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Alif Laila Tisha, Ashley Allison Armstrong, Amy Wagoner Johnson and Citlali López-Ortiz

Production in Muscle Affected by Spastic CP Here, we present a conceptual model to provide possible mechanical explanations linking the muscle adaptations and muscle force production in muscle affected by spastic CP. The model aims to analyze the mechanical consequences of the 2 structural adaptations in

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Tibor Hortobágyi, Jeff Money, Donghai Zheng, Ronald Dudek, David Fraser and Lynis Dohm

This study compared muscle adaptations after 7 days of exercise with eccentric-overload (EO) or standard (ST) resistive training in young (20 years) and older (69 years) adults. Young EO and ST gained 103 and 30 N, respectively, and older EO and ST gained 63 and 25 N of strength, respectively (all p < .05). Types I and IIa MHC mRNA levels were not altered, but Type IIx levels decreased 31% and 63% after the first and seventh exercise bouts, respectively, in young and decreased 30% after the seventh bout in older participants (all p < 05), independent of loading type. Type 11a fiber increased. Type IIx decreased, and Type IIa increased in both age groups independent of loading type (all p < 05). Electron microscopy revealed no myofibrillar disruption in young or older muscle. These data suggest that short-term EO produces larger strength gains than does ST without muscle-cell disruption or loading-type-specific changes in MHC mRNA isoforms in young and older skeletal muscle.

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Diego Alonso-Fernandez, Yaiza Taboada-Iglesias, Tania García-Remeseiro and Águeda Gutiérrez-Sánchez

– 12 They represent a very important part in muscle adaptations, especially in the early stages of load training, while hypertrophy is more relevant in strength increases after the first 3 to 5 weeks. 10 In those early stages, in addition to the neural adaptations, there are other changes during the

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Karenina Arrais Guida Modesto, Pedro Ferreira Alves de Oliveira, Hellora Gonçalves Fonseca, Klaus Porto Azevedo, Vinicius Guzzoni, Martim Bottaro, Nicolas Babault and Joao Luiz Quagliotti Durigan

during training; we used a 60° knee-flexion angle, whereas the other authors used a 90° knee-flexion angle. 4 In fact, it is well established that muscle adaptations are dependent on the angular position used during training, that is, muscle length. 24 – 26 The longer the muscle length, the greater the

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Walter Herzog, Timothy Koh, Evelyne Hasler and Tim Leonard

We hypothesize that the neuromuscular system is designed to function effectively in accomplishing everyday movement tasks. Since everyday movement tasks may vary substantially in terms of speed and resistance, we speculate that agonistic muscles contribute differently to varying movement tasks such that the mechanical, structural, and physiological properties of the system are optimized at all times. We further hypothesize that a mechanical perturbation to the musculoskeletal system, such as the loss of an important joint ligament or the change of a muscle’s line of action, causes an adaptation of the system aimed at reestablishing effective function. Here. we demonstrate how the specificity of the cat ankle extensors is used to accommodate different locomotor tasks. We then illustrate how the loss of an important ligament in the cat knee leads to neuromuscular adaptation. Finally, we discuss the adaptability of skeletal muscle following an intervention that changes a muscle’s line of action, moment arm, and excursion.

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Ahmed Ismaeel, Michael Holmes, Evlampia Papoutsi, Lynn Panton and Panagiotis Koutakis

signaling was altered, as supplementation led to reduced phosphorylation and activation of p70 ribosomal protein S6 kinase, mitogen-activated protein kinase (MAPK) protein, p38, and extracellular signal-regulated kinase. In general, exercise promotes muscle adaptation by modulating gene expression and PS

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Brian Killinger, Jakob D. Lauver, Luke Donovan and John Goetschius

and Go, 30-s sit-to-stand, and 6-min walk tests). 24 While the precise mechanisms involved in muscle adaptations to BFR are not fully understood, 25 acute physiologic changes in muscle metabolism and neuromuscular function during BFR exercises have been suggested. Researchers theorize that BFR

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Joshua T. Slysz and Jamie F. Burr

Participated in a 6-Week Study to Examine the Effects of Combining Blood Flow Restriction With Low-Intensity Neuromuscular Electrical Stimulation on Skeletal Muscle Adaptation Age, y Height, cm Weight, kg BMI, kg/m 2 Overall 24 (6) 174 (10) 77 (17) 23 (3) Range 18–45 158–192 50–109 20–30 Males 22 (2) 182 (5

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Alon Eliakim

In recent years there has been a remarkable enhancement in the knowledge and understanding of endocrine responses to exercise and exercise training in children and adolescents who participate in sports. This includes, for example, exercise-associated changes in growth factors that regulate muscle adaptations to exercise training, the use of hormonal changes to assess training intensity, as well as deleterious effects of competitive sports, in particularly if associated with inadequate nutrition, on growth and the reproductive system. However, major scientific gaps still exist in our understanding of the application and translation of this knowledge to the everyday use of young athletes and their coaches. These gaps include the translation of laboratory research to “real-life” training setting to optimize training efficiency, mainly due to the lack of “real-life” exercise studies; and the use of genetic endocrinology for sports selection, the prediction of excellence in sports and to improve training.

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Steven A. Hawkins, Robert A. Wiswell and E. Todd Schroeder

This study examined the relationships between high-intensity resistance exercise and bone mass in postmenopausal women and serum reproductive-hormone levels and bone-mass changes in response to resistance exercise. Women 45–65 years old were assigned to an exercise or a control group. They trained 3 times weekly for 18 weeks at 90,70, and 80% of their 1-RM. Groups were not different in age, height, body mass, muscle strength, or lean body mass. Initial muscle strength increased significantly in the training group. Total hip and intertrochanter bone-mineral density (BMD) increased in the training group. Estradiol, testosterone, osteocalcin, and CrossLaps concentration did not change in either group. Serum estradiol was significantly related to change in BMD at the hip, femoral neck, and intertrochanter, as well as change in lean mass. Results suggest that high-intensity resistance exercise can increase BMD of the hip and that serum estrogen concentrations might influence bone and muscle adaptations to resistance exercise in postmenopausal women.