda, kanske även påverkade av folklore i attityderna till varg. Under den andra följetongen har vargen som djur till viss del tagit sig in i människors medvetande och de flesta vet att det förekommer varg i Sverige, trots att dessa individer var domesticerade och ursprungligen kom från fångenskap innan de rymde. Då vargen är ett mytomspunnet och debatterat rovdjur (de flesta människor har någon åsikt om varg) fann vi det intressant att studera vilken bild som cirkulerar i tabloidpressen. I och med att vi använder oss av teorier kring den sociala konstruktionen av verkligheten, semiotik samt (ideologi)kritisk diskursanalys anser vi oss rama in väsentliga delar i vår undersökning. Genom att ställa dessa teorier gentemot de fakta som finns tillgänglig om vargen som biologisk och fungerande varelse kan vi tolka tabloidpressens intentioner ur ett ideologikritiskt perspektiv. Vi diskuterar kring sättet medierna (Aftonbladet och Expressen) konstituerar vår verklighet. Dels genom ordval som ibland kan kopplas till folklore som noanamnen vilka personifierar individer i artikelföljetongerna men också genom semiotiska förtecken samt vilka aktörer som tillåts träda fram. Slutligen något om vilka dolda ideologier (exempelvis medias makt gentemot läsare och lagstiftning) som kan finnas i bakgrunden. När det gäller resultatet fick vi tydligt motbevisat att ytterligheterna (aktörerna – klart pro respektive klart kontra varg) inte framträdde som frontfigurer i följetongerna. Vidare väntade vi oss i resultatet mer framträdande negativa konnotationer i framställandet av vargen. Negativa konnotationer fann vi, men inte så synliga som vi hade förväntat oss.Abstract With this essay we aim to describe how the tabloid press chooses to show the reality around two separated serial articles concerning wolves. The first serial takes place in the beginning of the 1990th and involves an uncultivated female wolf in Wermland – famously known as Ylva. The second serial takes place in the spring 2007 during a month’s time concerning two male wolves that escaped from Kolmårdens zoo. Both occasions are separated in time and have 14 years in between. During the first serial of articles we assume that common people weren’t used to uncultivated wolves. Maybe they were also effected by folklore in their attitudes to wolf. During the second serial of articles, concerning wolves, the animal has become more integrated in peoples minds and most people know that it occurs wolves in Sweden. Even though these two particular individuals were domesticated when they escaped. We found it interesting to examine how the tabloid press illustrate the wolves, because almost everyone has an opinion about wolf. The theories we use involves how the reality are constructed, semiotics and (ideological) critical discourse analysis. These theories, we believe, frames essential parts in our examination. By putting these theories against facts about the wolf as an animal we can interpret the tabloid presses intentions from an ideological critical perspective. Our discussion is about how the media (Aftonbladet and Expressen) constitutes our reality, through choices of words that sometimes can be connected to folklore. For example personalizes the individuals in the serials, by giving them so called “noanamn”, but we can also interpret through the semiotics sign and the operators that are aloud to “step forward”. Finally we examine which ideologies (for example media’s power against readers and legislation) are hidden in the context. Our result of this examination clearly shows that the persons with extreme opinions (operators – clearly pro or contra) weren’t frontfigures in the papers articles. We expected to find more salient negative connotations about wolves. We found negative opinions, but not as visible as we had expected