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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Caracterização do torque externo a partir das características músculo-esqueléticas dos flexores do cotovelo

Silva, Fábio Canto da January 2007 (has links)
Atualmente são utilizados diversos equipamentos e implementos para treinamento de força. Os flexores do cotovelo apresentam enorme variedade de exercícios, cada qual apresentando diferentes características de torque externo. Na maioria dos casos, a escolha dessa característica aparenta não seguir nenhum critério pré-estabelecido para sua determinação, sendo que a variação desse torque externo é fator causador de grande influência na adaptação do músculo ao treinamento imposto. Com isso, a escolha de um exercício demanda conhecimento dos objetivos de treino, além do conhecimento das características musculares, no que diz respeito à possibilidade de produção de força e torque musculares. Esse estudo objetivou verificar o comportamento do torque muscular de flexão do cotovelo de indivíduos ativos e sedentários, comparando-os com a característica de torque externo de quatro exercícios usuais de flexão do cotovelo (Rosca Direta, Rosca Scott, Rosca Banco Inclinado e Rosca Polia). Além disso, visou-se comparar a capacidade de produção de torque entre as três posições da articulação rádio-ulnar. Assim, foi avaliado o torque concêntrico máximo de flexão do cotovelo, numa velocidade de 45º/s, num dinamômetro isocinético. A amostra contou com 20 universitários jovens e saudáveis, divididos nos dois grupos. As relações torque-ângulo encontradas para o grupo de ativos não apresentaram pico de torque e, sim, um platô que se prolonga por grande parte da relação. As relações torqueângulo encontradas para o grupo de sedentários apresentam um pico definido, ocorrendo, em média, entre 32º e 43º de flexão do cotovelo, porém com grande variabilidade. Não foram encontradas diferenças estatisticamente significativas entre as posições da articulação rádioulnar com relação à: ângulo de pico, taxa de acréscimo, taxa de decréscimo, torque final (sedentários) e torque absoluto. Apenas o grupo de ativos apresentou diferenças significativas entre as posições com relação ao torque final. Não foram encontradas diferenças estatisticamente significativas entre os grupos com relação à: taxa de acréscimo e torque final. Houve diferenças significativas entre os grupos com relação à taxa de decréscimo, em todas as posições da articulação rádio-ulnar. Nenhum dos exercícios avaliados parece apresentar uma característica de torque externo condizente com quaisquer relações torque-ângulo encontradas nesse estudo. Assim, foi sugerida uma polia assimétrica, com raio variando de acordo com as taxas de variação média de torque encontradas na amostra, produzindo, assim, um torque externo que acompanha as características de produção de torque muscular. Nesse estudo, foi possível concluir que existe grande variabilidade com relação às variáveis inerentes às características de produção máxima de torque flexor do cotovelo. Assim, é possível que se faça inferências com relação à adaptação funcional obtida com o treinamento, o qual levaria a musculatura a apresentar um pico de torque mais bem definido e próximo aos 90º de flexão do cotovelo. Por outro lado, o sedentarismo faria com que o ângulo de maior produção de torque muscular se aproxime da extensão do cotovelo, numa característica de produção de força condizente com o trecho ascendente da relação forçacomprimento, atuando num ciclo alongamento-encurtamento. / Nowadays there are many types of equipment used to strength training. Especially the elbow flexors present great variety of exercises, each one with different resistance moment characteristics. In the majority of the cases, this characteristic of resistance moment does not seem to follow any criterion for its determination and its variation is a causing factor of great influence in the muscle adaptation to the imposed training. Thus, the exercise choice demands to know the objectives of the training and muscle characteristics, in respect to the possibility of muscle force and moment production. This aim of this study was to verify the elbow flexor muscle moment profile of actives and sedentary subjects, comparing it with resistance moment characteristics of four usual exercises of elbow flexion (Barbell Biceps Curl, Scott Biceps Curl, Lying Dumbbell Curl and Standing Cable Curl). Moreover, it was aimed to compare the moment production capacity between three forearm positions. Thus, it was measured maximal concentric elbow flexion moment, at 45º/s, on an isokinetic dynamometer. The sample was composed by 20 young and healthy students, divided in two groups. The moment-angle relationship founded in the active group did not show a moment peak, but a plateau that prolongs for great part of the relationship. The moment-angle relationship founded in the sedentary group showed a defined peak, occurring, on average, between 32º and 43º of elbow flexion, however with great variability. It was not founded statistic differences between forearm positions in relation to: moment peak angle, moment increase rate, moment decrease rate, final moment (sedentary) and absolute moment. Only the active group shown statistic differences between positions in relation to final moment. It was not founded statistic differences between groups in relation to: moment increase rate and final moment. There was statistic difference between groups in relation to moment decrease rate, in all forearm positions. None of the evaluated exercises seems to show an external moment characteristic suitable with any moment-angle relationship founded on this study. Thus, it was suggested an asymmetrical pulley, whose radius variation fit well with increase and decrease rates founded at this sample, producing, in this way, an external moment suitable with the capacity of muscle moment production. In this study, it was possible to conclude that occur great variability in respect to the variables inherent to the characteristics of maximal elbow moment flexion production. Thus, it was possible to infer in relation to functional adaptation gotten with the training, which would lead the muscle to present a most defined moment peak and closer to 90º of elbow flexion. Nevertheless, the sedentary would lead the moment peak angle closer to elbow extension, which force production characteristic would be suitable with the ascending limb of force-length relationship, undergoing a stretch-shortening cycle.
62

