| 1. |
- Ainegren, Mats, 1963-, et al.
(författare)
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Roller ski rolling resistance and its effects on elite athletes’ performance
- 2009
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Ingår i: Sports Engineering. - Paris : Springer. - 1369-7072 .- 1460-2687. - 9782287990564 - 9782287990557 ; 11:3, s. 143-157
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Tidskriftsartikel (refereegranskat)abstract
- Modern ski-treadmills allow cross-country skiers, biathletes and ski-orienteers to test their physical fitness in a laboratory environment whilst performing classical and freestyle (skating) techniques on roller skis. For elite athletes, the differences in performance between test occasions are quite small, thus emphasising the importance of knowing the roller skis’ rolling resistance in order to allow the correct comparison between the results of different test occasions. In this study, the roller skis’ rolling resistance was measured on the ski-treadmill’s surface using a roller ski rolling resistance measurement system specially produced for this purpose. The study investigated the influence of significant changes in rolling resistance on physiological variables. The results showed that during submaximal exercise, power, oxygen uptake, heart rate and blood lactate were significantly changed by different rolling resistances, while there were no significant or only small changes to cycle rate, cycle length and ratings of perceived exertion. Incremental maximal tests showed that time to exhaustion was significantly changed by different rolling resistances and this occurred without significant changes in maximal power, maximal oxygen uptake, maximal heart rate and blood lactate, and that the influence on ratings of perceived exertion were insignificant or small.
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| 2. |
- Ainegren, Mats, 1963-, et al.
(författare)
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Rolling resistance for treadmill roller skiing
- 2008
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Ingår i: Sports Engineering. - : Springer. - 1369-7072 .- 1460-2687. ; 11:1, s. 23-29
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Tidskriftsartikel (refereegranskat)abstract
- Modern treadmills allow cross-country skiers, biathletes and ski-orienteers to test their physical performance under laboratory conditions using classical and freestyle techniques on roller skis. The differences in performance between tests are quite small for elite athletes, and it is therefore of great importance to control the rolling resistance of the roller skis. Otherwise different physiological tests cannot be accurately compared.This study shows that during a warm-up period of 30 minutes the coefficient of rolling resistance (µR) decreases to about 60-65% and 70-75% of its initial value for freestyle and classical roller skis respectively.Simultaneous measurements of temperature and µR shows that stabilized rolling resistance corresponds to a certain running temperature for a given normal force on the roller ski.Tests were also performed on the influence on µR of normal force, velocity and inclination. Normal forces produced significant influence on µR , while different velocities and inclinations of the treadmill only resulted in small changes in µR.
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| 3. |
- Gilenstam, Kajsa, 1974-, et al.
(författare)
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Influence of stick stiffness and puck weight on puck velocity during slap shots in women's ice hockey
- 2009
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Ingår i: Sports Engineering. - : Springer Science and Business Media LLC. - 1369-7072 .- 1460-2687. ; 11:3, s. 103-107
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies have found that reduced stick stiffness increases puck velocity in young male ice hockey players. This study investigates the hypothesis that female players are disadvantaged by using equipment that is designed for taller and stronger players. The purpose of this study was to investigate if stick flexibility and puck weight affect puck velocity in standing slap shots performed by female ice hockey players. There was a significant increase in puck velocity (4.1% p=0.037) when stick stiffness and puck weight were reduced. ANOVA revealed that there was a significant correlation between stick, puck and the participant herself (R2=0.987). Spearman’s correlation analysis revealed that participants with higher puck velocities benefitted the most when the stick flexibility and puck weight were reduced (r=0.648; p=0.043). It was concluded that decreased stick stiffness and puck weight increased puck velocity in standing slap shots for female ice hockey players.
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| 4. |
- Gullstrand, Lennart, et al.
(författare)
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A new method for recording the temporal pattern of stride during treadmill running
- 2009
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Ingår i: Sports Engineering. - : Springer Science and Business Media LLC. - 1369-7072 .- 1460-2687. ; :11, s. 195-200
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the reliability of a new infrared light based method (IR40) for recording temporal stride patterns during treadmill running. The IR40 device, emitting a tight web of 40 infrared light beams 10 mm above the treadmill running surface, was compared to a previously validated electro-pneumatic contact shoe (CS) method while nine well-trained athletes ran at 2.8, 3.3, 3.9, 4.4, 5.0, and 5.6 m s−1. Disconnection and reconnection of the IR beams marked the stance phase. The sampling rate was 500 Hz for both methods. The stance phase duration was on average 11.5 (±8.4) ms longer with the IR40 than with the CS depending on earlier touch down (8.3 ± 6.2 ms) and delayed toe off (3.2 ± 5.3 ms) registrations. Significantly different stance phases were recorded between all velocities and for both methods. Thus, despite the fact that the IR40 systematically measured a somewhat longer stance phase duration than CS, the IR40 is nonetheless useful for temporal stride analysis during treadmill running.
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| 5. |
- Kuzmin, Leonid, et al.
(författare)
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Dirt absorption on the ski running surface - quantification and influence on the gliding ability
- 2006
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Ingår i: Sports Engineering. - 1369-7072 .- 1460-2687. ; 9:3, s. 137-146
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Tidskriftsartikel (refereegranskat)abstract
- We propose a thesis that minimizing dirt on the running surface of skis improves the surface glide. Waxing usually improves the gliding ability of skis in the short term. But how does waxing affect pollution absorption in the long term? In this study a number of skis with a transparent base and a white background were treated by steel scraping and with different glide waxes. The gliding ability of waxed and unwaxed skis, the sliding surface whiteness and the hydrophobicity were tested and documented. Tests were performed before and after the skis had been used for different distances. It was observed that all the waxed skis (regardless of the wax used) absorbed more dirt than unwaxed and as result all waxed skis lose their glide ability sooner then unwaxed (fresh scraped) skis on wet snow conditions.
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