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I denna översiktsartikel granskades 17 randomiserade kontroll studier som undersökt hur excentrisk träning har påverkat hopphöjd, muskelstyrka och effektutveckling hos tränade och skadefria individer, med mål att svara på följande två frågeställningar; 1) ”Är excentrisk träning ett effektivt sätt att träna för att utveckla hopphöjd, muskelstyrka och effektutveckling för tränade och skadefria individer?” 2) ”Om det är det, hur bör denna träning i så fall se ut?”. Majoriteten av insamlade studier kunde inte urskilja några signifikanta förändringar till följd av excentrisk träning. Endast sex av 17 studier kunde påvisa akuta såväl som kortsiktiga signifikanta förbättringar av hopphöjd, muskelstyrka och effektutveckling. Dock ifrågasätts relevansen av dessa fynd då effektstorleken inte rapporterats i alla studier samt att utformningen av studierna varierat från en studie till en annan. Sammantaget lyckades inte de granskade studierna bevisa att excentrisk träning är en effektiv metod för att utveckla hopphöjd, muskelstyrka och effektutveckling hos tränade och skadefria individer. / In this review 17 randomized control studies were reviewed that had examined the effects of eccentric training regarding jump height, strength and power for trained and non-injured individuals. The purpose of the review was to answer the following two questions at issue; 1) “Is eccentric training an efficient method to enhance jump height, strength or power for trained and non-injured individuals?” 2) “If so, how should that training regime be designed?”. Most of the included studies could not distinguish any significant changes because of eccentric training. Only six out of 17 studies could show acute as well as short term significant improvements in jump height, strength and power. The relevance of these findings is questioned since effect size has not been reported in all the included studies. The variety between the different interventions in each study also makes it difficult to compare the results between one study and another. In conclusion, the reviewed studies failed to show that eccentric training is an effective method to enhance jump height, strength and power for trained and non-injured individuals.

Si de nombreuses études ont été consacrées à l’analyse des grands tours préparatoires aux sorties, aux sorties elles-mêmes et aux lâchers de barre en barre fixe ou barre supérieure de barres asymétriques, les éléments avec envol pour passer d’une barre à l’autre aux barres asymétriques (lâcher la barre inférieure pour saisir la barre supérieure ou l’inverse) n’ont, à notre connaissance, pas fait l’objet de telles études. Cette thèse de doctorat présente dans sa première partie une analyse cinématique du « pieds barre temps de ventre » ainsi qu’une analyse des moments cinétique et d’inertie mis en jeu par deux groupes de gymnastes, des expertes et des novices, lors de la réalisation de ce mouvement. La deuxième partie met en évidence des lois de contrôle moteur utilisées par les deux groupes pour réaliser l’élément. Afin de déterminer si les mouvements des deux groupes sont susceptibles d’améliorations et si la trajectoire créée au lâcher de la barre inférieure ou la gestuelle mise en jeu influence davantage la performance, une optimisation du pieds barre temps de ventre est proposée dans la troisième partie. Enfin, l’effet de l’introduction d’une loi de contrôle moteur dans le processus d’optimisation sur le réalisme des mouvements optimisés est envisagé. / Many studies were dedicated to the analysis of backward giant circles prior to release, releases itself or release-regrasp skills on high bar or uneven bars. To our knowledge, skills with flight phase to release low bar and regrasp high bar or the contrary were not studied yet. The first chapter of this doctoral thesis is dedicated to a kinematic analysis of the “counter movement forward in flight” on uneven bars and to the moment of inertia and angular momentum recorded for two groups of gymnasts performing this task: an expert group and a novice group. The second chapter highlights motor control laws used by the gymnasts of both groups. An optimization of the counter movement forward in flight was carried out in the third chapter in order to know if the movements of both groups may be improved and whether body mass center trajectory or body movements in flight most influence final performance. Effects of introducing a motor control law in the optimization process on the realism of optimized movements were studied.