Osteochondritis dissecans of the humeral capitellum: treatment options and differential indications

Hennrikus, William Patrick 12 March 2016 (has links)
INTRODUCTION: Osteochondritis dissecans (OCD) of the capitellum is a focal condition affecting the articular cartilage and subchondral bone, typically in adolescent athletes. Limited data exists regarding the indications and expected outcomes of the various treatment methods of capitellar OCD, and the optimal treatment strategy remains controversial. Risks of progressive capitellar OCD include osteoarthritic changes and permanent elbow disability. STUDY AIMS: The objective of this literature review is to assess the data and the conclusions to be drawn from the existing literature on the differential indications for the various treatment options for capitellar OCD, using low-level meta-analysis and qualitative observations, to suggest a course of future study with the purpose of clarifying the differential treatment indications and improving the care of capitellar OCD patients. The most recent 10 years (2004-2014) of data are the focus, in order to evaluate the most modern indications, surgical techniques, surgical skills, and clinical outcomes. DISCUSSION OF PUBLISHED DATA: Ultrasound reportedly offers a high predictive value for screening baseball players for capitellar OCD, although sensitivity, specificity, and cost-effectiveness are unknown. Plain radiographs and magnetic resonance imaging (MRI) are useful diagnostic resources for making the decision to operate, but their sensitivities and specificities are imperfect. Evidence suggest that early stage OCD in physically immature patients may recover with non-operative management, while advanced stage OCD in older patients will likely achieve a better recovery with operative management. Risk factors for poor outcomes following surgical management of capitellar OCD may reportedly include patient age, physical maturity, athletic competition level, large lesion diameter and thickness, and lateral lesion location. The advantages of removal, debridement, and marrow stimulation techniques include the minimal invasiveness associated with arthroscopy. Successful fragment fixation can preserve normal articular properties, but may risk implant complications and secondary surgeries. Mosaicplasty is frequently suggested when patient or lesion characteristics seem to preclude other surgical methods, or when prior surgical treatment attempts fail, but disadvantages of mosaicplasty include the technical complexity of the procedure and the risk of donor site morbidity. CONCLUSIONS: The capitellar OCD literature has accumulated a wealth of level IV case series reporting generally satisfactory short-term results of the various surgical options. There is little need for more descriptive literature on this topic at this time. Modern treatment strategies are incomplete and poorly defined, based upon the suggestions of small case series offering disorganized, low-quality data. A study of the cost-effectiveness of ultrasound screening in high-risk athletes would be useful. A large, comparative case-control study or prospective cohort study of higher methodological quality and better standardization is needed to advance the knowledge on this topic, and classification and regression tree analysis could be applied meaningfully. With more organized data and analysis, it will become easier to take a systematic approach to treating capitellar OCD, settle clinical controversy and improve patient outcomes.
63

Contribution of the anconeus muscle to the elbow kinematics : range of motion of 90° of flexion-extension and pronation-supination

