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Ski Simulator

Marie Lund Ohlsson, Jonas Danvind, L Joakim Holmberg
Overuse injuries in the shoulders and lower back are hypothesized to be common in cross-country sit-skiing. Athletes with reduced trunk muscle control mainly sits with their knees higher than hips (KH). To reduce spinal flexion, a position with the knees below the hips (KL) was enabled for these athletes using a frontal trunk support. The aim of the study was to compare the shoulder joint (glenohumeral joint) and L4-L5 joint reactions between the sitting positions KL and KH. Five able-bodied female athletes performed submaximal and maximal exercise tests in the sitting positions KL and KH on a ski-ergometer...
April 13, 2018: Journal of Applied Biomechanics
Simo Ihalainen, Marko S Laaksonen, Sami Kuitunen, Antti Leppävuori, Jussi Mikkola, Stefan Josef Lindinger, Vesa Linnamo
The aim of this study was to identify performance-determining factors in biathlon standing shooting in rest and after intense exercise. Eight Finnish national- and nine junior-team biathletes participated in the study. Participants fired 40 resting shots (REST) and 2 × 5 competition simulation shots (LOAD) after 5 minutes of roller skiing at 95% of peak heart rate. Hit percentage, aiming point trajectory and postural balance were measured from each shot. Cleanness of triggering (ATV, movement of the aiming point 0-0...
February 15, 2018: Scandinavian Journal of Medicine & Science in Sports
A Dutt-Mazumder, K M Newell
The experiment investigated the progressions of the qualitative and quantitative changes in the movement dynamics of learning the ski-simulator as a function of prior-related task experience. The focus was the differential timescales of change in the candidate collective variable, neuromuscular synergies, joint motions, and task outcome as a function of learning over 7 days of practice. Half of the novice participants revealed in day 1 a transition of in-phase to anti-phase coupling of center of mass (CoM)-platform motion whereas the remaining novices and experienced group all produced on the first trial an anti-phase CoM-platform coupling...
May 2018: Scandinavian Journal of Medicine & Science in Sports
Jijian Lian, Xiaoqun Wang, Wenjiao Zhang, Bin Ma, Dongming Liu
As excess water is discharged from a high dam, low frequency noise (air pulsation lower than 10 Hz, LFN) is generated and propagated in the surrounding areas, causing environmental hazards such as the vibration of windows and doors and the discomfort of local residents. To study the generation mechanisms and key influencing factors of LFN induced by flood discharge and energy dissipation from a high dam with a ski-jump type spillway, detailed prototype observations and analyses of LFN are carried out. The discharge flow field is simulated and analyzed using a gas-liquid turbulent flow model...
November 30, 2017: International Journal of Environmental Research and Public Health
Cong Liu, Xujun Wang, Georgi Z Genchev, Hui Lu
MOTIVATION: New developments in high-throughput genomic technologies have enabled the measurement of diverse types of omics biomarkers in a cost-efficient and clinically-feasible manner. Developing computational methods and tools for analysis and translation of such genomic data into clinically-relevant information is an ongoing and active area of investigation. For example, several studies have utilized an unsupervised learning framework to cluster patients by integrating omics data...
July 15, 2017: Methods: a Companion to Methods in Enzymology
Jernej Kapus, Igor B Mekjavic, Adam C McDonnell, Anton Ušaj, Janez Vodičar, Peter Najdenov, Miroljub Jakovljević, Polona Jaki Mekjavić, Milan Žvan, Tadej Debevec
We aimed to elucidate potential differential effects of hypoxia on cardiorespiratory responses during submaximal cycling and simulated skiing exercise between adults and pre-pubertal children. Healthy, low-altitude residents (adults, N=13, Age=40±4yrs.; children, N=13, age=8±2yrs.) were tested in normoxia (Nor: PiO2=134±0.4 mmHg; 940 m) and normobaric hypoxia (Hyp: PiO2=105±0.6 mmHg; ~3 000 m) following an overnight hypoxic acclimation (≥12-hrs). On both days, the participants underwent a graded cycling test and a simulated skiing protocol...
