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- Carlsson, Magnus, et al.
(author)
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Gross and delta efficiencies during uphill running and cycling among elite triathletes.
- 2020
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In: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 120:5, s. 961-968
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Journal article (peer-reviewed)abstract
- PURPOSE: To investigate the gross efficiency (GE) and delta efficiency (DE) during cycling and running in elite triathletes.METHODS: Five male and five female elite triathletes completed two incremental treadmill tests with an inclination of 2.5° to determine their GE and DE during cycling and running. The speed increments between the 5-min stages were 2.4 and 0.6 km h-1 during the cycling and running tests, respectively. For each test, GE was calculated as the ratio between the mechanical work rate (MWR) and the metabolic rate (MR) at an intensity corresponding to a net increase in blood-lactate concentration of 1 mmol l-1. DE was calculated by dividing the delta increase in MWR by the delta increase in MR for each test. Pearson correlations and paired-sample t tests were used to investigate the relationships and differences, respectively.RESULTS: There was a correlation between GEcycle and GErun (r = 0.66; P = 0.038; R2 = 0.44), but the correlation between DEcycle and DErun was not statistically significant (r = - 0.045; P = 0.90; R2 = 0.0020). There were differences between GEcycle and GErun (t = 80.8; P < 0.001) as well as between DEcycle and DErun (t = 27.8; P < 0.001).CONCLUSIONS: Elite triathletes with high GE during running also have high GE during cycling, when exercising at a treadmill inclination of 2.5°. For a moderate uphill incline, elite triathletes are more energy efficient during cycling than during running, independent of work rate.
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| 3. |
- Carlsson, Tomas, et al.
(author)
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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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In: Frontiers in Sports and Active Living. - : Frontiers Media SA. - 2624-9367. ; 4
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Journal article (peer-reviewed)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.
(author)
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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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In: ERJ Open Research. - : European Respiratory Society (ERS). - 2312-0541. ; 7:1
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Journal article (peer-reviewed)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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| 6. |
- Högman, Marieann, et al.
(author)
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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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In: European Respiratory Journal. - : European Respiratory Society. - 0903-1936 .- 1399-3003. ; 56:suppl 64
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Journal article (peer-reviewed)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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| 8. |
- Kanagarajan, Selvaraju, et al.
(author)
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Production of functional human fetal hemoglobin in Nicotiana benthamiana for development of hemoglobin-based oxygen carriers
- 2021
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In: International Journal of Biological Macromolecules. - : Elsevier BV. - 0141-8130 .- 1879-0003. ; 184, s. 955-966
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Journal article (peer-reviewed)abstract
- Hemoglobin-based oxygen carriers have long been pursued to meet clinical needs by using native hemoglobin (Hb) from human or animal blood, or recombinantly produced Hb, but the development has been impeded by safety and toxicity issues. Herewith we report the successful production of human fetal hemoglobin (HbF) in Nicotiana benthamiana through Agrobacterium tumefaciens-mediated transient expression. HbF is a heterotetrameric protein composed of two identical α- and two identical γ-subunits, held together by hydrophobic interactions, hydrogen bonds, and salt bridges. In our study, the α- and γ-subunits of HbF were fused in order to stabilize the α-subunits and facilitate balanced expression of α- and γ-subunits in N. benthamiana. Efficient extraction and purification methods enabled production of the recombinantly fused endotoxin-free HbF (rfHbF) in high quantity and quality. The transiently expressed rfHbF protein was identified by SDS-PAGE, Western blot and liquid chromatography-tandem mass spectrometry analyses. The purified rfHbF possessed structural and functional properties similar to native HbF, which were confirmed by biophysical, biochemical, and in vivo animal studies. The results demonstrate a high potential of plant expression systems in producing Hb products for use as blood substitutes.
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