Miguel Andres, Israel January 2016 (has links)
The anconeus, a small triangular muscle positioned on the posterolateral part of the elbow joint, has been the subject of considerable research without a satisfactory conclusion being reached regarding the role it plays during normal elbow kinematics. The aim of this investigation was to elucidate the function of the anconeus muscle and find the relative contribution that it makes to elbow kinematics by examining relative electrical muscle activity and elbow kinematics both before and after anconeus defunctioning carried out using a local anaesthetic (lidocaine). The study was performed through an examination of the myoelectric activity of the representative elbow flexor and extensor muscles (biceps brachii and triceps brachii) and the elbow kinematics and kinetics. Right-handed, healthy volunteers performed elbow flexion-extension and supination-pronation movements in both horizontal and sagittal planes before and after blocking of the anconeus. The kinematics and kinetics of the elbow were assessed using inertial sensors, and muscle electrical activity was recorded using surface electromyography. In the following stage of the study, the anconeus muscle was blocked through an injection of lidocaine and then the flexion-extension and pronation-supination movements were repeated. The relative electrical activity results from the anconeus before blocking clearly indicate that the activity of the muscle was higher during the extension portion of the flexion-extension cycle, suggesting that it behaves as an extensor muscle. However, from the paired sample t-test analysis, it was found that blocking of the anconeus had no effect on the kinematics and kinetics of the elbow, including the angular velocity, net torque, power and net joint work. Moreover, the angular velocity data for the elbow, before and after the blocking for all movements, showed a linear trend with slopes and Pearson's correlations close to unity, indicating no apparent difference on the elbow kinematics. In addition, the relative electrical activity of the biceps and triceps brachii muscles did not alter significantly following blocking of the anconeus. These findings suggest that the anconeus muscle is a relatively weak elbow extensor as it is likely that the small contribution that the anconeus provides during extension before blocking is compensated by the triceps brachii after the anconeus is deactivated. In order to provide additional weight and support to the findings of the experimental study, a computational model of the elbow joint was created in Abaqus CAE with the aim of investigating the contribution of the anconeus during the flexion-extension motion. In particular, the effect on the range of motion and contact area of the elbow joint was investigated both before and after anconeus blocking. The analysis was done in a range of motion of 90°, starting with the elbow extended 30° and ending flexed 120°. The elbow joint model considered cortical bone, trabecular bone, cartilage, collateral ligaments, the anconeus, biceps brachii and triceps brachii. The results of the investigation indicated that the anconeus muscle does not produce a significant change in the range of motion and contact area in the articulation, an outcome that supports the findings of the experimental investigation.
64

Caracterização do torque externo a partir das características músculo-esqueléticas dos flexores do cotovelo

