| 1. |
- Carlsson, Magnus, et al.
(författare)
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Physiological demands of competitive sprint and distance performance in elite female cross-country skiing
- 2016
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Ingår i: Journal of Strength and Conditioning Research. - : Lippincott Williams & Wilkins. - 1064-8011 .- 1533-4287. ; 30:8, s. 2138-2144
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Tidskriftsartikel (refereegranskat)abstract
- The purpose was to investigate the relationship between elite females' competitive performance capability in sprint and distance cross-country skiing and the variables of gross efficiency (GE), work rate at the onset of blood-lactate accumulation (OBLA4mmol), maximal oxygen uptake (V[Combining Dot Above]O2max), maximal speed (Vmax), and peak upper-body oxygen uptake (V[Combining Dot Above]O2peak). Ten elite female cross-country skiers (age 24.5 ± 2.8 years) completed treadmill roller-skiing tests to determine GE, OBLA4mmol, and V[Combining Dot Above]O2max using the diagonal-stride technique as well as Vmax and V[Combining Dot Above]O2peak using the double-poling technique. International Ski Federations ranking points for sprint (FISsprint) and distance (FISdist) races were used as competitive performance data. There were correlations between the FISsprint and the V[Combining Dot Above]O2max expressed absolutely (p = 0.0040), Vmax (p = 0.012), and V[Combining Dot Above]O2peak expressed absolutely (p < 0.001) and as a simple ratio-standard (p = 0.049). The FISdist were correlated with OBLA4mmol (p = 0.048), V[Combining Dot Above]O2max expressed absolutely (L·min) (p = 0.015) and as a simple ratio-standard (p = 0.046), and V[Combining Dot Above]O2peak expressed absolutely (p = 0.036) and as a simple ratio-standard (ml·min·kg) (p = 0.040). The results demonstrate that the physiological abilities reflected by V[Combining Dot Above]O2max and V[Combining Dot Above]O2peak are indicators of competitive sprint and distance performance in elite female cross-country skiing. In addition, the ability to generate a high Vmax indicates the performance in sprint races, whereas the skier's OBLA4mmol reflects the performance capability in distance races. Based on the results, when evaluating the performance capacity of elite female cross-country skiers, it is recommended to use physiological variables that reflect competitive performance.
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| 2. |
- Carlsson, Tomas, et al.
(författare)
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The effects of strength training versus ski-ergometer training on double-poling capacity of elite junior cross-country skiers
- 2017
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 117:8, s. 1523-1532
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Tidskriftsartikel (refereegranskat)abstract
- PurposeTo compare the effects of strength training versus ski-ergometer training on double-poling gross efficiency (GE), maximal speed (Vmax), peak oxygen uptake (V˙O2peak" role="presentation" style="box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">V˙O2peakV˙O2peak) for elite male and female junior cross-country skiers.MethodsThirty-three elite junior cross-country skiers completed a 6-week training-intervention period with two additional 40-min training sessions per week. The participants were matched in pairs and within each pair randomly assigned to either a strength-training group (STR) or a ski-ergometer-training group (ERG). Before and after the intervention, the participants completed three treadmill roller-skiing tests to determine GE, Vmax, and V˙O2peak" role="presentation" style="box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">V˙O2peakV˙O2peak. Mixed between-within subjects analysis of variance (ANOVA) was conducted to evaluate differences between and within groups. Paired samples t tests were used as post hoc tests to investigate within-group differences.ResultsBoth groups improved their Vmax and V˙O2peak" role="presentation" style="box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">V˙O2peakV˙O2peak expressed absolutely (all P < 0.01). For the gender-specific sub-groups, it was found that the female skiers in both groups improved both Vmax and V˙O2peak" role="presentation" style="box-sizing: border-box; display: inline-table; line-height: normal; letter-spacing: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">V˙O2peakV˙O2peak expressed absolutely (all P < 0.05), whereas the only within-group differences found for the men were improvements of Vmax in the STR group. No between-group differences were found for any of the investigated variables.ConclusionsPhysiological and performance-related variables of importance for skiers were improved for both training regimes. The results demonstrate that the female skiers’ physiological adaptations to training, in general, were greater than those of the men. The magnitude of the physiological adaptations was similar for both training regimes.
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| 3. |
- Carlsson, Tomas, et al.