Syfte: Syftet för studien var att undersöka om isometric mid-thigh pull (IMTP) tillsammans med (CMJ) kan anses som lämpliga testmetoder för att mäta prestation i hoppförmåga inom parkour/freerunning (PK/FR). Vi undersökte detta genom att mäta traceurers maximala styrka och explosiva styrka i de nedre extremiteterna, för att sedan jämföra resultaten med fysiskt aktiva idrottsstudenter på högskolenivå. Vi undersökte även om IMTP och CMJ korrelerar med varandra. Urval: 23 personer, 11 traceurer och 12 fysiskt aktiva idrottare rekryterades för denna studie. Metod: vi mätte maximal styrka: Peak force (PF) IMTP (N) på kraftplatta och maximal vertikal hopphöjd: CMJ (cm) på IR-matta. Statistisk analys: Shapiro Wilks användes för normalfördelningar, en oberoende tvåvägs Mann-Whitney U t-test användes för att undersöka skillnader mellan grupperna. Två Spearmans- och ett Pearsons korrelationskoefficienttest användes för att undersöka samband mellan IMTP och CMJ. Resultat: PK gruppen var normalfördelad i alla variabler IMTP (N) och CMJ (cm) men kontroll (KTRL) gruppen var ej normalfördelad i CMJ (cm) och gav utslag för IMTP (N). PK gruppen uppnådde ett IMTP (N) medianvärde på: 2269,9 ± 661.72N och CMJ medianvärde på 36.2 ± 7.48 cm. KTRL gruppen uppnådde ett IMTP (N) medianvärde på: 1626.9 ± 501.95N och ett CMJ medianvärde på: 31.8 ± 5.91cm. Ingen statistiskt signifikant skillnad hittades mellan grupperna, men traceurerna visar en trend för ett högre IMTP (N) värde. Ett statistiskt signifikant samband fanns mellan IMTP och CMJ för hela populationen. R-värde = 0.404. R² värde avrundades till 23%. P-värde = 0.031. Inget statistiskt signifikant samband fanns för PK eller KTRL grupperna individuellt. Slutsats: Traceurerna och de fysiskt aktiva högskolestudenterna visade snarlika resultat i maximal styrka och explosiv styrka i denna studie. Resultaten klassificerades som lågpresterande i förhållande till referensvärden från tidigare studier på traditionella idrotter för IMTP och på traceurer i CMJ. Den maximala styrkan från IMTP tycks förklara 23% av hoppförmågan i CMJ vilket kan vara en indikation av betydelse för traceurers prestation. Framtida forskare uppmuntras använda IMTP och CMJ på större populationer för att kartlägga traceurers force-velocity kurvor och/eller inrätta skadepreventiva program för PK/FR. Begrepp: Traceur (FRE) = tracer (ENG), spårare (SWE). Traceur = manlig Parkour utövare. Traceuse = kvinnlig Parkourutövare. PK/FR = Parkour/Freerunning. PK = Studiens Parkour grupp. KTRL = Studiens kontrollgrupp. Countermovement jump (CMJ), (N) = Newton. 1RM = en 100% maximal ansträngd repetition. / Purpose: The aim of the study was to investigate if IMTP together with CMJ can be considered as suitable methods to measure performance in jumping ability in PK/FR. We investigated this by measuring maximal strength and explosive strength of the lower extremities of traceurs and comparing the results with physically active college student athletes. We investigated also if IMTP and CMJ correlate with each other. Recruitment: 23 people, 11 traceurs and 12 psychical active collegial sport athletes were recruited for this study. Method: We measured maximal strength: PF IMTP (N) on force plate and maximal vertical jump height: CMJ (cm) on IR mat. Statistical analysis: Shapiro Wilks was used for normal distribution; an independent two-way Mann-Whitney U t-test was used to examine differences between groups. Linear regression tests with two Spearman's and one Pearson's correlation coefficient tests were used to examine relationships between IMTP and CMJ. R² values were calculated. Results: The PK group was normally distributed in IMTP (N) and CMJ (cm). The KTRL group was not normally distributed in CMJ (cm) and flagged an indication for IMTP (N). The PK group achieved a IMTP (N) median of 2269.9N SD ± 661.72N. And CMJ median of 36.2cm SD ± 7.48cm. The KTRL group achieved a IMTP (N) median of 1626.9N SD ± 501.95N. And a CMJ median of 31.8cm SD ± 5.91cm. No statistically significant differences were found between the groups. But the traceurs showed a trend for a higher IMTP (N) value. A statistically significant relationship was found between IMTP and CMJ for the entire population. R value = 0.404. R² value was rounded to 23%. P-value = 0.031. No statistically significant relationships were found for the PK- or the KTRL groups individually. Conclusion: The traceurs and the physically active college students were similar in maximal- and explosive strength in this study. The results were classified as low performance in comparison to previous studies of traditional sports on IMTP and on traceurs on CMJ. The maximal strength from the IMTP appears to account for 23% of the jumping ability in CMJ which may be an indication of importance for traceurs performance. Future researchers are encouraged to use IMTP and CMJ on larger populations to map force-velocity curves and/or establish injury prevention programs for PK/FR. Concepts: Traceur (FRE) = tracer (ENG), tracker (SWE). Traceur = male Parkour practitioner. Traceuse = female Parkour practitioner. PK/FR = Parkour/Freerunning. PK = The study's Parkour group. KTRL = Study control group. Countermovement jump (CMJ), Isometric mid-thigh pull (IMTP). 1 RM = a 100% maximum effort repetition. / <p>Ämneslärarprogrammet, Specialidrott</p>

