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Yujiang Xiang

Human carrying is simulated in this work by using a skeletal digital human model with 55 degrees of freedom. An optimization-based approach is used to predict the carrying motion with symmetric and asymmetric loads. In this process, the model predicts joint dynamics using optimization schemes and task-based physical constraints. The results indicate that the model can predict different carrying strategies during symmetric and asymmetric load-carrying tasks. The model can also indicate the risk factors for extreme loading situations. With such robust prediction capability, the model could be used for biomedical and ergonomic studies.

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Brianne N. Schwark, Sasho J. Mackenzie and Eric J. Sprigings

The primary purpose of this study was to determine the optimal release conditions and corresponding arm movement pattern for the free throw for players classified as 3 to 4.5 on the international player classification system in wheelchair basketball. A 2-D, three-segment simulation model was used to investigate this problem. The computational process involved a two-step optimization scheme in which an outer computational loop was used to optimize the magnitude and timing of the muscle torques that generate the arm's motion, and an inner computational loop was used to determine the optimal angle and speed of the ball at the moment of release. The inner optimization loop revealed that Brancazio's (1981) and Hay's (1993) approaches to determining the optimal release angle produced identical results. The lowered seated height of the wheelchair basketball player required that the ball be released at a steeper angle with greater vertical velocity, and hence the need for greater shoulder torque. For the wheelchair player, the peak shoulder flexion torque generated by the model was reduced by approximately 43% when the upper arm was initially positioned at an angle approximately 40° below the horizontal, as compared to being positioned at an angle of 10° above the horizontal. For the wheelchair player, the optimal release angle and speed for a ball released at a horizontal distance of 4.09 m from the center of the basket, and 1.30 m below the rim, was computed to be 53.8° and 7.4 m/s, respectively.

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Reza Abdollahipour, Ludvík Valtr and Gabriele Wulf

According to the OPTIMAL (Optimizing Performance Through Intrinsic Motivation and Attention for Learning) theory of motor learning ( Wulf & Lewthwaite, 2016 ), three factors are key to optimal motor performance and learning. Two of these factors are motivational in nature (enhanced expectancies

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David L. Carey, Justin Crow, Kok-Leong Ong, Peter Blanch, Meg E. Morris, Ben J. Dascombe and Kay M. Crossley

Australian football. 3 Currently, physical-preparation staff are tasked with balancing the training guidelines associated with injury-risk reduction and performance improvement when prescribing training loads. Mathematical optimization is a method that may help in this process, particularly as more data on

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Trent Stellingwerff, Ingvill Måkestad Bovim and Jamie Whitfield

Middle-distance running events are highly complex from a performance optimization point of view. For example, elite middle-distance specialists need to have the aerobic system development approaching marathoners, coupled with some of the mechanical properties of elite sprinters, while concurrently

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Gary J. Slater, Jennifer Sygo and Majke Jorgensen

sprint performance ( Hargreaves et al., 1997 ). Taken together, this provides potential opportunities for nutritional interventions that could impact on training and performance, including buffering against acidosis for longer sprints (i.e., 400 m) and optimization of the phosphagen energy systems for

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Garrett Bunyak

optimized to maximize performance in sport ( Jette, 2006 ; Markula, 2003 ). As studies of foxhunting, cockfighting, and greyhound racing illustrate, sport often directly or indirectly shapes, manages, and controls nonhuman animal lives and bodies. As a result of this state of affairs, I extend the

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Brad Donohue, Yulia Gavrilova, Marina Galante, Elena Gavrilova, Travis Loughran, Jesse Scott, Graig Chow, Christopher P. Plant and Daniel N. Allen

FBT, but the theoretical underpinnings of FBT were shifted from a focus on symptom reduction to performance optimization in TOPPS. Similarly, FBT protocols were modified to fit sport culture in TOPPS. In the optimization approach, feelings, thoughts and behaviors are conceptualized to reciprocally

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Levi Heimans, Wouter R. Dijkshoorn, Marco J.M. Hoozemans and Jos J. de Koning

effect based on aerodynamic characteristics of team members can result in a more specific estimation for required power per position. The purpose of this study is to optimize team efficiency by estimating the drafting effect as a function of the aerodynamic characteristics. Therefore, we determine the

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Rositsa T. Raikova

This commentary emphasizes three points of discussion. (a) The terminology: The terms multifunctional, synergisic, antagonistic muscles, and synergistic and antagonistic coactivations are discussed and the conclusion is drawn that they could not be used without mentioning the particular joint motion. (b) The importance of the external joint moments for activation of the muscles is confirmed on the basis of logical and mechanical considerations. Not all experimental results, however, could be explained by this means. (c) The optimization criterion: Prilutsky's conclusion concerning the predicted muscle force proportionality to the muscle moment arm and PCSA is confirmed using a simple analytical solution of the optimization problem. It is shown, however, that the proportionality to the PCSA is a consequence of the chosen optimization criterion.