The control of skeletal muscle relies on a complex integration between descending central input and information that originates from receptors that lie within peripheral tissue. The following investigations were performed to contribute to our understanding of this control. Study 1 ( Chapter 2 ) was designed to determine ( using the H - reflex ) if muscle spindle feedback is similar in the gastrocnemius and soleus. The strength of the H - reflex at rest and during contraction was compared between muscles. The results showed that the maximal H - reflex obtained at any level of contraction is larger in the soleus than in the gastrocnemius. We argue that along with the muscles having different structures and functions, the recruitment capabilities of their motoneurons are quite different. We also found that the maximal M - wave, which has for years been thought to be a consistent measure of maximal muscle activity, was quite variable within subjects during different conditions. Review of the maximal M - wave literature showed evidence that variability in this response did exist between conditions, but that the variability was rarely seen in pooled data, and was therefore not often reported. Study 2 ( Chapter 3 ) was developed to determine if experimental recording techniques, or analysis methods, could affect the magnitude of the maximal M - wave within subjects. The first finding of this study showed that the two most commonly used analysis methods ( peak - to - peak amplitude and area ) provided comparable results, and could not account for the differences seen in the maximal M - wave magnitude. The study did however suggest that the orientation of surface recording electrodes can significantly alter the recorded signal. We argue that although bipolar surface recording is considered superior to monopolar recording in its ability to record a clean signal, it has a large limiting factor, which we call " signal cancellation ". The third study ( Chapter 4 ) focused on the variability in M - wave strength in the gastrocnemius and soleus during a variety of ankle orientations and voluntary contraction levels. This study supported our previous work, and showed that when monopolar recording is used, consistent and significant differences exist in the strength on the M - wave obtained during different conditions that were not seen in bipolar recordings. It was concluded that the difference in maximal M - wave strength obtained during different muscle conditions may be related to a change in the recording electrode to muscle bulk relationship. This finding is important as M - wave strength is consistently used as a normalisation factor in reflex studies, and therefore variability in this measure may seriously affect the results obtained during muscle reflex investigations. The final study ( chapter 5 ) considered the size of the H - reflex, the level of background muscle activity, and the subjects ' weight distribution, during painful and non - painful conditions. We determined that these factors were not modified by pain induced in either agonist or antagonist muscles. The final chapter outlines the major findings from this work, highlights limitations to the research conducted using the H - reflex, and makes suggestions for future research in this area. / Thesis (Ph.D.)--School of Molecular and Biomedical Science, 2006.

Heart-type fatty acid binding protein (H-FABP) is a major fatty acid binding factor in skeletal muscles. Genetic lack of H-FABP severely impairs the esterification and oxidation of exogenous fatty acids in soleus muscles isolated from chow-fed mice (CHOW-solei) and high fat diet-fed mice (HFD-solei), and prevents the HFD-induced accumulation of muscle triglycerides. Here, we examined the impact of H-FABP deficiency on the relationship between fatty acid utilization and glucose oxidation. Glucose oxidation was measured in isolated soleus muscles in the presence or absence of 1 mM palmitate (simple protocol) or in the absence of fatty acid after preincubation with 1 mM palmitate (complex protocol). With the simple protocol, the mutation slightly reduced glucose oxidation in CHOW-muscles, but markedly increased it in HFDmuscles; unexpectedly, this pattern was not altered by the addition of palmitate, which reduced glucose oxidation in both CHOW- and HFD-solei irrespective of the mutation. In the complex protocol, the mutation first inhibited the synthesis and accumulation of triglycerides and then their mobilization; with this protocol, the mutation increased glucose oxidation in both CHOW- and HFD-solei. We conclude: (i) H-FABP mediates a non-acute inhibition of muscle glucose oxidation by fatty acids, likely by enabling both the accumulation and mobilidoes not mediate the acute inhibitory effect of extracellular fatty acids on muscle glucose oxidation; (iii) H-FABP affects muscle glucose oxidation in opposing ways, with inhibition prevailing at high muscle triglyceride contents.zation of a critical mass of muscle triglycerides; (ii) H-FABP

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Title: Viscousand elastic properties of soft tissue"in situ" Goals and methods: The aim of this thesis is to measure the viscoelastic properties of human soleus muscle and Achilles tendonin vivo and post mortem in situ. It is a pilot study that uses myotonometry as the method of measurement. Based on the response of connective tissues on deformation made by tip of myotonometer, resp. its viscoelastic properties, curves in graphsare created. Three main described parameters of thecurveare steepness, deflection and its surface area. Main goal of the experiment is to compare properties of different types of tissue and their potential differences while denervated or innervated. Results of this study may help with better understanding of the soft tissues behavior in response to manual therapeutic contact. The study also describes the differences between in vivo and post mortem tissue properties that may be help further studies which use post mortem tissues to predict in vivo behavior. Results: Soft tissues in vivo have higher viscosity. In comparison, post mortem tissues have significantly higher stiffness and energy dissipation than in vivo. Elasticproperties of denervated soft tissue manifest with approx. 7 secondsdelay. Viscoelastic properties of muscle tissueshow changes depending on deeper...