Bakgrund: Syftet med denna studie var att undersöka effekten av sju dagars tillskott av betain (2,5 gram/dag) på prestationsförmågan i idrottsspecifika tester för manliga vältränade cykelatleter. Metod: Sex (n=6) manliga testpersoner (genomsnitt ± standardavvikelse ålder, 31,7 ± 10,2 år; längd, 188,2 ± 3,6 cm; kroppsvikt; 82,5 ± 7,6 kg; fettfri massa, 71,6 ± 7,3 kg) genomförde förtester bestående av fem counter movement jumps, fyra stycken 12 s wingate-sprinter med 2,5 minuters aktiv vila följt av fem ytterligare counter movement jumps. De blev sedan indelade slumpmässigt i betain- eller placebogrupper. Första testet etablerade basvärden och eftertest ”1” samt ”2” föregicks med antingen sju dagars tillskott med placebo (2,5 g maltodextrin plus 12,5 mg riboflavin) eller betain (2,5 g trimetylglycin plus 12,5 mg riboflavin). Riboflavin användes för att undanröja den fiskliknande doften som kan uppstå vid tillskott av betain. Doseringen bestod av fyra kapslar per dag till måltid, varav två kapslar intogs på morgonen eller förmiddagen (före träning) och två kapslar intogs på eftermiddagen eller kvällen (efter träning). Vi använde oss av en dubbelblindad, kontrollerad randomisering cross-over design; med en veckas washout mellan placebo och betain. Maximum Peak Power, Average Peak Power, Maximum Average Power, Mean Average Power, Mean Relative Power Drop, Maximum Relative Power Drop, CMJ-Medel och CMJ-Max före och efter sprinterna analyserades med two-tailed t-test 2 och 3 för att jämföra skillnader före och efter intag av tillskott samt skillnaderna mellan grupperna.Resultat: Inga signifikanta skillnader kunde noteras. Konklusion: En veckas tillskott av betain gav inte någon signifikant förbättring jämfört med placebo i hopp- och sprintförmåga samt förmåga att ta ut sig själv maximalt hos aktiva cyklister. Fler studier med framförallt större testgrupper efterlyses för att utvärdera betainets ergogena effekt bland aktiva atleter. / The effect of betaine supplementation on counter movement jumps and sprint performance among male bicycle athletes Background: The purpose of this study was to investigate the effect of a seven days supplementation regimen with betaine (2,5 grams per day) on counter movement jumps and sprint performance in trained male bicyclists. Method: Six (n=6) male subjects (mean ± standard deviation age, 31,7 ± 10,2 years; height, 188,2 ± 3,6 cm; bodyweight, 82,5 ± 7,6 kg; lean body mass, 71,6 ± 7,6 kg) completed a 21 day study involving five counter movement jumps (no arm swing) followed by 4 consecutive modified 12 second Wingate sprints on a bicycle ergometer with active rest (2,5 minutes) followed by another set of five counter movement jumps. A double blind, controlled randomized cross over design was used and there was a 1 week washout between the supplementation startup for each group. Following pre-testing (baseline) the participants were randomly divided into groups by choosing one of the following supplements: “12” Placebo –2,5 grams of maltodextrine plus 12,5 mg riboflavin or “11” – Active 2,5 grams of trimethylglycine plus 12,5 mg riboflavin. Riboflavin was used so mask the “fishy odor syndrome” effect of high intakes of trimethylglycine that may cause trimethyluria. Daily consumption of capsules was divided into two doses of two capsules each with meals. One dose (two capsules) was consumed in the morning and one dose in the evening. The following variables were analyzed: Maximum Peak Power, Average Peak Power, Maximum Mean Power, Average Mean Power, Maximum Relative Power Drop, Average Relative Power Drop, Mean CMJ-Pre + Post sprints and Maximal CMJ-Pre + Post sprints. Results: None of the parameters showed statistical significance. Conclusion: Our study indicates that seven days of betaine ingestion does not seem significantly improve counter movement jump or sprint capacity in male trained bicyclists. Larger studies are needed to investigate the performance enhancing effects of betaine, especially among high performance athletes.

