This investigation aimed to employ novel analyses to longitudinal jump testing data gathered from competitive weightlifters to identify how certain biomechanical and performance characteristics obtained from the countermovement jump (CMJ) relate to changes in weightlifting performance over time and if they can differentiate higher and lower performers. A linear mixed-effect model was used to assess and compare the ability of countermovement jump height and net-impulse to predict Sinclair weightlifting total. CMJ force-time waveforms were compared in cross-sectional and repeated measures analyses to distinguish the force application patterns of higher-performing weightlifters and if they change over extended periods of training. It was found that both jump height and net impulse were significant predictors of Sinclair weightlifting total; however, likely due to changes in body mass within individuals over time, net impulse was a better predictor. The primary differentiator between higher and lower-performing weightlifters within the countermovement jump was the magnitude of force produced during the propulsive phase. No changes to the athlete’s force-time waveforms were observed across three testing sessions separated each by a year. Over the three testing sessions, no significant change in jump height was found; however, net impulse increased over time. The findings of this dissertation demonstrate that countermovement jump net impulse is a beneficial metric to monitor in competitive weightlifters as it demonstrated the capacity to predict changes in weightlifting performance, differentiated levels of performers, and changes over extended periods of training.

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Introduction : Les joueurs de hockey sur glace effectuent des mouvements asymétriques en utilisant la rotation du torse et des hanches lors des passes et des tirs. Les asymétries entre les segments corporels peuvent avoir un impact sur la capacité de sprints répétés, la puissance verticale lors de sauts à contre-bas et les performances sportives générales. La force isométrique de la hanche et le saut à contre-bas sont couramment évalués chez les joueurs de hockey sur glace en raison de leurs relations avec les performances en patinage et l'incidence des blessures à l'aine, respectivement. Objectif : Cette étude vise explorer si les asymétries obtenues lors des évaluations des forces isométriques de la hanche et des sauts à contre-bas sont associées à celles observées lors du patinage. Méthodes : Trente-sept joueurs professionnels de l'hockey sur glace ont effectué des évaluations hebdomadaires de force et de saut de la hanche et ont porté des centrales inertielles pendant les séances sur glace tout au long des saisons pré et compétitives. Les accélérations sont mesurées pour les deux jambes et ont été utilisées pour calculer les asymétries inter-membres, en pourcentage. Résultats : Parmi tous les paramètres mesurés, seule l'asymétrie dans le pic de la force de l’attérissage du saut à contre-bas a dépassé 10% pour toutes les positions (22,1%) et par position (21,3% - 22,6%). Les joueurs de centre et à la défense ont mené à plusieurs relations modérées à grandes entre différentes asymétries lors des évaluations hors-glace (r: -0,67 - 0,38, p <0,01). Toutes les positions ont montré des relations modérées à grandes entre la résistance à la hanche et la charge de patinage sur la glace et la force moyenne par foulée (r: -0,32 - 0,56, p <0,05). Les joueurs de centre ont montré des relations modérées entre le saut à contre-bas et des asymétries sur la glace (r: -0,31 - 0,43, p <0,01). Conclusion Cette étude a révélé qu'il existe des relations significatives entre les asymétries sur- et hors glace dans le hockey professionnel masculin. Les résultats de cette étude fournissent également aux intervenants auprès de cette population des valeurs de référence pour les asymétries sur glace et hors glace. / Introduction Ice-hockey players develop asymmetrical movement patterns by favoring rotation through the torso and hips while passing and shooting. Interlimb asymmetries have been shown to affect repeated sprint ability, vertical and horizontal countermovement jump power, and general athletic performance. Isometric hip strength and the countermovement jump are commonly assessed in ice-hockey players because of their relationships with skating performance and incidence of groin injuries, respectively. Purpose: This study explored whether asymmetries returned during isometric hip strength and countermovement jump assessments relate to those from stride-by-stride analyses. Methods: Thirty-seven professional ice-hockey players performed weekly hip strength and jump assessments and wore inertial momentum units during on-ice sessions throughout the pre- and competitive seasons. Data were either available for both limbs and were utilized to calculate inter-limb asymmetries, or as an asymmetry percentage. Results: Among all parameters measured, only the CMJ peak landing force asymmetry exceeded 10% for all positions (22.1%) and by position (21.3% - 22.6%). Centers and Defense positions returned several moderate to large relationships between fitness assessment asymmetries (r: -0.67 – 0.38, p < 0.01). All positions returned moderate to large relationships between hip strength and on-ice skating load and average force per stride (r: -0.32 – 0.56, p < 0.05). Centers returned moderate countermovement jump and on-ice asymmetries (r: -0.31 – 0.43, p < 0.01). Conclusion: This study revealed that significant relationships exist between on- and off-ice asymmetries in men’s professional ice-hockey. The results from this study also provide practitioners with reference values for on- and off-ice asymmetries.

This thesis work comprises the working and simulation procedures being involved in simulating motion capture data in AnyBody Modeling System. The motion capture data used in this thesis are ballet movements from dancers of Östgöta ballet and dance academy. The ballet movements taken into consideration are the arabesque on demi-pointe and pirouette. The arabesque on demi-pointe was performed by two dancers but the pirouette is performed by only one dancer. The method involved recording ballet movements by placing markers on the dancer's body and using this motion capture data as input to AnyBody Modeling System to create a musculoskeletal simulation. The musculoskeletal modeling involved creating a very own Qualisys marker protocol for the markers placed on the ballet dancers. Then implementing the marker protocol onto a human model in AnyBody Modeling System by making use of the AnyBody Managed Modeling Repository (TM) and obtain the kinematics from the motion capture. To best fit the human model to the dancer's anthropometry, scaling of the human model is done, environmental conditions such as the force plates are provided. An optimization algorithm is conducted for the marker positions to best fit the dancer's anthropometry by running parameter identification. From the kinematics of the motion capture data, we simulate the inverse dynamics in AnyBody Modeling System. The simulations explain a lot of parameters that describe the ballet dancers. Results such as the center of mass, the center of pressure, muscle activation, topple angle are presented and discussed. Moreover, we compare the models of the dancers and draw conclusions about body balance, effort level, and muscles activated during the ballet movements.