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- Karlsson, Øyvind, 1989-, et al.
(författare)
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Exercise Intensity During Cross-Country Skiing Described by Oxygen Demands in Flat and Uphill Terrain
- 2018
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Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: In this study wearable global navigation satellite system units were used on athletes to investigate pacing patterns by describing exercise intensities in flat and uphill terrain during a simulated cross-country ski race.Methods: Eight well-trained male skiers (age: 23.0 ± 4.8 years, height: 183.8 ± 6.8 cm, weight: 77.1 ± 6.1 kg, VO2peak: 73 ± 5 mL⋅kg-1⋅min-1) completed a 13.5-km individual time trial outdoors and a standardized indoor treadmill protocol on roller skis. Positional data were recorded during the time trial using a differential global navigation satellite system to calculate external workloads in flat and uphill terrain. From treadmill tests, the individual relationships between oxygen consumption and external workload in flat (1°) and uphill (8°) terrain were determined, in addition to VO2peak and the maximal accumulated O2-deficit. To estimate the exercise intensity in the time trial, the O2-demand in two different flat and five different uphill sections was calculated by extrapolation of individual O2-consumption/workload ratios.Results: There was a significant interaction between section and average O2-demands, with higher O2-demands in the uphill sections (110–160% of VO2peak) than in the flat sections (≤100% of VO2peak) (p < 0.01). The maximal accumulated O2-deficit associated with uphill treadmill roller skiing was significantly higher compared to flat (6.2 ± 0.5 vs. 4.6 ± 0.5 L, p < 0.01), while no significant difference was found in VO2peak.Conclusion: Cross-country (XC) skiers repeatedly applied exercise intensities exceeding their maximal aerobic power. ΣO2-deficits were higher during uphill skiing compared to flat which has implications for the duration and magnitude of supramaximal work rates that can be applied in different types of terrain.
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- Karlsson, Øyvind, 1989-, et al.
(författare)
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Metabolic Phenotyping from Whole-Blood Responses to a Standardized Exercise Test May Discriminate for Physiological, Performance, and Illness Outcomes : A Pilot Study in Highly-Trained Cross-Country Skiers
- 2024
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Ingår i: Sports Medicine - Open. - : Springer Nature. - 2199-1170 .- 2198-9761. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: This study used metabolic phenotyping to explore the responses of highly-trained cross-country skiers to a standardized exercise test, which was part of the athletes' routine testing, and determine whether metabolic phenotyping could discriminate specific physiological, performance, and illness characteristics.METHODS: Twenty-three highly-trained cross-country skiers (10 women and 13 men) participated in this study. Capillary whole-blood samples were collected before (at rest) and 2.5 min after (post-exercise) a roller-ski treadmill test consisting of 5-6 × 4-min submaximal stages followed by a self-paced time trial (~ 3 min) and analyzed using mass spectrometry. Performance level was defined by International Ski Federation distance and sprint rankings. Illness data were collected prospectively for 33 weeks using the Oslo Sports Trauma Research Center Questionnaire on Health Problems. Orthogonal partial least squares-discriminant analyses (OPLS-DA) followed by enrichment analyses were used to identify metabolic phenotypes of athlete groups with specific physiological, performance, and illness characteristics.RESULTS: Blood metabolite phenotypes were significantly different after the standardized exercise test compared to rest for metabolites involved in energy, purine, and nucleotide metabolism (all OPLS-DA p < 0.001). Acute changes in the metabolic phenotype from rest to post-exercise could discriminate athletes with: (1) higher vs. lower peak blood lactate concentrations; (2) superior vs. inferior performance levels in sprint skiing, and (3) ≥ 2 vs. ≤ 1 self-reported illness episodes in the 33-week study period (all p < 0.05). The most important metabolites contributing to the distinction of groups according to (1) post-exercise blood lactate concentrations, (2) sprint performance, and (3) illness frequency were: (1) inosine, hypoxanthine, and deoxycholic acid, (2) sorbitol, adenosine monophosphate, and 2-hydroxyleuroylcarnitine, and (3) glucose-6-phosphate, squalene, and deoxycholic acid, respectively.CONCLUSION: Metabolic phenotyping discriminated between athlete groups with higher vs. lower post-exercise blood lactate concentrations, superior vs. inferior sprint skiing performance, and more vs. less self-reported illnesses. While the biological relevance of the identified biomarkers requires validation in future research, metabolic phenotyping shows promise as a tool for routine monitoring of highly-trained endurance athletes.