Aim The purpose of this study was to compare resistance-trained (RT) and non-trained (NT) males regarding mechanisms for neural activation during isometric muscle contractions of the soleus muscle. Further the plantar flexor strength of the two groups were compared. Method Ten males that had been resistance training for at least 3 years (RT) and 10 who did not train regularly (NT) participated in the study. The participants performed isometric contractions of their right plantar flexors against an isokinetic dynamometer at 15, 25, 50, 80 and 100% of maximal voluntary contraction. Five contractions were performed for each level in two different conditions; one where the participants were stimulated using transcranial magnetic stimulation over the left motor cortex and one in which they were stimulated electrically over the tibial nerve. Stimulations were also delivered at rest. The resulting soleus muscle motor evoked potentials (MEPs) and V-waves were normalized to a maximal M-wave (Mmax). Plantar flexor strength was measured and voluntary activation estimated using the twitch interpolation technique. Results No significant difference was found between the RT and the NT group for voluntary activation, V/Mmax ratio or MEP/Mmax at any level of maximal voluntary contraction (MVC). The RT group was significantly stronger than the NT group. Conclusions The study showed that the RT group was stronger than the NT group. Despite the difference in strength there was no significant group difference between the two groups in MEPs, V/Mmax or voluntary activation. This indicates that there is no, or a very small difference in corticospinal excitability of the soleus muscle between the chronic RT males and the NT males.

Title: The effect of yogic relaxation on muscle tone Objectives: The aim of this thesis is to present a technique of yogic relaxation, yoga nidra, as one of the possible methods for releasing mental and physical tension. The aim of the practical part of this thesis is to evaluate the effect of yoga nidra on muscle tone. Methods: The practical part of this thesis is a pilot study with six participants. For objective assessment of muscle tone the method of myotonometry was used. M. soleus was selected as the muscle to be measured. First, the original muscle tone of m. soleus on the dominant lower limb of the participants was measured. Then the group of participants was instructed about the practice of yoga nidra and was asked to practice it every day in the following 14 days at home using a given audio recording. After the two-week training, the muscle tone of m. soleus was measured again in order to determine the long-term effect of yoga nidra on muscle tone. Finally, the participants participated in a group lesson of yoga nidra guided by a yoga teacher. Then, the muscle tone of m. soleus was measured again in order to determine the instant effect of yoga nidra on muscle tone. Results: After the two-week training of yoga nidra the research found a decrease in muscle tone of m. soleus in 5 out of 6...

Title: The influence of skating frequency on muscle tone of musculus triceps surae. Objective: The aim of this master degree thesis is to determine whether and how much influence the frequency and intensity of isotonic load the muscle tone of musculus soleus during skating of a professional ice hockey player. The muscle tone of musculus soleus is the most objectively measured part of musculus triceps surae by myotonometer. Methods: The master degree thesis is divided into the theoretical part, the processed form of research that serves as a basis for investigation in the second, empirical part. Change in muscle tone of musculus soleus was investigated by using myotonometer, which followed after a full physiotherapy examination. It is quantitative research using quasi-experimental study. Measurements were performed on 10 subjects - professional ice hockey players who are fully manage the technique of skating on the ice, before load, after low frequency isotonic load and after high frequency isotonic load. Conclusion: The myotonometric measurements revealed that after low and high frequency isotonic load of skating on ice rink, the muscle tone of musculus soleus is the same or slightly lower than before load. Keywords: Muscle tone, myotonometer, musculus soleus, skating, ice hockey

Title: The influence of skating frequency on muscle tone of musculus triceps surae. Objective: The aim of this master degree thesis is to determine whether and how much influence the frequency and intensity of isotonic load the muscle tone of musculus soleus during skating of a professional ice hockey player. The muscle tone of musculus soleus is the most objectively measured part of musculus triceps surae by myotonometer. Summary: The master degree thesis is divided into the theoretical part, the processed form of research that serves as a basis for investigation in the second, empirical part. Change in muscle tone of musculus soleus will be investigated by using myotonometer, which will follow after a full physiotherapy examination. Measurements will be performed on 10 subjects - professional ice hockey players who are fully manage the technique of skating on the ice, before load, after low frequency isotonic load and after high frequency isotonic load. Conclusion: The myotonometric measurements revealed that after low and high frequency isotonic load of skating on ice rink, the muscle tone of musculus soleus is the same or slightly lower than before load. Keywords: Muscle tone, myotonometer, musculus soleus, skating, ice hockey

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