138 research outputs found

    High Intensity Interval Training for Maximizing Health Outcomes

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    Author's accepted version (post-print).Regular physical activity and exercise training are important actions to improve cardiorespiratory fitness and maintain health throughout life. There is solid evidence that exercise is an effective preventative strategy against at least 25 medical conditions, including cardiovascular disease, stroke, hypertension, colon and breast cancer, and type 2 diabetes. Traditionally, endurance exercise training (ET) to improve health related outcomes has consisted of low- to moderate ET intensity. However, a growing body of evidence suggests that higher exercise intensities may be superior to moderate intensity for maximizing health outcomes. The primary objective of this review is to discuss how aerobic high-intensity interval training (HIIT) as compared to moderate continuous training may maximize outcomes, and to provide practical advices for successful clinical and home-based HIIT.acceptedVersio

    Temporal ambivalences in smartphone use: Conflicting flows, conflicting responsibilities

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    This article explores implications of the central position of the smartphone in an age of constant connectivity. Based on a qualitative study of 50 informants, we ask how users experience and handle temporal ambivalences in everyday smartphone use, drawing on the concepts flow and responsibilization to conceptualize central dimensions of such ambivalences. The notion of conflicting flows illuminates how brief checking cycles expand at the expense of other activities, resulting in a temporal conflict experienced by users. Responsibilization points to how users take individual responsibility for managing such conflicting flows, and to how this practice is difficult and conflict-ridden. We conclude that while individual time management is often framed as the solution to temporal conflicts, such attempts at regulating smartphone use appear inadequate. Our conceptualization of temporal ambivalence offers a more nuanced understanding of why this is the case.publishedVersio

    Intensity Control During Block-Periodized High-Intensity Training : Heart Rate and Lactate Concentration During Three Annual Seasons in World-Class Cross-Country Skiers

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    Purpose: To describe heart rate (HR) and blood lactate (Bla−) responses during high-intensity interval training (HIT) in a long-term block-periodized HIT regimen in world-class cross-country (XC) skiers. Methods: Data were collected in 14 world-class female XC skiers (aged 25 ± 5 years; body mass, 60.4 ± 6.5 kg; and maximal HR, 194 ± 8 beats · min−1) throughout three entire seasons. The HR and Bla− values were determined at the end of 572 intervals performed during 63 sessions and 17 HIT blocks utilizing different exercise modes: running, running with poles, and skiing (on-snow and roller ski) with classic and skating techniques. Results: The mean HR was 91 ± 3% of HRmax with a corresponding Bla− of 7.3 ± 2.1 mmol · L−1. The average HR and Bla− values were relatively similar across the different exercise modes, except for a lower HR (~90 vs. 92% of HRmax) for on-snow and roller ski classical skiing and lower Bla− values (5.9 vs. 7.0–7.8 mmol · L−1) for on-snow classical skiing compared to the other modes, both P < 0.05. An increase in HR and Bla− was observed from interval working periods 1 to 3 (90–92% of HRmax and 6.5–7.7 mmol · L−1) and further from 3 to 5 (92–93% of HRmax and 7.7–9.0 mmol · L−1), all P < 0.05. Conclusions: We describe long-term use of HIT-block periodization among world-class XC skiers who achieved target HR and Bla− levels in all six exercise modes employed. According to athletes and coaches, the key to successful blocks was intensity control to allow for high-quality HIT sessions throughout the entire HIT block.publishedVersionUnit Licence Agreemen

    No Effect of Calanus Oil on Maximal Oxygen Uptake in Healthy Participants: A Randomized Controlled Study