Silva, Fábio Canto da January 2007 (has links)
Atualmente são utilizados diversos equipamentos e implementos para treinamento de força. Os flexores do cotovelo apresentam enorme variedade de exercícios, cada qual apresentando diferentes características de torque externo. Na maioria dos casos, a escolha dessa característica aparenta não seguir nenhum critério pré-estabelecido para sua determinação, sendo que a variação desse torque externo é fator causador de grande influência na adaptação do músculo ao treinamento imposto. Com isso, a escolha de um exercício demanda conhecimento dos objetivos de treino, além do conhecimento das características musculares, no que diz respeito à possibilidade de produção de força e torque musculares. Esse estudo objetivou verificar o comportamento do torque muscular de flexão do cotovelo de indivíduos ativos e sedentários, comparando-os com a característica de torque externo de quatro exercícios usuais de flexão do cotovelo (Rosca Direta, Rosca Scott, Rosca Banco Inclinado e Rosca Polia). Além disso, visou-se comparar a capacidade de produção de torque entre as três posições da articulação rádio-ulnar. Assim, foi avaliado o torque concêntrico máximo de flexão do cotovelo, numa velocidade de 45º/s, num dinamômetro isocinético. A amostra contou com 20 universitários jovens e saudáveis, divididos nos dois grupos. As relações torque-ângulo encontradas para o grupo de ativos não apresentaram pico de torque e, sim, um platô que se prolonga por grande parte da relação. As relações torqueângulo encontradas para o grupo de sedentários apresentam um pico definido, ocorrendo, em média, entre 32º e 43º de flexão do cotovelo, porém com grande variabilidade. Não foram encontradas diferenças estatisticamente significativas entre as posições da articulação rádioulnar com relação à: ângulo de pico, taxa de acréscimo, taxa de decréscimo, torque final (sedentários) e torque absoluto. Apenas o grupo de ativos apresentou diferenças significativas entre as posições com relação ao torque final. Não foram encontradas diferenças estatisticamente significativas entre os grupos com relação à: taxa de acréscimo e torque final. Houve diferenças significativas entre os grupos com relação à taxa de decréscimo, em todas as posições da articulação rádio-ulnar. Nenhum dos exercícios avaliados parece apresentar uma característica de torque externo condizente com quaisquer relações torque-ângulo encontradas nesse estudo. Assim, foi sugerida uma polia assimétrica, com raio variando de acordo com as taxas de variação média de torque encontradas na amostra, produzindo, assim, um torque externo que acompanha as características de produção de torque muscular. Nesse estudo, foi possível concluir que existe grande variabilidade com relação às variáveis inerentes às características de produção máxima de torque flexor do cotovelo. Assim, é possível que se faça inferências com relação à adaptação funcional obtida com o treinamento, o qual levaria a musculatura a apresentar um pico de torque mais bem definido e próximo aos 90º de flexão do cotovelo. Por outro lado, o sedentarismo faria com que o ângulo de maior produção de torque muscular se aproxime da extensão do cotovelo, numa característica de produção de força condizente com o trecho ascendente da relação forçacomprimento, atuando num ciclo alongamento-encurtamento. / Nowadays there are many types of equipment used to strength training. Especially the elbow flexors present great variety of exercises, each one with different resistance moment characteristics. In the majority of the cases, this characteristic of resistance moment does not seem to follow any criterion for its determination and its variation is a causing factor of great influence in the muscle adaptation to the imposed training. Thus, the exercise choice demands to know the objectives of the training and muscle characteristics, in respect to the possibility of muscle force and moment production. This aim of this study was to verify the elbow flexor muscle moment profile of actives and sedentary subjects, comparing it with resistance moment characteristics of four usual exercises of elbow flexion (Barbell Biceps Curl, Scott Biceps Curl, Lying Dumbbell Curl and Standing Cable Curl). Moreover, it was aimed to compare the moment production capacity between three forearm positions. Thus, it was measured maximal concentric elbow flexion moment, at 45º/s, on an isokinetic dynamometer. The sample was composed by 20 young and healthy students, divided in two groups. The moment-angle relationship founded in the active group did not show a moment peak, but a plateau that prolongs for great part of the relationship. The moment-angle relationship founded in the sedentary group showed a defined peak, occurring, on average, between 32º and 43º of elbow flexion, however with great variability. It was not founded statistic differences between forearm positions in relation to: moment peak angle, moment increase rate, moment decrease rate, final moment (sedentary) and absolute moment. Only the active group shown statistic differences between positions in relation to final moment. It was not founded statistic differences between groups in relation to: moment increase rate and final moment. There was statistic difference between groups in relation to moment decrease rate, in all forearm positions. None of the evaluated exercises seems to show an external moment characteristic suitable with any moment-angle relationship founded on this study. Thus, it was suggested an asymmetrical pulley, whose radius variation fit well with increase and decrease rates founded at this sample, producing, in this way, an external moment suitable with the capacity of muscle moment production. In this study, it was possible to conclude that occur great variability in respect to the variables inherent to the characteristics of maximal elbow moment flexion production. Thus, it was possible to infer in relation to functional adaptation gotten with the training, which would lead the muscle to present a most defined moment peak and closer to 90º of elbow flexion. Nevertheless, the sedentary would lead the moment peak angle closer to elbow extension, which force production characteristic would be suitable with the ascending limb of force-length relationship, undergoing a stretch-shortening cycle.
65

Effekten av excentrisk träning vid epikondyalgi-en systematisk litteraturstudie / The effect of eccentric training for patients with epicondylalgia-a systematic review