(författare)
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The Modern Double-Poling Technique Is Not More Energy Efficient Than the Old-Fashioned Double-Poling Technique at a Submaximal Work Intensity
- 2022
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Ingår i: Frontiers in Sports and Active Living. - : Frontiers Media SA. - 2624-9367. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the study was to investigate whether there are energy-efficiency differences between the execution of the old-fashioned double-poling technique (DPOLD) and the modern double-poling technique (DPMOD) at a submaximal work intensity among elite male cross-country skiers. Fifteen elite male cross-country skiers completed two 4-min tests at a constant mechanical work rate (MWR) using the DPMOD and DPOLD. During the last minute of each test, the mean oxygen uptake (VO2) and respiratory exchange ratio (RER) were analyzed, from which the metabolic rate (MR) and gross efficiency (GE) were calculated. In addition, the difference between pretest and posttest blood-lactate concentrations (BLadiff) was determined. For each technique, skiers’ joint angles (i.e., heel, ankle, knee, hip, shoulder, and elbow) were analyzed at the highest and lowest positions during the double-poling cycle. Paired-samples t-tests were used to investigate differences between DPMOD and DPOLD outcomes. There were no significant differences in either VO2mean, MR, GE, or BLadiff (all P > 0.05) between the DPMOD and DPOLD tests. DPMOD execution was associated with a higher RER (P < 0.05). Significant technique-specific differences were found in either the highest and/or the lowest position for all six analyzed joint angles (all P < 0.001). Hence, despite decades of double-poling technique development, which is reflected in the significant biomechanical differences between DPOLD and DPMOD execution, at submaximal work intensity, the modern technique is not more energy efficient than the old-fashioned technique.
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| 4. |
- Högman, Marieann, et al.
(författare)
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Differences in nitric oxide airway diffusion after maximum oxygen uptake test in asthmatic and nonasthmatic elite junior cross-country skiers
- 2021
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Ingår i: ERJ Open Research. - : European Respiratory Society (ERS). - 2312-0541. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Asthma is common in cross-country skiers and is often treated with ß2-agonists and inhaled corticosteroids (ICS). Exhaled nitric oxide is often used to guide ICS treatment in asthma. This study investigated the change in the pulmonary NO dynamics before and after a maximum oxygen uptake (V̇O2-max) test.An extended NO analysis was performed among Swedish elite junior cross-country skiers (n=25), with and without declared asthma, before and after a V̇O2-max test using roller skis. Asthma was declared by six boys and two girls among whom five occasionally used ICS.There were no differences in the baseline NO parameters between those with and without declared asthma. The diffusion capacity over airway wall (DawNO) was 21 (17,25) mL·s−1 (median, quartiles), which is much increased for this age group. After the V̇O2-max test, there were statistically significant differences from the baseline fraction of exhaled nitric oxide (FENO50), NO-flux from airways, DawNO and alveolar NO values; but not in the NO content in airway wall (CawNO) for all subjects together as one group. However, in the asthma group, differences were only seen in the FENO50 and in CawNO.Interestingly, a majority of the subjects had an increase in the DawNO. An increase in DawNO has been found with allergic asthma together with elevated CawNO. The skiers did not have elevated CawNO, which indicates an absence of inflammation in the airway wall. Modelling of lung NO production clearly shows that the asthma among our skiers is distinct from the allergic asthma in non-athletes.
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| 5. |
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| 6. |
- Högman, Marieann, et al.
(författare)
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Skiers with or without asthma have increased airway diffusion rate of NO from the airways : Konferensbidrag, Muntlig presentation med publicerat abstract (Refereegranskat)
- 2020
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Ingår i: European Respiratory Journal. - : European Respiratory Society. - 0903-1936 .- 1399-3003. ; 56:suppl 64
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Tidskriftsartikel (refereegranskat)abstract
- Exercise induced bronchoconstriction (EIB) is common in skiers and often treated with β2-agonists and inhaled corticosteroids (ICS). We examined 25 elite junior cross-country skiers (17 boys and 8 girls, age 18±1 y) pre and post a V̇O2max test to see how NO parameters of the lung changed. A health declaration was filled in and 6 boys and 2 girls declared that they had asthma diagnosed by a physician, whereas 5 of them were on ICS treatment. NO analysis was done with multiple flows (Högman-Meriläinen algorithm) before and within 10 min after the V̇O2max test. FENO50 was at rest 17 (11, 24) ppb (median, quartiles). CANO was 1.5 (1.1, 1.9) ppb, JawNO 0.75 (0.56, 1.55) nL/s, and CawNO 51 (26, 63) ppb. DawNO was 21 (17,25) mL/s, with only three skiers with values in the range of upper and lower quartiles for reference values. There were no differences in NO parameters between those declaring or not declaring asthma. After the V̇O2max test FENO50 decreased by 5 (3, 8) ppb (p<0.001), JawNO with 0.27 (0.15, 0.49) nL/s (p<0.001), CawNO with 6 (-14, 20) ppb (ns), DawNO with 4 (-3, 14) mL/s (p=0.032), while CANO increased by 0.6 (0.1, 1.2) ppb (p=0.006). Interestingly, the majority of participants had an increase in DawNO. An increase in DawNO has been found in allergic asthma together with elevated CawNO. The skiers did not have elevated CawNO, which indicate an absence of inflammation in the airway wall. Should they withhold ICS, since it does not affect DawNO? Modelling of lung NO production clearly shows that the EIB is distinct from allergic asthma.CANO=alveolar NO, JawNO=NO-flux from airways, CawNO=NO content in airway wall, DawNO=diffusion capacity over airway wall
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| 10. |
- Xuan, Xing, et al.
