Ida Siobhan Svendsen

The present study explored the impact of pre-altitude serum (s)-ferritin and iron supplementation on changes in hemoglobin mass (Delta Hbmass) following altitude training. Measures of Hbmass and s-ferritin from 107 altitude sojourns (9-28 days at 1800-2500 m) with world-class endurance athletes (males n = 41, females n = 25) were analyzed together with iron supplementation and self-reported illness. Altitude sojourns with a hypoxic dose [median (range)] of 1169 (912) km center dot h increased Hbmass (mean +/- SD) 36 +/- 38 g (3.7 +/- 3.7%, p < 0.001) and decreased s-ferritin -11 (190) mu g center dot L-1 (p = 0.001). Iron supplements [27 (191) mg center dot day(-1)] were used at 45 sojourns (42%), while only 11 sojourns (10%) were commenced with s-ferritin 100 mu g center dot L-1, respectively, with no group difference (p = 0.400). Hbmass increased by 4.1 +/- 3.9%, 3.0 +/- 3.0% and 3.7 +/- 4.7% without, <= 50 mg center dot day(-1) or >50 mg center dot day(-1) supplemental iron, respectively (p = 0.399). Linear mixed model analysis revealed no interaction between pre-altitude s-ferritin and iron supplementation on Delta Hbmass (p = 0.906). However, each 100 km center dot h increase in hypoxic dose augmented Delta Hbmass by an additional 0.4% (95% CI: 0.1-0.7%; p = 0.012), while each 1 g center dot kg(-1) higher pre-altitude Hbmass reduced Delta Hbmass by -1% (-1.6 to -0.5; p < 0.001), and illness lowered Delta Hbmass by -5.7% (-8.3 to -3.1%; p < 0.001). In conclusion, pre-altitude s-ferritin or iron supplementation were not related to the altitude-induced increase in Hbmass (3.7%) in world-class endurance athletes with clinically normal iron stores.

Performing at an elite level in Nordic combined (NC) requires both the explosiveness required for ski jumping performance and the endurance capacity required for cross-country skiing.Purpose: : To describe the characteristics of world-class NC athletes’ training and determine how endurance and non–endurance (ie, strength, power, and ski jumping) training is periodized.Methods: : Annual training characteristics and the periodization of endurance and non–endurance training were determined by analyzing the training diaries of 6 world-class NC athletes.Results: : Of 846 ± 72 annual training hours, 540 ± 37 h were endurance training, with 88.6% being low-, 5.9% moderate-, and 5.5% high-intensity training. While training frequency remained relatively constant, the total training volume was reduced from the general preparatory to the competition phase, primarily due to less low- and moderate-intensity training (P < .05). A total of 236 ± 55 h/y were spent as non–endurance training, including 211 ± 44 h of power and ski-jump-specific training (908 ± 165 ski jumps and ski-jump imitations). The proportion of non–endurance training increased significantly toward the competition phase (P < .05).Conclusion: : World-class NC athletes reduce the volume of low- and moderate-intensity endurance training toward the competition phase, followed by an increase in the relative contribution of power and ski-jump training. These data provide novel insight on how successful athletes execute their training and may facilitate more-precise coaching of future athletes in this sport. In addition, this information is of high relevance for the training organization of other sports that require optimization of 2 fundamentally different physical capacities.

To determine how immune markers are affected by acute hypoxic exercise at the same relative intensity.

Free light chains (FLCs) have a range of biological functions and may act as a broad marker of immunesuppression and activation and inflammation. Measurement of salivary FLCs may provide practical advantages in a range of clinical populations. The aim of the present study was to develop normal reference ranges of FLCs in saliva and assess the effects of acute exercise on FLC levels in younger and older adults. Saliva FLC concentrations and secretion rates were measuredin young (n = 88, aged 18-36) and older (n = 53, aged 60-80) adults. To assess FLC changes in response to acute exercise, young adults completed a constant work-rate cycling exercise trial at 60% VO2max (n = 18) or a 1 h cycling time trial (TT) (n = 10) and older adults completed an incremental submaximal treadmill walking exercise test to 75% HRmax (n = 53). Serum FLCs were measured at baseline and in response to exercise. Older adults demonstrated significantly higher levels of salivary FLC parameters compared with young adults. Median (5-95th percentile) concentrationswere 0.45 (0.004- 3.45) mg/L for kappa and 0.30 (0.08-1.54) mg/L for lambda in young adults; 3.91 (0.75-19.65) mg/L for kappa and 1.00 (0.02-4.50) mg/L for lambda in older ad ults. Overall median concentrations of salivary kappa and lambda FLCs were 10-fold and 20-fold lower than serum, respectively. Reductions in salivary FLC concentrations and secretion rates were observed immediately post- and at 1 h post exercise, but were only significant for the older cohort; FLCs began to recover between post and 1 h post-exercise. No changes in serum FLCs were observed in response to exercise.

The aim of this study was to determine whether participating in a cross‐country skiing stage race (Tour deSki;TDS) affects subsequent illness incidence, training, and race performance. Self‐reported training and illness data from 44 male and female elite cross‐country skiers were included. In total, 127 years of data were collected (2–3 seasons per athlete). Illness incidence, training load, and performance in international competitions were calculated for athletes who did and did not participate inTDS. Forty‐eight percent of athletes reported becoming ill during or in the days immediately after taking part inTDSvs 16% of athletes who did not participate. In both groups, illness incidence was somewhat lower for female athletes. For male athletes, race performance was significantly worse for 6 weeks followingTDSvs 6 weeks beforeTDS. Furthermore, while female athletes who participated inTDSperformed relatively better than controls inOlympics/WorldChampionships, male athletes who participated inTDStypically performed worse in subsequent major championships. Participating inTDSappears to result in ∼ 3‐fold increase in risk of illness in this period. Male athletes appear more prone to illness and also see a drop in race performance followingTDS, possibly linked to differences in training load before and after the event.