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- Hansen, Mette, et al.
(författare)
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The female handball player
- 2018. - 1
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Ingår i: Handball Sports Medicine. - : Springer. - 9783662558911 - 9783662558928 ; , s. 553-570
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Bokkapitel (refereegranskat)
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| 2. |
- Hanstock, Helen, 1989-, et al.
(författare)
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Influence of interval duration on immunological responses to 4-weeks’ high-intensity interval training
- 2018
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Ingår i: Journal of Sports Sciences. - : Routledge. - 0264-0414 .- 1466-447X. ; , s. 1-94
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Konferensbidrag (refereegranskat)abstract
- High-intensity interval training (HIT) encompasses a wide range of training prescriptions where up to nine variables can be manipulated (Buchheit and Laursen, 2013, Sports Medicine, 43(5), 313–338). Four weeks of HIT with longer intervals and accumulated work durations (AWD) has been shown to elicit greater improvements in peak oxygen consumption (V O 2peak ) despite more modest physiological, hormonal and perceptual responses (Sylta et al., 2017, Medicine & Science in Sports & Exercise, 49(6), 1137–1146). However, immunological responses to different HIT pre- scriptions have rarely been investigated. The purpose of this study was to compare the cumulative effects of a four-week HIT intervention, performed either as short or long intervals with the same AWD, on V O 2peak , the immunological biomarker salivary secretory IgA (s-IgA) and upper respiratory illness (URI) incidence. In addition, we explored the influence of HIT on serum cortisol, testosterone, 25(OH)D and ferritin as biomarkers related to immune competence. Following local ethics committee approval, twenty-five well-trained male cyclists and triath- letes provided written consent to take part and were randomised to one of three HIT groups (Long Intervals [LI]: 4 × 8min; Short Intervals 1 [SI1]: 4×[12 × 40/20s]; Short Intervals 2 [SI2]: 4×[8 ×40/20s]). Participants per- formed three cycling HIT sessions per week for four weeks at maximal session effort (“isoeffort”) intensity, supplemented with ad libitumlow-intensity training. Participants recorded upper respiratory symptoms (URS) daily using the Jackson Common Cold Scale; episodes of URI were identified retrospectively. V O 2peak as well as rested saliva and blood biomarkers were analysed before and after the training period. Fourteen of twenty-five participants reported an episode of URI (LI: 4/8, SI1: 4/8, SI2: 6/9) but there were no differences in URI incidence, severity or duration between groups. Following the train- ing intervention, we observed a moderate increase in V O 2peak across the cohort (mean± SD: 4.75 ± 0.42 to 4.86 ± 0.43 L· min−1 ,Cohen’s d= 0.65, 90% confidence intervals: [0.16, 1.13]) but the change in V O 2peak was not different between groups. Serum cortisol displayed a moderate increase (367 ± 98 to 415 ± 108 nmol· L −1 ,d=0.60 [0.12, 1.08]) and 25(OH)D a large decrease (79.2 ± 17.1 to 70.4 ± 17.6 nmol· L −1 ,d= -0.87 [−1.36,−0.37]) from pre- to post-training, but there were no differences in the magnitude of the responses between groups. Four weeks’HIT did not influence s-IgA secretion rate, serum testosterone or ferritin. We conclude that four weeks’ AWD-matched HIT performed as short- or long-intervals at isoeffort intensity does not differentially influence ill- ness incidence, immunological responses to training nor other immune-related biomarkers. This observation can be viewed as a positive finding for training planning, since it could allow coaches some flexibility in constructing AWD-matched isoeffort HIT sessions to achieve performance goals, without concern about detrimental effects on athletes’ immune status.
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| 3. |
- Hanstock, Helen, 1989-, et al.
