Mathematical relationships have long been used to describe many aspects of muscle function such as the relationship between muscle force and muscle length, muscle force and velocity of contraction or the degree of muscle activation during a contraction. During this work various mathematical expressions have been employed in order to gain an insight into different aspects of muscle activity. The first part of the work examined whether performing a strength protocol on a dynamometer can lead to an increase in eccentric strength output as well as in the neuromuscular activation of the quadriceps group of muscles that appears inhibited during slow concentric and fast eccentric contractions. Neuromuscular activation was modelled via a three-parameter sigmoid function that was also tested for robustness to perturbations in the maximum activation values. During the second part of the study the "functional" hamstrings to quadriceps ratio H:Qfun was expressed as a function of two variables i.e., angular velocity and joint angle. Initially nine-parameter torque-angular velocity-angle profiles were obtained for the knee extensors and flexors from a group of participants. A theoretical 17- parameter H:Qfun function was then derived for each dataset. Subsequently, a simpler, 6-parameter function was derived, RE = aexp(bωn + cθm)-dω1/2θ2 that best reproduced the original 17-parameter fit. Finally, a six-segment subject specific torque-driven model of the Snatch lift was developed in order to investigate the optimal mechanics of the lift. The model simulated the lift from its initiation until the end of the second pull when the feet of the athlete momentarily leave the platform. The six-segment model comprised of foot, shank, thigh, torso (head + trunk), arm and forearm segments with torque generators at the ankle, knee, hip and shoulder joints respectively. The torque profiles were obtained using an isokinetic dynamometer.

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京都大学 / 新制・課程博士 / 博士(人間健康科学) / 甲第24810号 / 人健博第116号 / 新制||人健||8(附属図書館) / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 黒木 裕士, 教授 青山 朋樹, 教授 松田 秀一 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DGAM

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Bakgrund: Manuella behandlingstekniker såsom stretching och ledmobilisering används inom veterinärmedicinsk fysisk rehabilitering av hund. Det råder inte konsensus angående vid vilka indikationer som mobilisering och manipulation kan användas med förväntad positiv effekt eller med vilken dosering. Det saknas också evidens för bland annat effekten av stretching av muskulatur på ledrörlighet och smärta hos hund med ospecificerade smärttillstånd i rörelseapparaten. Syfte: Syftet var att undersöka den akuta effekten av statisk stretching av m.iliopsoas och hamstrings på muskellängd, funktion och smärta hos hund med ospecificerad ländryggssmärta. Metod: Studien genomfördes som en Single-Case Experimental Design (SCED). De tre deltagande hundarna med av veterinär diagnostiserad ospecificerad ländryggssmärta rekryterades via författarens verksamhet. Deltagande hundägare utförde interventionen i form av statisk stretching under tre veckor. Datainsamlingen utfördes medelst mätningar av muskellängd två gånger per vecka under baslinje- och interventionsfas samt att hundägarna fick fylla i enkäten Canine Brief Pain Inventory – S (CBPI – S) en gång per vecka. Resultaten presenterades i diagramform och text.  Resultatsammanfattning: Hos en av tre deltagare uppmättes ökad muskellängd och för två av tre deltagare visade resultaten minskad skattad smärtintensitet och ökad skattad funktion. Slutsats: Statisk stretching som intervention för hundar med ospecificerad ländryggssmärta kan i den aktuella studien inte visa på entydig effekt vad gäller förändring av muskellängd, skattad smärtintensitet och skattad funktion. / Background: Manual therapies such as stretching and joint mobilization are used in veterinary physical rehabilitation of dogs. No consensus exists in which indication mobilization and manipulation can be used with expected positive effect or in what dosage. There is a lack of evidence regarding the effects of stretching of musculature on joint mobility and pain in dogs with unspecified pain conditions in the musculoskeletal system. Objective: The aim of this study was to explore the acute effect of static stretching of m.iliopsoas and hamstrings on muscle length, function and pain in dogs with unspecified lower back pain.  Method: This study was conducted as a Single-Case Experimental Design (SCED). The three participating dogs, veterinary diagnosed with unspecified lower back pain, were recruited through the author’s business. The participating dog owners carried out the intervention consisting of static stretching during three weeks. The data collection was conducted by measuring muscle length twice a week during baseline and intervention phases and the participating dog owners filling in the questionnaire Canine Brief Pain Inventory – S (CBPI –S) once a week. The results were presented in diagrams and text. Results: Increased muscle length was measured in one out of three participants and two out of three participants showed reduced estimated pain intensity and increased estimated function. Conclusion: The current study showed no conclusive results regarding the effect of static stretching on muscle length, estimated pain intensity and estimated function in dogs with unspecified lower back pain.