Le caractère participatif et interactif du Web social contribue à la transformation du militantisme féministe avec l’émergence du blogging et des médias sociaux. Les féministes occupent les espaces numériques pour explorer leur identité et leur conception du féminisme(s), socialiser, organiser leurs luttes ou rendre saillantes leurs revendications transformatrices. Néanmoins, l’exposition de soi en tant que féministe dans le Web social n’est pas sans risque. Cette thèse cherche à comprendre les conséquences des cyberviolences sur les trajectoires individuelles de militant·e·s féministes en France et au Québec. Dans les deux cas d’étude, les cyberviolences sont utilisées comme des armes politiques contre les féministes, qui représentent des cibles de premier choix. Dans un contexte de polarisation du débat public et de la montée des rhétoriques antiféministes en ligne, cette forme de violence produit des conséquences multiples sur le plan biographique et militant tout comme sur les usages des féministes du Web social. Les cyberviolences s’inscrivent dans un dispositif d’insécurité en ligne, qui rend les espaces numériques particulièrement hostiles et violents pour les militant·e·s féministes, augmentant ainsi les coûts du militantisme féministe. Conceptualisant l’engagement féministe tout comme les (cyber)violences à travers un continuum en ligne et hors-ligne, j’utilise une approche multimodale qui me permet de contextualiser les phénomènes en ligne par rapport à ceux hors-ligne. Les matériaux de cette enquête reposent sur une ethnographie en ligne des plateformes numériques Facebook, Twitter, Instagram et YouTube ainsi que la réalisation de 50 entretiens semi-dirigés avec des féministes à Paris (N26) et Montréal (24). Les entretiens sont construits de manière hybride entre des récits de vie et des entretiens sur traces. Sur le plan théorique, mon enquête mobilise les outils de la sociologie des mouvements sociaux à travers l’approche processuelle de l’engagement pour analyser les trajectoires des militant·e·s ainsi que ceux de la sociologie des usages des dispositifs sociotechniques pour appréhender les pratiques numériques des féministes. En marge de ces théorisations, j’intègre une conceptualisation relationnelle de l’espace qui me permet non seulement de lier ces deux approches théoriques distinctes, mais aussi d’opérer mon analyse comparative entre les espaces militants de la France et du Québec. Mes résultats de recherche montrent de quelle manière les acteurs antiféministes se saisissent des opportunités technologiques pour élargir leur répertoire et leurs stratégies d’action. La littérature identifie quatre stratégies qui sont utilisées par les contre-mouvements : recruter, créer des dommages, démobiliser et neutraliser. Je propose d’intégrer la stratégie de l’épuisement à ce répertoire d’action des contre-mouvements. Si les stratégies d’action déjà étudiées sont d’ordre organisationnel en attaquant les mouvements féministes, celle que je propose est plutôt individualisée en ciblant explicitement les militant·e·s féministes à titre personnel. Cette stratégie se dévoile à travers différentes tactiques comme celle du trolling, des raids numériques et de la cybersurveillance. Ces différentes tactiques représentent des formes de répression indirecte de l’engagement féministe dans un contexte de fort backlash antiféministe dans les univers en ligne et hors-ligne. Mon analyse comparative montre que l’identité des acteurs antiféministes les plus impliqués dans la (re)production des cyberviolences n’est pas la même selon les cas : la manosphère versus la fachosphère. Cela s’explique par les différences contextuelles et structurelles entre les cas et l’état des lieux de l’antiféminisme sur le terrain. Enfin, mes résultats montrent un cadrage différent des cyberviolences selon les cas d’étude. En France, les cyberviolences sont davantage problématisées comme un problème public autour de la notion de cyberharcèlement, alors qu’au Québec il est davantage question de prévention de la violence et de l’extrémisme violent au vu des conséquences mémorielles des attentats de l’École Polytechnique, de la Grande Mosquée de Québec et de l’attaque à la voiture-bélier revendiquée par un militant Incel à Toronto. Ce cadrage différencié explique notamment une intervention plus soutenue des autorités politiques en France pour sanctionner les différentes formes de cyberviolences comme les raids numériques. / The participatory and interactive nature of the social Web contributes to transforming feminist activism through the emergence of blogging and social media. Feminists occupy digital spaces to explore their identity and their conception of feminism, to socialize, to organize their struggles or to