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- Danemar, Magnus, et al.
(författare)
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The associations between health problems and performance in elite cross-country skiers
- 2020
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Konferensbidrag (refereegranskat)abstract
- Purpose: The aim of this study was to examine the relationships between health problems, defined as injury or illness, on performance during a competitive season among elite XC skiers (9 females; 9 males).Methods: Data was collected for 17 weeks using the Oslo Sports Trauma Research Center questionnaire on health problems, resulting in a total of 296 athlete weeks’ worth of data. Prevalence and severity measures were calculated for all health problems and substantial health problems (defined as problems leading to moderate or severe reductions in training volume or sports performance, or complete inability to participate). Acssociations between health problems and performance were analyzed using regressions with change in FIS points from the 2018/19 season to the 2019/20 season, representing performance.Results: The average weekly prevalence of all health problems was 19% (95% CI: 3.5% to 34%). Prevalence of substantial health problems was 12% (95% CI: -0.4% to 25%). Illness was the most common health problem, representing 74 days (71%) of total time loss compared to overuse injuries (12 days, 12%) and acute injuries (18 days, 17%). There was no significant association between the cumulative severity score of health problems (-0.03; 95% CI: -0.08 to 0.02; p = 0.25).Conclusions: No relationship was identified between the cumulative severity of health problems and performance.Practical applications: The findings from this study suggest that ongoing surveillance programs could be useful in mapping athlete injury and illness trends.
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- Holmström, Pontus K., et al.
(författare)
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Enhanced splenic volume and contraction in elite endurance athletes
- 2021
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Ingår i: Journal of applied physiology. - : American Physiological Society. - 8750-7587 .- 1522-1601. ; 131:2, s. 474-486
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Tidskriftsartikel (refereegranskat)abstract
- Splenic contraction, which leads to ejection of stored erythrocytes, is greater in athletes involved in regular freediving or high-altitude activities. As this response facilitates oxygen-carrying capacity, similar characteristics may be expected of elite endurance athletes. Therefore, our aims were to compare resting and apnea-induced splenic volume in endurance athletes and untrained individuals, and to assess the athletes' exercise-induced splenic volume. Twelve elite biathletes (7 women) and 12 controls (6 women) performed a maximal effort apnea in a seated position. In addition, the biathletes completed a maximal roller-skiing time trial. Splenic dimensions were measured by ultrasonic imaging for subsequent volume calculations, whereas Hb was analyzed from capillary blood samples and cardiorespiratory variables were monitored continuously. Baseline splenic volume was larger in the biathletes (214 +/- 56 mL) compared with controls (157 +/- 39 mL, P = 0.008) and apnea-induced splenic contraction was also greater in the biathletes (46 +/- 20 mL vs. 30 +/- 16 mL, P = 0.035). Hb increased immediately after apnea in the biathletes (4.5 +/- 4.8%, P = 0.029) but not in the controls (-0.7 +/- 3.1%, P = 0.999). Increases in exercise-induced splenic contraction (P = 0.008) and Hb (P = 0.001) were greater compared with the apnea-induced responses among the athletes. Baseline splenic volume tended to be correlated with <(V)over dot>o(2max) (r= 0.584, P = 0.059). We conclude that elite biathletes have greater splenic volume with a greater ability to contract and elevate Hb compared with untrained individuals. These characteristics may transiently enhance O-2-carrying capacity and possibly increase O-2 uptake, thereby helping biathletes to cope with high intermittent O-2 demands and severe O-2 deficits that occur during biathlon training and competition. NEW & NOTEWORTHY This study demonstrates that elite biathletes have larger splenic volume, apnea-induced splenic contraction, and Hb elevation compared with untrained individuals, which is likely functional to cope with high O-2 demands and substantial O-2 deficits. We believe that enhanced splenic contraction may be of importance during competitions involving crosscountry skiing, to regulate circulating Hb and enhance O-2-carrying capacity, which may protect Ca-O2, and increase O-2 uptake.