July 2017: International Journal of Sports Medicine
Jeffrey R Campbell, Irving S Scher, David Carpenter, Bruce L Jahnke, Randal P Ching
Alpine touring (AT) equipment is designed for ascending mountains and snow skiing down backcountry terrain. Skiers have been observed using AT boots in alpine (not made for Alpine Touring) ski bindings. We tested the effect on the retention-release characteristics of AT boots used in alpine bindings. Ten AT ski boots and 5 alpine ski boots were tested in 8 models of alpine ski bindings using an ASTM F504-05 (2012) apparatus. Thirty-one percent of the AT boots released appropriately when used in alpine ski bindings...
October 1, 2017: Journal of Applied Biomechanics
O Ohtonen, S J Lindinger, C Göpfert, W Rapp, V Linnamo
This study investigated how the fatigue caused by a 20-km simulated skating cross-country skiing race on snow affects the final spurt performance from a biomechanical perspective. Subjects performed a 100-m maximal skiing trial before and at the end of the simulated race. Cycle characteristics, ground reaction forces from skis and poles, and muscle activity from eight muscles were recorded during each trial. Results showed that subjects were in a fatigued state after the simulated race manifested by 11.6% lower skiing speed (P<...
February 2018: Scandinavian Journal of Medicine & Science in Sports
Cong Liu, Jianping Jiang, Jianlei Gu, Zhangsheng Yu, Tao Wang, Hui Lu
BACKGROUND: High-throughput technology could generate thousands to millions biomarker measurements in one experiment. However, results from high throughput analysis are often barely reproducible due to small sample size. Different statistical methods have been proposed to tackle this "small n and large p" scenario, for example different datasets could be pooled or integrated together to provide an effective way to improve reproducibility. However, the raw data is either unavailable or hard to integrate due to different experimental conditions, thus there is an emerging need to develop a method for "knowledge integration" in high-throughput data analysis...
December 23, 2016: BMC Systems Biology
Matteo Anselmino, Stefania Scarsoglio, Andrea Saglietto, Fiorenzo Gaita, Luca Ridolfi
AIMS: Clinical data indicating a heart rate (HR) target during rate control therapy for permanent atrial fibrillation (AF) and assessing its eventual relationship with reduced exercise tolerance are lacking. The present study aims at investigating the impact of resting HR on the hemodynamic response to exercise in permanent AF patients by means of a computational cardiovascular model. METHODS: The AF lumped-parameter model was run to simulate resting (1 Metabolic Equivalent of Task-MET) and various exercise conditions (4 METs: brisk walking; 6 METs: skiing; 8 METs: running), considering different resting HR (70 bpm for the slower resting HR-SHR-simulations, and 100 bpm for the higher resting HR-HHR-simulations)...
2017: PloS One
Huy D Vu, Kazimierz Wie Ski, Steven C Pennings
Ecosystem engineers affect different organisms and processes in multiple ways at different spatial scales. Moreover, similar species may differ in their engineering effects for reasons that are not always clear. We examined the role of four species of burrowing crabs (Sesarma reticulatum, Eurytium limosum, Panopeus herbstii, Uca pugnax) in engineering tidal creek networks in salt marshes experiencing sea level rise. In the field, crab burrows were associated with heads of eroding creeks and the loss of plant (Spartina alterniflora) stems...
January 2017: Ecology
V Rosso, L Gastaldi, W Rapp, S Lindinger, Y Vanlandewijck, V Linnamo
The purpose of this study was to investigate the biomechanics of cross-country sit-skiing in simulated and natural skiing. Thirteen international level athletes participated in a ski ergometer test (simulated conditions) and a test on snow in a ski-tunnel (natural conditions) using their personal sit-ski. Tests in both conditions were performed at individual maximal speed. When comparing the two conditions the main results were: (1) maximal speed in simulated conditions was lower (p<0.05) but correlated well with the natural condition (r=0...
February 2017: Journal of Electromyography and Kinesiology
Keizo Yamamoto, Makoto Tsubokura, Jun Ikeda, Keiji Onishi, Sophie Baleriola
The purpose of this study was to investigate the effects of posture of a ski jumper on aerodynamic characteristics during the take-off using computational fluid dynamics (CFD). The CFD method adopted for this study was based on Large-Eddy Simulation. Body surface data were obtained by 3-D laser scanning of an active ski jumper. Based on video analysis of the actual take-off movement, two sets of motion data were generated (world-class jumper A and less-experienced jumper B). The inlet flow velocity that corresponds to the in-run velocity in actual ski jumping was set to 23...