highlight their transformative claims. Nevertheless, exposing oneself as a feminist on the social web is not without risk. This thesis seeks to understand the consequences of online violence on the individual trajectories of feminist activists in France and Quebec. Both case studies use cyberviolence as a political weapon against feminists, who represent prime targets. In a polarized context of public debate and the rise of anti-feminist rhetoric online, this type of violence produces multiple consequences on biographical and activist levels and on feminists' uses of the social Web. Cyberviolence is part of a system of online insecurity, making digital spaces hostile and violent for feminist activists, thus increasing the costs of feminist activism. Conceptualizing feminist engagement and (cyber)violence across an online and offline continuum, my multimodal approach allows me to contextualize online versus offline phenomena. The data is from an online ethnography of Facebook, Twitter, Instagram and YouTube and 50 semi-directed interviews with feminists in Paris (N26) and Montreal (24). The interviews are built in a hybrid way between the lifetime storytelling method and the trace interviewing technique. On the theoretical level, my study mobilizes the tools of the sociology of social movements through the process approach of engagement to analyze activist trajectories and the sociology of the sociotechnical devices usages to apprehend feminist digital practices. On the sidelines of these theorizations, I use a relational conceptualization of space which allows me not only to link these two distinct theoretical approaches but also to carry out my comparative analysis between the activist spaces of France and Quebec. My results show how antifeminist actors seize technological opportunities to expand their repertoire and their strategies of action. The literature identifies four strategies that are used by counter-movements: recruit, damage, demobilize and neutralize. I propose to integrate the strategy of exhaustion into this repertoire of action. If the action strategies already studied are organizational in attacking feminist movements, this one is rather individualized by explicitly targeting feminist activists as persons. This strategy is revealed through various tactics such as trolling, digital raids and cyber surveillance. In the context of a strong anti-feminist backlash in the online and offline worlds, these different tactics are forms of indirect repression of feminist activism. My comparative analysis shows that the identity of antifeminist actors most involved in the (re)production of cyberviolence is not the same depending on the case: the manosphere versus the far-right networks. This is explained by the contextual and structural differences between the cases and the state of play of antifeminism on the ground. Finally, my results show a different framing of cyberviolence between France and Quebec. For the French case, cyberviolence is more problematized as a public problem around the notion of cyberbullying, while in Quebec it is more a question of preventing violence and violent extremism given the memorial consequences of the attacks on Polytechnique, the Grande Mosquée de Québec and the car-ramming attack claimed by an Incel activist in Toronto. This differentiated framing explains a more sustained intervention by the political authorities in France to sanction the different forms of cyberviolence such as digital raids.

Title: A comparison of dynamic abilities in nordic ski disciplines Aim: This dissertation aims to compare the dynamic abilities of cross country skiers and ski jumper in age between 12 to 15. Clarification of whether or not a training process of those two athlete groups has a crucial impact on the development of mentioned abilities compared to the other hobby sports group (target group). Methodology: This dissertation is conceived as empiric-theoretical. It analyses the results of samples to verify the hypothesis. There were three groups consisting of 10 samples (athletes) in total. The samples were tested in horizontal jumps (long jump, triple jump, multiple jumps) and vertical jumps (squat jump, counter movement jump). In all tests, it was decided to use only the best of all three attempts for the results. Findings: Development of dynamic abilities during the training process has a positive impact on their development in general. Both cross country skiers and ski jumpers achieved better results than the target group. Furthermore, ski jumpers performed better than cross country skiers. Keywords: physical health, sport performance, cross country skiing, ski jumping, squat jump (SJ), countermovement jump (CMJ), long jump, triple jump, multiple jumps