The main aim of this thesis was to examine hamstrings anatomy and its influence on knee flexor muscle function in healthy young men. A secondary aim was to better understand the implications of hamstrings anatomy and function, and their variability, in relation to the risk of strain injury. The functional and conventional H:Q ratios (examined up to high angular velocities) as well as the knee joint angle-specific isometric H:Q ratio exhibited good test-retest reliability at joint positions that closely replicated the conditions of high injury risk. Football players did not exhibit any differences in angle-specific or peak torque H:Q ratios compared to recreationally active controls. Knee extensor and flexor strength, relative to body mass, of footballers and controls was similar for all velocities, except concentric knee flexor strength at 400° s-1 (footballers +40%; P < 0.01). Muscle volume explained 30-71% and 38-58% of the differences between individuals in knee extensors and flexors torque respectively across a range of velocities. A moderate correlation was also found between the volume of these antagonistic muscle groups (R2= 0.41). The relative volume of the knee extensors and flexors explained ~20% of the variance in the isometric H:Q ratio and ~31% in the high velocity functional H:Q ratio. Biceps femoris long head exhibited a balanced myosin heavy chain isoform distribution (47.1% type I and 52.9 % total type II) in young healthy men, while BFlh muscle composition was not related to any measure of knee flexor maximal or explosive strength. Biceps femoris long head proximal aponeurosis area varied considerably between participants (>4-fold) and was not related to biceps femoris long head maximal anatomical cross-sectional area (r= 0.04, P= 0.83). Consequently, the aponeurosis:muscle area ratio exhibited 6-fold variability (range, 0.53 to 3.09; CV= 32.5%). Aponeurosis size was not related to isometric or eccentric knee flexion strength. The findings of this thesis suggest that the main anatomical factor that contributes to knee flexors function in vivo is hamstrings muscle size, while muscle composition and aponeurosis size do not seem to have a significant influence. The high inter-individual variability of the biceps femoris long head proximal aponeurosis size suggests that a disproportionately small aponeurosis may be a risk factor for strain injury. In contrast, biceps femoris long head muscle composition does not seem to explain the high incidence of strain injuries in this muscle. Quadriceps and hamstrings muscle size imbalances contribute to functional imbalances that may predispose to strain injury and correction of any size imbalance may be a useful injury prevention tool. Finally, regular exposure to football training and match-play does not seem to influence the balance of muscle strength around the knee joint.

CHARLES UNIVERSITY IN PRAG Faculty of Physical Educational and Sport Department of Physiotherapy THE INFLUENCE OF THE TRAINING PROGRAM ON MUSCLE ACTIVITY OF LOWER LIMB MUSCLES IN RELATION TO THE RISK FACTORS OF HAMSTRING INJURY AT SOCCER PLAYERS Dissertation thesis Supervisor: Author: Doc. PaedDr. Dagmar Pavlů, CSc. Mgr. Iva Hnátová Consultant: PhDr. Aleš Kaplan, PhD. November 2012 SUMMARY Titel: The influence of the training program on muscle activity of lower limb muscles in relation to the risk factors of hamstring injury at soccer players. Objective: Hamstring strain is a serious injury and requires long-term treatment. Hamstring strain has a high risk of recurence. As a result of this injury is long-term lost of competition and training. Prevention is necessary because of this. The mechanism and etiology of this type of injury is still uncertain and still under discussion. Multifactorial etiology is commonly discussed. In our opinion, the best solution is the training program, which is made on the basis of cooperation the physiotherapists and coaches. The goal of this training program should be primary prevention of injury or reintegration of injured athlete in the training program or the prevention of reccurenc of injury. As the result of this cooperation should be training program with all aspects of...

Syfte: Att undersöka om det finns skillnader i muskelaktivering i lår- och sätesmuskulatur under belastad knäböj då den utförs med fri skivstång på axlarna respektive i Smith-maskin. Ett andra syfte var att undersöka om anteversionsvinklar kan påverka muskelaktiveringen.   Metod: Sexton deltagare utförde fem repetitioner av belastade (motsvarande 100% kroppsvikt) knäböj i två omgångar. En omgång i Smith-maskin och en i en fri bana. Tiden för varje knäböj standardiserades till fyra sekunder. Likaså standardiserades djup och fotposition. Ordningen mellan de två olika konditionerna slumpades. Muskelaktiviteten mättes genom att studiepersonerna bar shorts med insydda elektroder som mätte elektromyografisk aktivitet. Craig’s test användes före utförandet för att mäta anteversionsvinklarna hos deltagarna.  Resultat: När knäböjen utfördes i en Smith-maskin var det en lägre muskelaktivitet i mm. quadriceps jämfört med utförande i en fri bana. Tydligast var skillnaden under knäböjens första tre sekunder. Under andra och tredje sekunden var det även lägre aktivitet i hamstrings. Det var ingen skillnad i aktivitet mellan konditioner i m. gluteus maximus eller mellan studiedeltagare med femoral retroversion och neutral höftledsvinkel i någon av konditionerna.  Slutsats:  Resultaten indikerar att unga vältränade individer har en högre aktivitet i mm. Quadriceps under utförande av en belastad knäböj då den utförs i en fri bana jämfört med Smith-maskin. Även mm. hamstrings tycks aktiveras mer men endast i knäledens mest flekterade läge. Inga slutsatser kunde dras gällande skillnader mellan personer med femoral anteversion och femoral retroversion. Mer forskning behövs i området gällande anteversionsvinklar och dess påverkan på muskelaktivitet.

CHARLES UNIVERSITY IN PRAG Faculty of Physical Educational and Sport Department of Physiotherapy THE INFLUENCE OF THE TRAINING PROGRAM ON MUSCLE ACTIVITY OF LOWER LIMB MUSCLES IN RELATION TO THE RISK FACTORS OF HAMSTRING INJURY AT SOCCER PLAYERS Dissertation thesis Supervisor: Author: Doc. PaedDr. Dagmar Pavlů, CSc. Mgr. Iva Hnátová Consultant: PhDr. Aleš Kaplan, PhD. November 2012 SUMMARY Titel: The influence of the training program on muscle activity of lower limb muscles in relation to the risk factors of hamstring injury at soccer players. Objective: Hamstring strain is a serious injury and requires long-term treatment. Hamstring strain has a high risk of recurence. As a result of this injury is long-term lost of competition and training. Prevention is necessary because of this. The mechanism and etiology of this type of injury is still uncertain and still under discussion. Multifactorial etiology is commonly discussed. In our opinion, the best solution is the training program, which is made on the basis of cooperation the physiotherapists and coaches. The goal of this training program should be primary prevention of injury or reintegration of injured athlete in the training program or the prevention of reccurenc of injury. As the result of this cooperation should be training program with all aspects of...

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