GROUND REACTION FORCE COMPARISON BETWEEN BOTH FEET DURING GIANT SLALOM TURNS IN ALPINE SKIING

The purpose of this study was to measure the difference in normal force under both feet during alpine skiing giant slalom turns. Eleven experienced alpine skiers performed a giant slalom course at race intensity. All trials were recorded synchronously using a video camera and a plantar pressure measuring system. The mean force on the grouped two feet varied from 0.7 BW at the start of a turn to 1.5 BW during the steering phase of a turn performed in a steep slope condition. When skiing on FLAT slope condition, it reached only 1.3 BW. Results also showed that the outside foot receives significantly more pressure than the inside foot during the entire turn except the initiation phase. This last finding is not affected by slope steepness

Effects of Different Training Intensity Distributions Between Elite Cross-Country Skiers and Nordic-Combined Athletes During Live High-Train Low

Purpose: To analyze the effects of different training strategies (i.e., mainly intensity distribution) during living high – training low (LHTL) between elite cross-country skiers and Nordic-combined athletes.Methods: 12 cross-country skiers (XC) (7 men, 5 women), and 8 male Nordic combined (NC) of the French national teams were monitored during 15 days of LHTL. The distribution of training at low-intensity (LIT), below the first ventilatory threshold (VT1), was 80% and 55% in XC and NC respectively. Daily, they filled a questionnaire of fatigue, and performed a heart rate variability (HRV) test. Prior (Pre) and immediately after (Post), athletes performed a treadmill incremental running test for determination of V˙O2max and V˙O2 at the second ventilatory threshold (V˙O2V T2), a field roller-skiing test with blood lactate ([La-]) assessment.Results: The training volume was in XC and NC, respectively: at LIT: 45.9 ± 6.4 vs. 23.9 ± 2.8 h (p < 0.001), at moderate intensity: 1.9 ± 0.5 vs. 3.0 ± 0.4 h, (p < 0.001), at high intensity: 1.2 ± 0.9 vs. 1.4 ± 02 h (p = 0.05), in strength (and jump in NC): 7.1 ± 1.5 vs. 18.4 ± 2.7 h, (p < 0.001). Field roller-skiing performance was improved (-2.9 ± 1.6%, p < 0.001) in XC but decreased (4.1 ± 2.6%, p < 0.01) in NC. [La-] was unchanged (-4.1 ± 14.2%, p = 0.3) in XC but decreased (-27.0 ± 11.1%, p < 0.001) in NC. Changes in field roller-skiing performance and in [La-] were correlated (r = -0.77, p < 0.001). V˙O2max increased in both XC and NC (3.7 ± 4.2%, p = 0.01 vs. 3.7 ± 2.2%, p = 0.002) but V˙O2V T2 increased only in XC (7.3 ± 5.8%, p = 0.002). HRV analysis showed differences between XC and NC mainly in high spectral frequency in the supine position (HFSU). All NC skiers showed some signs of overreaching at Post.Conclusion: During LHTL, despite a higher training volume, XC improved specific performance and aerobic capacities, while NC did not. All NC skiers showed fatigue states. These findings suggest that a large amount of LIT with a moderate volume of strength and speed training is required during LHTL in endurance athletes

Ski : connaissances scientifiques et entraînement

La fédération française de ski propose un exemple d'intégration des connaissances scientifiques dans la pratique d'entraînement pour optimiser la performanc

Ski alpin : championnats du monde à Val d'Isère

Bilan des championnats du monde de ski alpin 2009 à Val d'Isère : présentation technique des disciplines et performances des athlètes français, principes mécaniques communs aux différentes discipline

Contribution à l'analyse de la relation entre la filière aérobie et les performances sportives des skieurs alpins en filière d'accès au haut-niveau de 1994 à nos jours (détermination de facteurs aérobies prédictifs de la performance)

Pour décrire la relation entre la performance en ski alpin et la filière aérobie, nous avons collecté les données de 1166 épreuves d effort d intensité maximale, effectuées par des skieurs alpins de 1994 à 2010. Il existe des différences anthropométriques selon la spécialité plus apparentes chez les hommes que chez les dames. Mais l âge moyen n étant pas identique dans toutes les disciplines, il pourrait expliquer ces observations. L âge, le poids et l IMC sont les principaux facteurs de modélisation de la spécialité (Technique, Vitesse ou Polyvalent) : les plus lourds et les plus âgés sont plus généralement des spécialistes de vitesse. Le suivi longitudinal suggère une sensibilité des facteurs aérobies aux contenus d entraînement du skieur. Les résultats des analyses factorielles multi-variées suggèrent qu il n existe pas un facteur aérobie isolé qui soit directement lié à la performance, mais un ensemble de ces facteurs (VO2, VCO2, VE et PMA ou VMA ). Néanmoins, il ressort que les skieurs très performants ont le plus souvent : un âge, un poids, une taille, un IMC, une VO2max, un VCO2max, un VEmax et une PMA supérieurs à la moyenne. Cette étude confirme l implication, mais non-unique du métabolisme aérobie dans la performance. Le travail aérobie devrait être encouragé dans le cursus d entrainement des skieurs alpins souhaitant accéder au plus haut niveau. Cependant il ne faut pas négliger l intervention dans la performance de nombreux autres facteurs intrinsèques (capacités de force, qualités techniques du skieur, habiletés mentales ) et extrinsèques (matériels, environnement ).In order to describe the link between alpine skiing performances and the aerobic metabolism, we collected data from 1166 maximal exercise tests on skiers from 1994 to 2010. There are anthropometric differences, more visible for men than women, according to their specialty. However, these differences could result from the varying average age per discipline. Age, weight and BMI are the main discriminating factors to establish their specialty ( technique , speed or all-rounder group), the oldest and heaviest usually being speed group experts. The timeline monitoring shows that aerobic power changes in regard to different training loads. Multi-variate factor analysis results show there isn't a single isolating factor directly associated to performance, but rather a group of factors (VO2, VCO2, VE and Maximal power or speed output ). Nonetheless, the highest achieving skiers are most often above average in age, weight, BMI, height,VO2max, VCO2max, VEmax and maximal power output This study shows the implication of aerobic metabolism, among others, in performance. Aerobic training should be encouraged in training programs for alpine skiers who wish to reach the highest level. However, the intervention of other intrinsic factors, such as strength, technicality, cerebral faculties, or extrinsic factors, such as equipment or environment, must not be disregarded.GRENOBLE1-BU Médecine pharm. (385162101) / SudocSudocFranceF

