A review of the literature on sodium distribution in muscle has been presented including the evidence for heterogeneous distribution and the possible morphological sites of localization of this sodium. Special attention was paid to influx studies on crustacean muscle. The review reveals that while there is good evidence for a heterogeneous distribution, the morphological sites and their associated concentrations of sodium remain obscure. The experiments described in this thesis were performed on muscle fibers of the giant barnacle Balanus nubilis. Single muscle fibers of Balanus are a unique biological preparation due to their large size and ease of dissection. The major disadvantage to single fiber Balanus preparations is the extent of the extracellular space or cleft system. This cleft system contains approximately half the total fiber sodium in 6% of the fiber volume. The purpose of these experiments was to gain a picture of (22)Na+ entry into these single striated muscle fibers with special emphasis on the role of the extracellular space. A histological study revealed that the cleft system was more extensive than had been reported. From measurements made on light and electron microscope pictures it was concluded that no part of Balanus myoplasm was more than 1 - 2μ from a 0.02μ patent cleft. This study gave a picture of the morphological pathway for (22)Na+ diffusion in the extracellular space. Radioautography and radio isotope counting were two techniques used to examine (22)Na+ exchange between the extracellular space and the myoplasm. Since the extracellular space had a sodium concentration of 10 times the myoplasm, the cleft system should be adequately visualized by radioautography. However, the section thickness (15μ) and the high maximum energy of (22)Na+ (0.540MEV) limited the resolution of the radioautograms to 15 - 17.5μ. This resolution coupled with the extent of the cleft system prevented consistent radioautographic visualization of discrete clefts. Radioautographic analysis of fibers with minimal exposure (0.5 minutes) to (22)Na+ revealed a concentration gradient which could be used to define the extracellular pathway and its diffusion coefficient for Na+. The radius of the fiber cross section was found to be a reasonable approximation of the length of the pathway and the diffusion of (22)Na+ in the extracellular space along the pathway was as rapid as the self diffusion of (22)Na+ in dilute solution. A comparison of fibers that had spent 1.5 minutes in the (22)Na+ bath with similar fibers that had a 0.5 minute sucrose rinse revealed that the 0.5 minute sucrose rinse removed half of the (22)Na+ from the extracellular space. The 1.5 minute fibers and all fibers examined after periods in the (22)Na+ bath revealed a homogenous grain distribution in radioautograms. This data conflicted with the rate of (22)Na+ entry predicted by the 0.5 minute fibers. Inappropriate agitation of the 1.5 minute fibers was responsible for the lack of agreement. A further radioautographic study of (22)Na+ influx with experimental times 5, 20, 60 and 180 minutes was analyzed quantitatively. To substantiate this radioautographic study an influx experiment was done with times 5, 10, 20, 40 and 90 minutes. Each study demonstrated two compartments. An initial rapidly exchanging compartment with a half time of 6 - 10 minutes was identified as the extracellular space. The extracellular space contained approximately half the fiber sodium. Both studies detected a rnyoplasmic influx compartment which was still exchanging when the experiments were terminated. The calculated rate constant for myoplasmic exchange (5.6 x 10(-3)/minute) was in good agreement with the value of Allen and Hinke. In conclusion, a useful technique for the radioautography of soluble substances was developed. Both a morphological and a physiological picture of the pathway for (22)Na+ diffusion in the extracellular space was developed. The size and half time of loading of the extracellular space was verified. The myoplasmic influx component was identified by two methods. From these studies emerges a more comprehensive picture of the extracellular space as a pathway for diffusion in Balanus muscle. The failure to consider this compartment in microinjection or flux studies may result in ambiguous conclusions. / Land and Food Systems, Faculty of / Graduate

