Effekten antioksidanttilskudd har på maksimalt oksygenopptak, arbeidsøkonomi og blod etter en periode med utholdenhetstrening hos utrente personer: Hvilken effekt har daglig tilskudd med vitamin C og vitamin E, kombinert utholdenhetstrening på adaptasjonen i det kardiovaskulære systemet hos utrente personer

Under trening øker dannelsen av frie radikaler og andre reaktive oksygenforbindelser (ROS). Det kan se ut som at generering av frie radikaler og ROS i muskelcellene kan bidra i den cellulære signaleringen som er forbundet med treningstilpasninger (f.eks. økt aerobe kapasiteten). Antioksidanter er nødvendig å beskytte cellene mot oksidative skader ved å kontrollere nivåene av frie radikaler og ROS. Dermed kan det tenkes at tilskudd med store mengde antioksidanter kan redusere nivåene av ROS så kraftig at det kan ha negativ effekt på tilpasningene som normalt skjer ved utholdenhetstrening. C- og E-vitamin er de to mest kjente og brukte eksogene antioksidantene, og som ofte benyttes som kosttilskudd. Hensikten med denne studien var derfor å undersøke hvilke effekt store, daglige doser C- og E-vitamin har på treningstilpasningene til aerob utholdenhetstrening

Force-velocity profiling in athletes: Reliability and agreement across methods

publishedVersio

Strength and Power Testing of Athletes: A Multicenter Study of Test-Retest Reliability

Author's accepted manuscriptAccepted author manuscript version reprinted, by permission, from International Journal of Sports Physiology and Performance (IJSPP), 2022, 17 (7): 1103-1110, https://doi.org/10.1123/ijspp.2021-0558. © Human Kinetics, Inc.Purpose:This study examined the test–retest reliability of common assessments for measuring strength and power of the lowerbody in high-performing athletes.Methods:A total of 100 participants, including both male (n=83) and female (n=17) athletes(21 [4] y, 182 [9] cm, and 78 [12] kg), were recruited for this study, using a multicenter approach. The participants underwentphysical testing 4 times. Thefirst 2 sessions (1 and 2) were separated by∼1 week, followed by a period of 2 to 6 months, whereasthe last 2 sessions (3 and 4) were again separated by∼1 week. The test protocol consisted of squat jumps, countermovementjumps, jump and reach, 30-m sprint, 1-repetition-maximum squat, sprint cycling, and a leg-press test.Results:The typical error(%) ranged from 1.3% to 8.5% for all assessments. The change in means ranged from−1.5% to 2.5% for all assessments, whereasthe interclass correlation coefficient ranged from .85 to .97. The smallest worthwhile change (0.2 of baseline SD) ranged from1.2% to 5.0%. The ratio between the typical error (%) and the smallest worthwhile change (%) ranged from 0.5 to 1.2. Whenobserving the reliability across testing centers, considerable differences in reliability were observed (typical error [%] ratio: 0.44–1.44).Conclusions:Most of the included assessments can be used with confidence by researchers and coaches to measurestrength and power in athletes. Our results highlight the importance of controlling testing reliability at each testing center and notrelying on data from others, despite having applied the same protocol.acceptedVersio

Parental Smoking and Risk of Childhood-onset Type 1 Diabetes

Background: A few prospective studies suggest an association between maternal smoking during pregnancy and lower risk of type 1 diabetes. However, the role of unmeasured confounding and misclassification remains unclear. Methods: We comprehensively evaluated whether maternal smoking in pregnancy predicts lower risk of childhood-onset type 1 diabetes in two Scandinavian pregnancy cohorts (185,076 children; 689 cases) and a Norwegian register-based cohort (434,627 children; 692 cases). We measured cord blood cotinine as an objective marker of nicotine exposure during late pregnancy in 154 cases and 476 controls. We also examined paternal smoking during pregnancy, in addition to environmental tobacco smoke exposure the first 6 months of life, to clarify the role of characteristics of smokers in general. Results: In the pregnancy cohorts, maternal smoking beyond gestational week 12 was inversely associated with type 1 diabetes, pooled adjusted hazard ratio (aHR) 0.66 (95% CI = 0.51, 0.85). Similarly, in the Norwegian register-based cohort, children of mothers who still smoked at the end of pregnancy had lower risk of type 1 diabetes, aHR 0.65 (95% CI = 0.47, 0.89). Cord blood cotinine >=30 nmol/L was also associated with reduced risk of type 1 diabetes, adjusted odds ratio 0.42 (95% CI = 0.17, 1.0). We observed no associations of paternal smoking during pregnancy, or environmental tobacco smoke exposure, with childhood-onset type 1 diabetes. Conclusion: Maternal sustained smoking during pregnancy is associated with lower risk of type 1 diabetes in children. This sheds new light on the potential intrauterine environmental origins of the disease

A strength-oriented exercise session required more recovery time than a power-oriented exercise session with equal work

The present randomized cross-over controlled study aimed to compare the rate of recovery from a strength-oriented exercise session vs. a power-oriented session with equal work. Sixteen strength-trained individuals conducted one strength-oriented session (five repetitions maximum (RM)) and one power-oriented session (50% of 5RM) in randomized order. Squat jump (SJ), countermovement jump (CMJ), 20-m sprint, and squat and bench press peak power and estimated 1RMs were combined with measures of rate of perceived exertion (RPE) and perceived recovery status (PRS), before, immediately after and 24 and 48 h after exercise. Both sessions induced trivial to moderate performance decrements in all variables. Small reductions in CMJ height were observed immediately after both the strength-oriented session (7 ± 6%) and power-oriented session (5 ± 5%). Between 24 and 48 h after both sessions CMJ and SJ heights and 20 m sprint were back to baseline. However, in contrast to the power-oriented session, recovery was not complete 48 h after the strength-oriented session, as indicated by greater impairments in CMJ eccentric and concentric peak forces, SJ rate of force development (RFD) and squat peak power. In agreement with the objective performance measurements, RPE and PRS ratings demonstrated that the strength-oriented session was experienced more strenuous than the power-oriented session. However, these subjective measurements agreed poorly with performance measurements at the individual level. In conclusion, we observed a larger degree of neuromuscular impairment and longer recovery times after a strength-oriented session than after a power-oriented session with equal total work, measured by both objective and subjective assessments. Nonetheless, most differences were small or trivial after either session. It appears necessary to combine several tests and within-test analyses (e.g., CMJ height, power and force) to reveal such differences. Objective and subjective assessments of fatigue and recovery cannot be used interchangeably; rather they should be combined to give a meaningful status for an individual in the days after a resistance exercise session