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    We aimed to investigate the long-term effect of daily Calanus oil supplementation on maximal oxygen uptake (VO2max) in healthy 30- to 50-year-old participants. The study was motivated by preclinical studies reporting increased VO2max and metabolic health with omega-3 rich Calanus oil. In a double-blinded study, 71 participants were randomized to receive 2 g/day of Calanus or placebo supplementation for a total of 6 months. The participants underwent exercise testing and clinical investigations at baseline, 3 months, and 6 months. Main study endpoint was change in VO2max from baseline to 6 months. Fifty-eight participants completed the 6-month test and were included in the final data analysis (age: Calanus, 39.7 [38.0, 41.4] and placebo, 38.8 [36.8, 40.9] years; body mass index: Calanus, 24.8 [24.0, 25.6] and placebo, 24.8 [23.7, 25.8] kg/m2; and VO2max: Calanus, 50.4 [47.1, 53.8] and placebo, 50.2 [47.2, 53.1] ml·kg−1·min−1). There were no between-group differences at baseline, nor were there any between-group differences in absolute (Calanus, 3.74 [3.44, 4.04] and placebo, 3.79 [3.44, 4.14] L/min) or relative VO2max (Calanus, 49.7 [46.2, 53.2] and placebo, 49.5 [46.0, 53.1] ml·kg−1·min−1) at 6 months (mean [95% confidence interval]). There were no between-groups change in clinical measures from baseline to 3 and 6 months. In conclusion, VO2max was unaffected by 6 months of daily Calanus oil supplementation in healthy, physically fit, normal to overweight men and women between 30 and 50 years old

    Discrepancy between cardiorespiratory system and skeletal muscle in elite cyclists after hypoxic training

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    BACKGROUND: The purpose of this study was to determine the effects of hypoxic training on the cardiorespiratory system and skeletal muscle among well-trained endurance athletes in a randomized cross-over design. METHODS: Eight junior national level competitive cyclists were separated into two groups; Group A trained under normoxic condition (21% O(2)) for 2 hours/day, 3 days/week for 3 weeks while Group B used the same training protocol under hypoxic condition (15% O(2)). After 3 weeks of each initial training condition, five weeks of self-training under usual field conditions intervened before the training condition was switched from NT to HT in Group A, from HT to NT in Group B. The subjects were tested at sea level before and after each training period. O(2 )uptake ([Image: see text] O(2)), blood samples, and muscle deoxygenation were measured during bicycle exercise test. RESULTS AND DISCUSSION: No changes in maximal workload, arterial O(2 )content, [Image: see text] O(2 )at lactate threshold and [Image: see text] O(2max )were observed before or after each training period. In contrast, deoxygenation change during submaximal exercise in the vastus lateralis was significantly higher at HT than NT (p < 0.01). In addition, half time of oxygenation recovery was significantly faster after HT (13.2 ± 2.6 sec) than NT (18.8 ± 2.7 sec) (p < 0.001). CONCLUSIONS: Three weeks of HT may not give an additional performance benefit at sea level for elite competitive cyclists, even though HT may induce some physiological adaptations on muscle tissue level

    Ossification of Atlantic cod (Gadus morhua) – Developmental stages revisited

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    In studies of marine larvae, it is common to use days post-hatch as a developmental reference point. We show that age is a poor measure of morphological and physiological development in Atlantic cod. Therefore, we propose a set of five developmental stages of Atlantic cod fromstart-feeding until the juvenile stage, based on cranial ossification as previously done in Atlantic halibut. Cod follows a sequence of cranial ossification that is to a large extent preserved in most fish species examined. These stages are therefore tools to standardize sampling and to reduce growth dependent variation in the analysis of larvae during development. Weshow that several developmental stages are present in the same rearing unit at a given time. We also demonstrate that nutrition during early development is a vital foundation for robust skeletal development. Cod larvae supplied with copepods instead of rotifers followed by Artemia, develop less skeletal deformities at 10 cm standard length, despite given the same formulated feed from 1.8 cm standard length and onwards. Statement of relevance: This paper provides developmental stages that are vital for best practice protocols in aquaculture. By relating farming practices to developmental stages and not age, the right treatment ect may be provided. This manuscript does also highlight the importance of nutrition during live feed stages on events that may occur late in the production cycle.acceptedVersio

    The Relentless Attempt to Perfect the 2-Stent Technique∗

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    <p><b>Individual data points for one repetition maximum before (a) and after the intervention period (b) and for average power at 40% of one repetition maximum before (c) and after the intervention period (d) for the upper-body sprint-interval training group (SIG) and the control group (CG).</b> Mean values are represented by the thick line with black circles. Significant within-group changes: *p<0.05, **p<0.001; Significant different change from pre to post between groups: <sup>#</sup>p<0.05.</p
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