(författare)
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Evaluation of physiological and nutritional risk factors for upper respiratory illness using a zero-inflated negative binomial model
- 2018
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Ingår i: Journal of Sports Sciences. - : Routledge. - 0264-0414 .- 1466-447X. ; , s. 44-45
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Konferensbidrag (refereegranskat)abstract
- Intensified training periods may increase incidence of upper respiratory illness (URI) in athletes (Meeusen et al., 2013,Medicine and Science in Sports and Exercise, 45(1), 186–205). Many physiological and nutritional risk factors have beenassociated with increased risk of URI (Bermon et al., 2017, Exercise Immunology Review, 23, 8–50), including reductionsin salivary IgA (sIgA), elevated cortisol, vitamin D insufficiency, iron deficiency and low energy availability (EA). However, few studies have explored the relative importance of each of thesehealth-related biomarkers in a multivariate model. Our aimwas therefore to investigate the relationship between multiplebiological risk factors for illness and incidence, duration andseverity of URIs that present during intensified training. 3815Twenty-five well-trained male cyclists and triathletes (age 30 ± 9 y, VO2peak 64 ± mL· kg−1· min−1) performed one ofthree different high-intensity interval training (HIT) programmes for three sessions per week over four weeks in November-December. The study received local ethical approval and participants provided written, informed consentto participate. Participants performed each HIT session at “isoeffort” intensity and sessions were matched for total accumulated work duration. Participants logged upper respiratorysymptoms (URS) daily using the Jackson Common Cold Scale; episodes of URI were identified retrospectively using the followinga priori criteria: weekly symptom score > 14 or selfreportedcommon cold for > 2 consecutive days (Jacksonet al., 1958, American Medical Association Archives of Internal Medicine, 101, 267–278). Before commencing the training period, VO2peak was determined using an incremental maximal cycling protocol and participants provided rested, fasted blood and saliva samples prior to the training period foranalysis of plasma 25(OH)D, ferritin, cortisol, testosterone and sIgA secretion rate. EA was calculated based on a 3-day registration of energy intake and expenditure relative to fat-free mass measured in a rested, fasted state using indirect calorimetry (Torstveit et al., 2018 February, International Journal of Sport Nutrition and Exercise Metabolism, 1–28). We used a zero-inflated negative binomial model to investigate the relationship between baseline VO2peak, health-related biomarkers and URI incidence/duration/global URS severity. Fourteen athletes(56%) reported an episode of URI during the four-week monitoring period. Higher sIgA was associated with reduced risk of URI (odds ratio = 0.90, 90% confidence interval (CI): [0.83,0.97]). Lower plasma cortisol (P = 0.02) and higher EA (P = 0.02) were associated with longer URI duration; holding cortisol constant, the incidence risk ratio (IRR) for a one-unit increase in EA was 1.04 (90% CI: [1.01, 1.07]). Participants with higher VO2peak reported higher total symptom scores during the intervention period (P = 0.03, IRR = 1.07, 90% CI: [1.01,1.13]). Several health-related biomarkers and physiological parameters may therefore be associated with risk and severityof URI, including sIgA, cortisol, EA and VO2peak.
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| 5. |
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| 6. |
- Torstveit, Monica Klungland, et al.
(författare)
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Within-Day Energy Deficiency and Metabolic Perturbation in Male Endurance Athletes
- 2018
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Ingår i: International Journal of Sport Nutrition & Exercise Metabolism. - : Human Kinetics. - 1526-484X .- 1543-2742. ; 28:4, s. 419-427
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Tidskriftsartikel (refereegranskat)abstract
- Endurance athletes are at increased risk of relative energy deficiency associated with metabolic perturbation and impaired health. We aimed to estimate and compare within-day energy balance in male athletes with suppressed and normal resting metabolic rate (RMR) and explore whether within-day energy deficiency is associated with endocrine markers of energy deficiency. A total of 31 male cyclists, triathletes, and long-distance runners recruited from regional competitive sports clubs were included. The protocol comprised measurements of RMR by ventilated hood and energy intake and energy expenditure to predict RMR-ratio (measured RMR/predicted RMR), energy availability, 24-hr energy balance and within-day energy balance in 1-hr intervals, assessment of body composition by dual-energy X-ray absorptiometry, and blood plasma analysis. Subjects were categorized as having suppressed (RMRratio < 0.90, n = 20) or normal (RMRratio > 0.90, n = 11) RMR. Despite there being no observed differences in 24-hr energy balance or energy availability between the groups, subjects with suppressed RMR spent more time in an energy deficit exceeding 400 kcal (20.9 [18.8-21.8] hr vs. 10.8 [2.5-16.4], p =.023) and had larger single-hour energy deficits compared with subjects with normal RMR (3,265 +/- 1,963 kcal vs. -1,340 +/- 2,439, p =.023). Larger single-hour energy deficits were associated with higher cortisol levels (r = -.499, p =.004) and a lower testosterone: cortisol ratio (r =.431, p =.015), but no associations with triiodothyronine or fasting blood glucose were observed. In conclusion, within-day energy deficiency was associated with suppressed RMR and catabolic markers in male endurance athletes.
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