Niemelä, Jonna January 2020 (has links)
Bakgrund: Tendinopati är en vanlig diagnos hos patienter inom primärvården, en av de vanligare formerna av tendinopati är epikondyalgi. Det är oklart vad som är den mest effektiva behandlingen för epikondyalgi. Studier har visat lovande resultat av enbart excentrisk träning (ET) samt som del av kombinationsbehandling. Det var därför relevant att kartlägga vilken effekt excentrisk träning har vid epikondyalgi. Syfte: Kartlägga och sammanställa aktuell forskning gällande evidensen för effekten av  ET på smärta och funktion vid epikondyalgi. Metod: En systematisk litteraturstudie. Litteratursökning genomfördes i databaserna PubMed, Cinahl, Web of Science samt Scopus. Åtta artiklar inkluderades. Dessa kvalitétsgranskades enligt PEDro, varefter den sammanvägda evidensen bedömdes enligt GRADE.  Resultat: De inkluderade studiernas kvalité enligt PEDro varierade från medelhög till hög. Begränsat vetenskapligt underlag för att ET inte minskar smärta vid lateral epikondyalgi (LE). Otillräckligt vetenskapligt underlag för att ET ökar funktion vid LE. Otillräckligt vetenskapligt underlag för en jämförelse av ET i olika former eller som del av kombinationsbehandling. Inga resultat för medial epikondyalgi framkom. Slutsats: ET har inte någon effekt på smärta vid LE. Det finns otillräcklig vetenskaplig grund för effekten på funktion vid LE. Interventionerna, i studierna som jämförde ET i olika former eller utvärderade kombinationsbehandlingar, skilde sig åt vilket gjorde att sammanvägningen av dessa resultat inte var möjlig. Vidare forskning behövs för att kunna fastställa effekterna av excentrisk träning vid epikondyalgi. / Background: Tendinopathy is a common diagnosis in primary care, a common form of tendinopathy is epicondylalgia. However, the most effective treatment for epicondylalgia is undetermined. Studies have shown promising results in regard to eccentric training (ET) as a stand-alone treatment as well as adjunct to other treatments. It is therefore relevant to map the effect of ET for patients with epicondylalgia. Objective: Map and compile current evidence on the effect of ET on pain and function for patients with epicondylalgia. Methods: A systematic review. A search was conducted in the PubMed, Cinahl, Web of Science and Scopus database. Eight articles were included. These were assessed for quality according to the PEDro scale and the evidence was assessed according to GRADE. Results: The quality of the included studies ranged from medium to high. Limited evidence showed that ET does not reduce pain for patients with lateral epicondylalgia, LE. Insufficient evidence showed that ET improves function. The evidence on the comparison of ET in different forms or in combination with other treatments was insufficient. No results emerged for medial epicondylalgia. Conclusion: ET does not reduce pain for patients with LE. There is insufficient evidence on the effect of ET on function for patients with LE. Studies comparing different forms of ET alone or in combination with other treatments have used different interventions, preventing the aggregation of results. Further research is needed to determine the effects of ET for patient with epicondylalgia.
66

Coordination of multiple muscles in two degree of freedom elbow movements

Sergio, Lauren E. (Lauren Elisabeth) January 1994 (has links)
No description available.
67

Kinematic and passive resistive properties of human shoulder hip and elbow complexes /

Chen, Shuenn-muh January 1986 (has links)
No description available.
68

Effects of Velocity on Work Production about the Human Elbow Joint During Stretch-Shortening and Non-Stretch-Shortening Tasks

Benoit, Daniel January 1997 (has links)
<p> The performance enhancement of stretch shortening cycle (SSe) contractions has been well documented in the literature. However, the majority of these studies have been performed either on gross human systems for multijointed movements, or in isolated animal muscle studies using in-vitro preparations. This study was designed to apply the principles used for these invitro animal studies to the human system, under conditions that would allow results to be directly associated with a specific muscle or muscle group. Previous investigations by Lynch (1992) and Benoit and Dowling (1995) have supported the use of muscle models to predict elbow flexor torque and sse performance enhancement. The purpose of this study was to use an EMG based muscle model to investigate the possible relationship between sse tasks at different frequencies of elbow flexion-extension and performance enhancement of the elbow flexor muscles. </p> <p> A Hill based muscle model was used to predict elbow flexor torque of seven healthy male subjects (23-40 years of age) under voluntary and stimulated contraction conditions. EMG of the elbow flexors and extensors was recorded from the biceps brachii and triceps respectively. Elbow flexor stimulation was done transcutaneously with a voltage equivalent to a 60% MVe torque; stimulation lasted four seconds at a frequency of 50 Hz. A simulated constant muscle activation torque was also derived from the muscle model for all trials. Externally measured torque was measured using a strain gauge located on a shaft situated along the axis of rotation of the elbow joint. A torque motor was used to drive the forearm (fastened to a manipulandum) at four frequencies of elbow flexion-extension (.58, 1.5, 2.4, and 3.3 Hz) over a range of 162 to 105 degrees of elbow extension. Non-SSe trials were performed at these same velocities and over the same range of motion. Torque was then integrated as a function of joint angle displacement to yield the work produced about the elbow. Passive work was subtracted from all trials. </p> <p> The results indicate that a significant increase in muscle work followed sse tasks as opposed to non-SSe tasks and this increased work was relatively highest at 2.4 Hz. Work about the elbow decreased with increasing frequency of movement for both sse and non-sse conditions. The simulated constant activation muscle model predicted work well for all trials and conditions, indicating muscle model accuracy. The EMG driven model predicted well for all non-SSe trials but significantly underestimated the work for sse tasks, suggesting a decrease in myoelectric activity. This decrease was evidenced by a decrease in average M-wave amplitude with increasing SSe velocity. This study indicates that the contractile component is directly involved in optimizing muscle work during sse tasks and that the performance enhancement of sse tasks may take place at the myofilament and cross-bridge level. </p> / Thesis / Master of Science (MSc)
69