(författare)
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A Wearable Biosensor for Sweat Lactate as a Proxy for Sport Performance Monitoring
- 2022
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Ingår i: Analysis & Sensing. - : Wiley-VCH Verlagsgesellschaft. - 2629-2742. ; 3:4
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Tidskriftsartikel (refereegranskat)abstract
- In the last decade, sport performance assessment has significantly transformed due to the appearance of disruptive technologies. Subjective pen and paper notations have evolved into advanced wearable sensing systems that acquire performance-related data. The selection of adequate performance metric variables always causes a debate in sport physiology, and this becomes more relevant once new biochemical indicators are proposed, such as sweat lactate. Here, we analyze the correlation of real-time sweat lactate, obtained with a validated wearable biosensor, with the typical physiological parameters often recorded in sports laboratories (e. g., blood lactate, Borg scale for the rating of perceived exertion, heart rate, power output, blood glucose, and respiratory quotient). We found that the heart rate, power output, Borg scale, and blood lactate relate to sweat lactate in independent individuals during cycling activity. Hence, we demonstrate the potential to associate non-invasive, quantitative, and personalized analysis with sport practice.
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| 11. |
- Xuan, Xing, et al.
(författare)
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A Wearable Biosensor for Sweat Lactate as a Proxy for Sport Performance Monitoring
- 2023
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Ingår i: Analysis & Sensing. - : Wiley. - 2629-2742. ; 3:4
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Invited for this month ' s cover are the collaborating groups of Prof. Cuartero and Prof. Crespo at KTH and UCAM universities with the participation of Dalarna University. The cover picture shows a wearable biosensor for the digitalization of lactate in sweat during sport activity. The biosensor is integrated into a microfluidic system for continue lactate monitoring, producing reliable real-time profiles. It was found out that real-time sweat lactate assessment is a potential proxy of personalized training strategies in sports such as cycling." More information can be found in the Research Article by Maria Cuartero, GastonA. Crespo, and co-workers.
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| 12. |
- Xuan, Xing, et al.
(författare)
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Fully Integrated Wearable Device for Continuous Sweat Lactate Monitoring in Sports.
- 2023
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Ingår i: ACS Sensors. - : American Chemical Society (ACS). - 2379-3694. ; 8:6, s. 2401-2409
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Tidskriftsartikel (refereegranskat)abstract
- The chemical digitalization of sweat using wearable sensing interfaces is an attractive alternative to traditional blood-based protocols in sports. Although sweat lactate has been claimed to be a relevant biomarker in sports, an analytically validated wearable system to prove that has not yet been developed. We present a fully integrated sweat lactate sensing system applicable to in situ perspiration analysis. The device can be conveniently worn in the skin to monitor real-time sweat lactate during sports, such as cycling and kayaking. The novelty of the system is threefold: advanced microfluidics design for sweat collection and analysis, an analytically validated lactate biosensor based on a rational design of an outer diffusion-limiting membrane, and an integrated circuit for signal processing with a custom smartphone application. The sensor covering the range expected for lactate in sweat (1-20 mM), with appropriate sensitivity (-12.5 ± 0.53 nA mM-1), shows an acceptable response time (<90 s), and the influence of changes in pH, temperature, and flow rate are neglectable. Also, the sensor is analytically suitable with regard to reversibility, resilience, and reproducibility. The sensing device is validated through a relatively high number of on-body tests performed with elite athletes cycling and kayaking in controlled environments. Correlation outcomes between sweat lactate and other physiological indicators typically accessible in sports laboratories (blood lactate, perceived exhaustion, heart rate, blood glucose, respiratory quotient) are also presented and discussed in relation to the sport performance monitoring capability of continuous sweat lactate.
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