November 7, 2016: Journal of Biomechanics
Robert Eberle, Dieter Heinrich, Peter Kaps, Michael Oberguggenberger, Werner Nachbauer
A common anterior cruciate ligament (ACL) injury situation in alpine ski racing is landing back-weighted after a jump. Simulated back-weighted landing situations showed higher ACL-injury risk for increasing ski boot rear stiffness (SBRS) without considering muscles. It is well known that muscle forces affect ACL tensile forces during landing. The purpose of this study is to investigate the effect of different SBRS on the maximal ACL tensile forces during injury prone landings considering muscle forces by a two-dimensional musculoskeletal simulation model...
June 2017: Journal of Sports Sciences
Erik Andersson, Hans-Christer Holmberg, Niels Ørtenblad, Glenn Björklund
PURPOSE: This study aimed to examine the metabolic responses and pacing strategies during the performance of successive sprint time trials (STTs) in cross-country skiing. METHODS: Ten well-trained male cross-country skiers performed four self-paced 1300-m STTs on a treadmill, each separated by 45 min of recovery. The simulated sprint time trial (STT) course was divided into three flat (1°) sections (S1, S3, and S5) involving the double poling subtechnique interspersed with two uphill (7°) sections (S2 and S4) involving the diagonal stride subtechnique...
December 2016: Medicine and Science in Sports and Exercise
Melissa I Gomis, Robin Vestergren, Helena Nilsson, Ian T Cousins
The contribution of direct (i.e., uptake of perfluorooctanoic acid (PFOA) itself) and indirect (i.e., uptake of 8:2 fluorotelomer alcohol (FTOH) and metabolism to PFOA) exposure to PFOA serum concentrations was investigated using a dynamic one-compartment pharmacokinetic (PK) model. The PK model was applied to six occupationally exposed ski waxers for whom direct and indirect exposures via inhalation were characterized using multiple measurements with personal air sampling devices. The model was able to predict the diverging individual temporal trends of PFOA in serum with correlation coefficients of 0...
July 5, 2016: Environmental Science & Technology
Hyo Taek Lee, Hyo Lyun Roh, Yoon Sang Kim
[Purpose] Efficient management using exercise programs with various benefits should be provided by educational institutions for children in their growth phase. We analyzed the heart rates of children during ski simulator exercise and the Harvard step test to evaluate the cardiopulmonary endurance by calculating their post-exercise recovery rate. [Subjects and Methods] The subjects (n = 77) were categorized into a normal weight and an overweight/obesity group by body mass index. They performed each exercise for 3 minutes...
January 2016: Journal of Physical Therapy Science
Hyo Taek Lee, Hyo Lyun Roh, Yoon Sang Kim
[Purpose] Currently, various simulators are produced and used for athlete's exercise, rehabilitation, and training. In this study, we analyzed the kinematic factors of sectional and total movements in healthy participants by providing group-dependent information during simulated exercise. [Subjects and Methods] Participants in this study included 26 male adults (non-experts and experts); experts held a certificate issued by the Korea Ski Instructors Association. The elapsed times in each phase, the difference in the lower extremity angles, and muscle activity were computed through analysis of kinematic factors...
January 2016: Journal of Physical Therapy Science
Caroline Praz, Benedikt Fasel, Philippe Vuistiner, Kamiar Aminian, Bengt Kayser
PURPOSE: The purpose of this study was to estimate the energy cost of linear (EC) and vertical displacement (ECvert), mechanical efficiency and main stride parameters during simulated ski mountaineering at different speeds and gradients, to identify an optimal speed and gradient that maximizes performance. METHODS: 12 subjects roller skied on a treadmill at three different inclines (10, 17 and 24 %) at three different speeds (approximately 70, 80 and 85 % of estimated peak heart rate)...
May 2016: European Journal of Applied Physiology
E Andersson, G Björklund, H-C Holmberg, N Ørtenblad
To improve current understanding of energy contributions and determinants of sprint-skiing performance, 11 well-trained male cross-country skiers were tested in the laboratory for VO2max , submaximal gross efficiency (GE), maximal roller skiing velocity, and sprint time-trial (STT) performance. The STT was repeated four times on a 1300-m simulated sprint course including three flat (1°) double poling (DP) sections interspersed with two uphill (7°) diagonal stride (DS) sections. Treadmill velocity and VO2 were monitored continuously during the four STTs and data were averaged...
April 2017: Scandinavian Journal of Medicine & Science in Sports
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