| 1. |
- Ainegren, Mats, 1963-, et al.
(författare)
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Effects of Aerodynamic Drag and Drafting on Propulsive Force and Oxygen Consumption in Double Poling Cross-Country Skiing
- 2022
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Ingår i: Medicine & Science in Sports & Exercise. - 0195-9131 .- 1530-0315. ; 54:7, s. 1058-1065
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Tidskriftsartikel (refereegranskat)abstract
- Purpose This study aimed to investigate the effects of aerodynamic drag and drafting on propulsive force (FPROP), drag area (CDA), oxygen cost (V˙O2), metabolic rate (Ė), and heart rate (HR) during roller skiing on a treadmill in a wind tunnel using the double poling technique. A secondary aim was to investigate the effects of wind versus no-wind test conditions on the same physiological parameters. Methods Ten subjects of each gender participated in the experiments. One pair of skiers of the same gender roller skied simultaneously in line with the air flow; the distance between the skiers was 2.05 m. Each pair was tested as follows: I) with wind, leading; II) with wind, drafting; and III) without wind. The treadmill inclination was 0° throughout the tests. For the wind conditions, the air velocity was similar to the treadmill belt speed: 3 to 7 m·s-1 for men and 3 to 6 m·s-1 for women. Results Drafting resulted in significantly (P < 0.05) lower FPROP,CDA, V˙O2, and Ė, compared with leading, for both genders at racing speed but not at lower speeds, whereas HR was only affected for the male skiers at racing speed. The test without wind resulted in significantly lower FPROP, V˙O2, and Ė at all tested speeds compared with the tests with wind present, whereas HR was lower only at higher speeds. Conclusions At racing speed, but not at lower speeds, the positive effects of drafting behind a skier during double poling were obvious and resulted in a lower FPROP, CDA, V˙O2, Ė, and HR. Tests without wind present put even lower demands on the skiers' physiology, which was also evident at lower speeds.
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| 2. |
- Canclini, A., et al.
(författare)
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HISTORICAL ANALYSIS OF DOUBLE POLING IN HIGH-LEVEL CROSS COUNTRY SKIING (XCS)
- 2020
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Ingår i: Karczewska-Lindinger, M., Hakkarainen, A., Linnamo, V., Lindinger, S. (2020) (Eds), Science and Skiing VIII, University of Jyväskylä (publisher), Jyväskylä, Finland, ISBN 978-951-39-8077-1, pp 202. - Jyväskylä, Finland : University of Jyväskylä. - 9789513980771
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Bokkapitel (refereegranskat)
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| 3. |
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| 5. |
- Holmberg, Hans-Christer, et al.
(författare)
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Contribution of the legs to double-poling performance in elite cross-country skiers.
- 2006
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Ingår i: Medicine and science in sports and exercise. - : Ovid Technologies (Wolters Kluwer Health). - 0195-9131 .- 1530-0315. ; 38:10, s. 1853-60
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Tidskriftsartikel (refereegranskat)abstract
- In the classical style of cross-country skiing, the double-poling (DP) technique, which is regarded as an upper-body exercise, is used on the flatter parts of a course. Limited biomechanical and physiological data are available about DP compared with other cross-country skiing techniques. The purpose of the present study was to evaluate the possible role of the lower body during DP.Eleven elite cross-country skiers performed two incremental tests using DP roller skiing at 1 degree inclination on a treadmill with or without locking the knee and ankle joints (DPLOCKED and DPFREE). Maximal and peak oxygen uptake (VO2max and VO2peak) during classic diagonal skiing and DP, respectively, were measured. In addition, heart rate, blood lactate concentration, and maximal DP velocity (Vmax) were determined. Pole-ground reaction forces and joint angles (elbow, hip, knee, and ankle) were analyzed.The skiers obtained 7.7% higher VO2peak, 9.4% higher Vmax, and 11.7% longer time to exhaustion during DPFREE compared with DPLOCKED (all P < 0.05). There was a higher heart rate and blood lactate concentration in DPLOCKED at submaximal stages (all P < 0.05), with no difference in oxygen consumption. At 85% Vmax, corresponding to approximately 81% VO2peak FREE, the differences in physiological variables were accompanied by a 13.6% higher poling frequency, a 4.9% shorter poling phase, 13.3% shorter recovery phase, and 10.9% lower relative pole force in DPLOCKED (all P < 0.05).Movements of the knee and ankle joints are an integrative part in the skillful use of the DP technique, and restriction of the motion in these joints markedly affects both biomechanical and physiological variables, impairing DP performance.
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| 6. |
- Karczewska-Lindinger, Magdalena, et al.
(författare)
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Force Generation Profiles of Para-Nordic Sit-Skiers Representing Different Physical Impairments
- 2021
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Ingår i: Journal of Science in Sport and Exercise. - : Springer Science and Business Media LLC. - 2662-1371 .- 2096-6709. ; 3, s. 281-291
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Tidskriftsartikel (refereegranskat)abstract
- PurposeTo biomechanically profile force generation connected to the complex role of the trunk in double poling in a representative sample of Para-Nordic sit-skiers.MethodsTwelve male World Cup Para-Nordic sit-skiers (sport classes: LW10–12) were skiing on flat snow terrain at submaximal speed of 4.5 m/s (~ 73% maximum speed). 2D video (50 Hz) and pole force analyses (1000 Hz) were performed synchronously, examining angle, force and cycle characteristics to analyse the role of the trunk in generating propulsion.ResultsLW10–11.5 skiers lost between 21% and 4% propulsive force versus LW12 athletes only due to different geometrics of the trunk and pole angle at an equal axial pole force. While LW10–11 skiers indicated trunk extension or position maintenance during pole thrust, LW11.5–12 skiers showed strong trunk flexion combined with smaller pole angles to the ground. Hence, LW11.5–12 skiers could create larger propulsive forces and therefore greater cycle lengths at lower cycle rates at the same speed. Maximum speed increased from LW10 to LW12 and was significantly correlated to trunk flexion range of motion (r = 0.63) and cycle length (r = 0.59). Trunk flexion ROM showed a significant relationship to the impulse of propulsive force (r = 0.63) and pole angle to the ground (r = − 0.76) (all P < 0.05).ConclusionThe impact of impairment on the force production profiles and its physiological-biomechanical consequences need further investigation also in other terrains and at wider spectrums of skiing speeds. The evident problem of low numbers of LW10–11 skiers in World Cup needs creative future solutions for research.
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| 7. |
- Karczewska-Lindinger, Magdalena, 1986, et al.
(författare)
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Race and split time analysis in para nordic sit-skiing
- 2019
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Ingår i: 8th International Congress on Science and Skiing (ICSS) - Abstract book. Vuokatti, Finland, March 11th - 15th, 2019, s. 69. - 9789513976835
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Konferensbidrag (refereegranskat)
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| 8. |
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| 9. |
- Kuylenstierna, D., et al.
(författare)
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VALIDATION, ACCURACY AND PRACTICAL USE OF A POWER MEASUREMENT SYSTEM FOR CROSS-COUNTRY SKIING ANALYSIS – A PILOT STUDY
- 2020
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Ingår i: Karczewska-Lindinger, M., Hakkarainen, A., Linnamo, V., Lindinger, S. (2020) (Eds), Science and Skiing VIII, University of Jyväskylä. - Jyväskylä, Finland : University of Jyväskylä. - 9789513980771 ; , s. 154-161
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Bokkapitel (refereegranskat)
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