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| 7. |
- Holmström, Pontus, et al.
(författare)
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The effects of high altitude ascent on splenic contraction and the diving response during voluntary apnea
- 2021
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Ingår i: Experimental Physiology. - 0958-0670 .- 1469-445X. ; 106:1, s. 160-174
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Tidskriftsartikel (refereegranskat)abstract
- Voluntary apnea causes splenic contraction and reductions in heart rate (HR; bradycardia), and subsequent transient increases in hemoglobin concentration ([Hb]). Ascent to high altitude (HA) induces systemic hypoxia and reductions in oxygen saturation (SpO2 ), which may cause tonic splenic contraction, which may contribute to hematological acclimatization associated with HA ascent. We measured resting cardiorespiratory variables (HR, SpO2 , [Hb]) and resting splenic volume (via ultrasound) during incremental ascent from 1400 m (day 0), to 3440 m (day 3), 4240 m (day 7), and 5160 m (day 10) in non-acclimatized native lowlanders during assent to HA in the Nepal Himalaya. In addition, apnea-induced responses in HR, SpO2 and splenic volume were measured before and after two separate voluntary maximal apneas (A1-A2) at 1400 m, 3440 m and 4240 m. Resting spleen volume decreased -14.3% (-15.2 mL)/1000 m with ascent, from 140±41 mL (1400 m), to 108±28 mL (3440 m; P > 0.99), 94±22 mL (4240 m; P = 0.009) and 84±28 mL (5160 m; P = 0.029), with concomitant increases in [Hb] from 125±18.3 g/L (1400 m) to 128±10.4 g/L (3440 m), 138.8±12.7 g/L (4240 m) and 157.5±8 g/L (5160 m; P = 0.021). Apnea-induced splenic contraction was 50±15 mL (1400 m), 44±17 mL (3440 m; P > 0.99) and 26±8 mL (4240 m; P = 0.002), but was not consistently associated with increases in [Hb]. The apnea-induced bradycardia was more pronounced at 3440 m (A1:P = 0.04; A2:P = 0.094) and at 4240 m (A1:P = 0.037 A2:P = 0.006) compared to values at 1400 m. We conclude that hypoxia-induced splenic contraction at rest (a) may contribute to restoring arterial oxygen content through its [Hb]-enhancing contractile function and (b) eliminates further apnea-induced [Hb] increases in hypoxia. We suggest that tonic splenic contraction may contribute to hematological acclimatization early in HA ascent in humans.
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- Hrozanova, Maria, et al.
(författare)
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An observational study of sleep characteristics in elite endurance athletes during an altitude training camp at 1800 m
- 2021
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Ingår i: Sleep Health. - : Elsevier. - 2352-7218 .- 2352-7226. ; 7:6, s. 691-698
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Tidskriftsartikel (refereegranskat)abstract
- DesignProspective, observational.SettingBaseline monitoring at <500 m for 2 weeks and altitude monitoring at 1800 m for 17-22 days.ParticipantsThirty-three senior national-team endurance athletes (mean age 25.8 ± S.D. 2.8 years, 16 women).MeasurementsDaily measurements of sleep (using a microwave Doppler radar at baseline and altitude), oxygen saturation (SpO2), training load and subjective recovery (at altitude).ResultsAt altitude vs. baseline, sleep duration (P = .036) and light sleep (P < .001) decreased, while deep sleep (P < .001) and respiration rate (P = .020) increased. During the first altitude week vs. baseline, deep sleep increased (P = .001). During the first vs. the second and third altitude weeks, time in bed (P = .005), sleep duration (P = .001), and light sleep (P < .001) decreased. Generally, increased SpO2 was associated with increased deep sleep while increased training load was associated with increased respiration rate.ConclusionThis is the first study to document changes in sleep from near-sea-level baseline and during a training camp at 1800 m in elite endurance athletes. Ascending to altitude reduced total sleep time and light sleep, while deep sleep and respiration rate increased. SpO2 and training load at altitude were associated with these responses. This research informs our understanding of the changes in sleep occurring in elite endurance athletes attending training camps at competition altitudes.