Reliability of Alpine Ski Racing-Specific Field Test: The 80s-Slide-Test

International audiencePurpose: The purpose of this study was to determine the test-retest reliability of the 80s-slide-test in well-trained alpine ski racers. Methods: The sample consisted of 8 well-trained alpine ski racers (age = 17.8 [0.7] y old; height = 1.80 [0.09] m; body mass = 72.1 [9.5] kg) who performed a lab-based maximal graded test on cycle ergometer and three 80s-slide-tests in 4 separate essions. The 80s-slide-test consisting of maximal push-offs performed for 80s on a 8-ft slide board. Oxygen uptake ((V)Over dotO(2)) and heart rate (HR) were recorded continuously. Blood lactate ([La](b)) was determined immediately prerun, followed by 3 minutes postrun. Three minutes after the completion of the session, the subjects were asked to indicate their rate of perceived exertion using Borg scale ranging from 6 to 20. Total and every 10s mean push-offs number were assessed by camera. Typical errors of measurement, intraclass correlation coefficients, and smallest worthwhile change were calculated. Results: The 80s-slide-test showed strong reliability for total push-offs number, (V)Over dotO(2peak), (V)Over dotO(2mean), HRpeak, and HRmean. Delta[La](b), fatigue index, and the rate of perceived exertion were moderately reliable. Conclusion: The 80s-slide-test is a reliable test for well-trained alpine ski racers and can be used easily by trainers

Influence of slope steepness, foot position and turn phase on plantar pressure distribution during giant slalom alpine ski racing - Fig 3

<p><b>a, b. Relative contribution of the pressure time integral (relPTI, %) applied to three plantar regions along the A-P axis.</b> Data of the Heel, Midfoot and Forefoot region of the outside foot are shown, for a) flat and b) steep slopes during the turn. Error bars represent the standard deviation.</p

Return to Sport Among French Alpine Skiers After an Anterior Cruciate Ligament Rupture: Results From 1980 to 2013

International audienceBackground: There is little known about return to sport and performance after anterior cruciate ligament (ACL) tear in high-level alpine skiers. Purpose: To analyze the parameters that influence the return to sport and performance after an ACL tear in French alpine skiers from 1980 to 2013. Study Design: Descriptive epidemiology study. Methods: The study population included 239 male and 238 female skiers who competed on the national French alpine ski team for at least 1 season between 1980 and 2013 in the speed (downhill and super-G) and technical disciplines (giant slalom and slalom). Two groups were formed: group 1 (G1) included athletes who had sustained an ACL rupture, and group 2 (G2) included athletes who had never sustained an ACL rupture. Three performance indicators were selected: International Ski Federation (FIS) points calculation, FIS ranking, and podium finishes in the World Cup, World Championships, and Olympic Games. Results: The first-decile FIS points and international FIS ranking showed that G1 skiers obtained better performance than did G2 skiers. The mean ± SD career length of G1 skiers (men, 7.9 ± 4.7 years; women, 7.1 ± 4.1 years) was longer than that of G2 skiers (men, 4.5 ± 3.3 years; women, 4.2 ± 3.5 years). In addition, 12.8% (61 of 477) of the skiers achieved at least a podium finish during their careers: 23.0% (34 of 148) in G1 and 8.3% (27 of 329) in G2. The mean age at ACL rupture was 22.6 ± 4.1 years for men and 19.9 ± 3.5 years for women. In G1, 55 podiums were achieved before ACL rupture and 176 after in all competitions. Skiers who improved their performances after ACL rupture were significantly younger (men, 22.2 ± 3.0 years; women, 18.7 ± 2.2 years; P\.0001) at the time of injury than those showing a performance deterioration after ACL rupture (men, 25.3 ± 4.2 years; women, 22.4 ± 4.0 years). All skiers who had ACL tears continued their competitive careers after the injury. Conclusion: The overall results showed that it is possible to return to preinjury or even higher levels of performance after an ACL rupture and that age is the main element that guides postsurgical recovery