Changes in Skeletal Muscle Ultrastructure and Strength Performance following acute resistance exercise

Gibala, Martin J. 11 1900 (has links)
The purpose of this study was to examine changes in muscle ultrastructure and strength performance following a single bout of elbow flexor resistance exercise. Eight untrained males performed 8 sets of 8 repetitions at 80% concentric 1 RM. One arm performed only the concentric (CON) phase of the movement while the other performed only the eccentric (ECC) phase. Maximum isometric (MVC), low (LV} and high velocity (HV} concentric peak torque, and evoked contractile property measurements of the elbow flexors were made before and after the bout, and at 24, 48, 72 and 96 h. Needle biopsies were obtained from the biceps brachii prior to the exercise, immediately post-exercise from each arm (POSTCON, POST-ECC}, and 48 h post-exercise from each arm (48H-CON, 48H-ECC). Electron microscopy was used to quantify the extent of fiber disruption in each sample. The severity of disruption was classified as focal (FOC}, moderate (MOD}, or extreme (EXT}. All strength measurements decreased (P s; o. 05} below pre-exercise values immediately post-ex in both arms, but dramatic differences were observed between arms during the subsequent recovery period. MVC, LV, HV and peak twitch torque (PTT) recovered to pre-ex values by 24 h in the CON arm. In the ECC arm, HV did not recover for at least 72 h, and MVC, LV and PTT remained depressed at 96 h. ANOVA revealed a greater (P s; 0.05) number fibers were disrupted in the POST-CON, POST-ECC, 48H-CON and 48H-ECC samples compared to BASE. Significantly more fibers appeared disrupted in the POST-ECC (82%) and 48H-ECC (80%) samples compared to the POSTCON (33%) and 48H-CON (37%) samples, respectively. In addition, the POST-ECC (41%) and 48H-ECC (50%) samples contained a greater number of fibers with EXT disruption compared to the POST-CON (13%) and 48H-CON (17%) samples. Decreases in MVC at 48 h correlated (P ~ 0.05) with the extent of EXT disruption in the 48H-CON and 48H-ECC samples. These data indicate that both the CON and ECC phase of weightlifting produce myofibrillar disruption, with the greatest disruption occurring during the ECC phase. This study was supported by the Natural Sciences and Engineering Research Council of Canada. / Thesis / Master of Science (MSc)
70

Ballistic Elbow Extension Actions in Karate-Trained and Control Subjects: Agonist Premovement Depression (PMD) and Movement Performance / Ballistic Elbow Extension Actions in Karate-Trained and Control Subjects

Zehr, E. Paul 08 1900 (has links)
Ballistic movements have been shown to be controlled differently by the central nervous system than slow, ramp actions. It has been suggested that the cerebellum is involved primarily with ballistic actions, while the basal ganglia primarily control slower movements. These command and control differences have been shown to manifest in unique ways at the neuromuscular level. Ballistic actions evidence high firing rates, brief contraction times, and high rates of force development. A characteristic triphasic agonistantagonist-agonist burst pattern presents itself during ballistic movement, wherein the amount and intensity of antagonist co-activation is variable. In conditions of low-grade tonic muscular activity, a premovement depression (P:MD; or silent period, PMS) can occur in both agonist and antagonist muscles prior to ballistic contraction. The agonist P:MD period may serve to potentiate the force and velocity of the following contraction A selective activation of fast twitch motor units may occur in ballistic contractions under certain movement conditions. Finally, high velocity, ballistic training induces specific neuromuscular adaptations that are representative of the underlying neurophysiological mechanisms that sub serve ballistic movement. / Thesis / Master of Science (MS)

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