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- Jones, Thomas W., et al.
(författare)
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Anthropometric, Physiological, and Performance Developments in Cross-country Skiers
- 2021
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Ingår i: Medicine & Science in Sports & Exercise. - : American collegeof sports medicine. - 0195-9131 .- 1530-0315. ; 53:12, s. 2553-2564
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Tidskriftsartikel (refereegranskat)abstract
- Purpose This study aimed to describe changes in laboratory-assessed anthropometric and physiological characteristics, training volumes, and competitive performance in national development-team cross-country skiers over a 25-month period, and to analyze whether changes in competitive performance could be predicted by changes in laboratory-assessed qualities and training volumes.Methods Data collected over 25 months from 30 national development-team cross-country skiers (14 women, 16 men; age, 18–23 yr) were analyzed retrospectively using multivariate statistics. Anthropometric and physiological characteristics were assessed via dual-energy x-ray absorptiometry and incremental roller-ski treadmill tests, respectively. Total training volumes and distributions of low- and high-intensity training were analyzed from online training diaries, and competitive performance was determined by International Ski Federation (FIS) distance and sprint points.Results Whole- and upper-body lean mass increased in the full cohort of skiers (n = 30; both P < 0.05), whereas lower-body lean mass, whole-body fat mass, speed and oxygen uptake (V˙O2) at a blood lactate concentration (BLa) of 2 and 4 mmol·L−1, as well as time-trial completion time, power output, and peak V˙O2, improved in the women only (all P < 0.05). Valid predictive models were identified for female skiers’ best FIS distance points (R2 = 0.81/Q2 = 0.51) and changes in FIS distance points (R2 = 0.83/Q2 = 0.54), with body mass, fat mass, lean mass, V˙O2peak, and speed at a BLa of 4 mmol·L−1 identified as consistently important variables for projection.Conclusions The valid prediction of competitive performance was achieved for women only in distance events. This study suggests that improvements in body composition and aerobic capacity may be more beneficial for elite female development-level skiers than for their male counterparts. These results have implications for athlete selection and performance development.
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- Karlsson, Øyvind, 1989-, et al.
(författare)
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391 A comparison of the prevalence and severity of health problems in national team cross-country skiers over a competitive season
- 2021
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Konferensbidrag (refereegranskat)abstract
- Background A limited number of long-term prospective studies have investigated health problems in competitive cross-country skiers. Moreover, limited information exists regarding differences in the prevalence and severity of health problems between senior and development female and male cross-country skiers.Objective To compare the prevalence and severity of health problems between senior and development female and male national team cross-country skiers.Design Comparative, prospective, observational cohort study.Setting Senior and development national cross-country ski teams.Participants Eighteen (9 women, 9 men) senior and 22 (9 women, 13 men) development national team skiers.Intervention Skiers self-reported their health problems weekly for 17 weeks throughout the 2019/2020 competitive cross-country ski season using the Oslo Sports Trauma Research Center Questionnaire on Health Problems (OSTRC-H2).Main Outcome Measurements We calculated weekly prevalence and severity measures for illnesses, acute and overuse injuries, substantial health problems (i.e., health problems leading to moderate or severe reductions in training volume or sports performance, or a complete inability to participate) and all health problems combined.Results Weekly response rate to the OSTRC-H2 was 90% (SD 7%). Average weekly prevalence of substantial (~12%) and all (~25%) health problems were similar between senior and development team skiers. However, illness prevalence was lower in senior vs. development skiers (8%, 95% CI [3%, 13%] vs. 13%, 95% CI [9%, 17%], respectively; p = .026) and injuries were higher (12%, 95% CI [9%, 15%] vs. 5%, 95% CI [3%, 7%]; p < .001). There were no differences in severity measures (all p > .05).Conclusions Health problems were relatively common among the skiers, with one quarter affected by at least one problem at any given time. While the prevalence of all health problems was similar, illnesses were less prevalent in the senior compared to the development team skiers and injuries were more prevalent.
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