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- 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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| 2. |
- Lajunen, Kimmo, et al.
(författare)
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Effect of Sitting Posture on Sit-Skiing Economy in Non-disabled Athletes.
- 2020
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Ingår i: Frontiers in sports and active living. - : Frontiers Media SA. - 2624-9367. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- This study focused on resolving the differences in economy between two common sit-skiing postures used by disabled athletes, suspected to be the most and least effective. Ten experienced non-disabled male cross-country skiers went through an incremental testing protocol with an ergometer simulating double poling in two sitting postures "kneeing" and "knee-high." The protocol consisted of 3 × 4 min steady-state stages (13, 22, and 34% of maximal sprint power output). Subjects' respiratory gases and heart rate were measured and blood lactate concentrations were determined. In addition, pulling forces and motion capture recordings were collected. Oxygen consumption was 15.5% (p < 0.01) higher with "knee-high" compared to "kneeing" at stage three. At stage three cycle rate was 13.8% higher (p < 0.01) and impulse of force 13.0% (p < 0.05) and hip range of motion 46.6% lower (p < 0.01) with "knee-high" compared to "kneeing." "Kneeing" was found to be considerably more economical than "knee-high" especially at 34% of maximum sprint power output. This might have been due to higher cycle rate, lower impulse of force and smaller hip range of motion with "knee-high" compared to "kneeing." This indicates that sit-skiers should adopt, if possible, posture more resembling the "kneeing" than the "knee-high" posture. Combining such physiological and biomechanical measurements and to further develop them to integrated miniature wearable sensors could offer new possibilities for training and testing both in the laboratory and in the field conditions.
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| 3. |
- Lindinger, Stefan J, et al.
(författare)
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Changes in upper body muscle activity with increasing double poling velocities in elite cross-country skiing
- 2009
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 106:3, s. 353-363
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate whether the stretch-shortening cycle (SSC) contraction is integrated in neuromuscular activation in upper body muscles during double poling in cross-country skiing. Thirteen elite skiers performed double poling roller-skiing at increasing treadmill velocities of 9, 15, 21, 27 km h(-1) and their individual maximal velocity. Elbow angle, axial pole force and surface EMG in the triceps brachii, pectoralis major, latissimus dorsi and teres major muscle were recorded. Increases in peak pole force, rate of force development and elbow flexion angular velocities were identified (P < 0.05). The mean MVC-normalized EMG amplitudes increased during the pre-activation phase before pole plant, elbow flexion and the reflex-mediated phase between 30 and 120 ms after pole plant due to velocity increases (P < 0.05). It is thus suggested that elite cross-country skiers use SSC during double poling, particularly in the triceps muscle in order to generate high forces.
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| 5. |
- Rapp [Nordin], Erika, et al.
(författare)
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Preference for full-fat over low-fat foods among individuals suffering from coronary heart disease and healthy controls
- 2009
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Ingår i: Physiology and Behavior. - : Elsevier. - 0031-9384 .- 1873-507X. ; 98:4, s. 489-497
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Tidskriftsartikel (refereegranskat)abstract
- Dietary behaviour can modify the risks for coronary heart disease (CHD). Dietary fat contributes to the sensory characteristics of many foods, but there are individual differences in liking for regular and reduced fat products. Preference for dietary fat might differ between healthy individuals and those of diagnosed CHD status. Preference for full-fat versus low-fat foods was assessed in a group suffering from CHD (N = 24) and a healthy control group (N = 41). Preferences were evaluated using a series of paired preference tests including 34 food pairs. Further, patterns across fat preference and a range of known risk factors for CHD were examined. The study was conducted in Sweden; March 2004 until May 2006. Overall the full-fat food items were preferred to the low-fat alternatives by both patients and control participants. The pattern of preference responses diverged significantly between patients and controls on only four of the 34 food items, in both directions, why preference related to total fat content per se is not confirmed as differentiating significantly between a group diagnosed with CHD compared to a healthy control group.
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