Four studies were conducted to assess the use of electrical shock on several parameters of avian muscle that contribute to its ultimate quality. In the preliminary study, the effect of preslaughter electric stunning on the tenderness of broilers processed and handled in a standard commercial manner was assessed. The tenderness of cooked breast muscle samples was evaluated by Kramer single blade shear force values. This evaluation indicated that samples from the electrically stunned birds were significantly more tender than those from the no stun controls (p<0.01). The effects of varying the duration, frequency and voltage of a post-exsanguination stimulatory current on the development of rigor mortis and the postmortem glycolytic rate were investigated in Study One. The pH of muscle homogenates at various postmortem sampling times was used as an index of glycolysis whereas rigor development was monitored by the isometric tension technique. Postmortem glycolysis in Biceps femoris and Pectoral is major samples was accelerated by electrical stimulation, as was the time course of rigor development. Pectoral is major samples from treated carcasses required significantly less time to develop maximum tension than control samples (p<0.05). Although Biceps femoris samples from stimulated carcasses also exhibited decreases in the time required to achieve maximum tension when compared to controls, these differences were not significant. Pectoral is maj or samples from carcasses treated with 70V for 2 minutes at either 40 or 80 pulses/s developed significantly lower tension than control samples (p<0.05). No significant differences due to the voltage or total number of pulses were observed for either the time required to achieve maximum tension or the maximum tension developed. The influence of electrical stimulation on the development of rigor was further examined in Study Two. Rigor development again was monitored by the isometric tension technique and changes in metabolite contents for both muscle types were determined by enzymatic analytical techniques. Electrical stimulation reduced the time required by Biceps femoris and Pectoral is major samples to reach maximum tension but this decrease was only significant for the latter (p<0.05). The amount of isometric tension developed by both muscle types was similarly reduced by electrical stimulation. The initial glycogen and ATP contents of both muscles were reduced by electrical stimulation, as were their ATP contents at subsequent sampling periods. Several correlations between the parameters of isometric tension and metabolite contents were noted and regression equations were developed to express the significant relationships. No significant differences due to electrical stimulation in the rate of isometric tension release were observed, but Pectoralis major samples from stimulated carcasses released their developed tension more rapidly than their respective Biceps femoris samples. In the final study, Study Three, the effect of electrical stimulation on muscle proteolytic activity was assessed by two analytical methods for TCA soluble material. In addition, changes in protein extractability, dispersibility and hydrophobicity were followed in control and treated samples during storage for one day at 2°C. Electrical stimulation significantly reduced the time required to reach maximum tension (p<0.05) and decreased the maximum tension achieved for Pectoralis major and Biceps femoris muscle samples. Pectoralis major samples from treated carcasses again released their developed tension faster than their respective Biceps femoris samples. When the muscle samples were analysed for nonprotein nitrogen, neither measure indicated a significant treatment effect. In a similar manner, neither extractable protein, protein dispersibility nor protein hydrophobicity were affected by electrical stimulation. / Land and Food Systems, Faculty of / Graduate

by So Chi-hung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 155-167). / Abstracts in English and Chinese. / Chapter Chapter 1 --- General Introduction --- p.1 / Chapter Chapter 2 --- Physiological Characteristics of Elite Windsurfers --- p.7 / Abstract --- p.8 / Chapter 2.1 --- Introduction --- p.9 / Chapter 2.2 --- Literature Review --- p.11 / Chapter 2.3 --- Method --- p.20 / Chapter 2.4 --- Result --- p.23 / Chapter 2.5 --- Discussion --- p.25 / Chapter 2.6 --- Conclusion --- p.36 / Chapter Chapter 3 --- An evaluation of a windsurfing pumping simulator for objective assessment of windsurfing pumping performance --- p.37 / Abstract --- p.38 / Chapter 3.1 --- Introduction --- p.39 / Chapter 3.2 --- Method --- p.44 / Chapter 3.3 --- Result --- p.48 / Chapter 3.4 --- Discussion --- p.49 / Chapter 3.5 --- Conclusion --- p.50 / Chapter Chapter 4 --- Kinesiological Analysis of Joints' Movement Pattern in Windsurfing Pumping and Its Change with Muscle Fatigue --- p.52 / Abstract --- p.53 / Chapter 4.1 --- Introduction --- p.55 / Chapter 4.2 --- Literature Review --- p.57 / Chapter 4.3 --- Method --- p.65 / Chapter 4.4 --- Result --- p.72 / Chapter 4.5 --- Discussion --- p.77 / Chapter 4.6 --- Conclusion --- p.82 / Chapter Chapter 5 --- The Use of Electromyography in the Study of Windsurfing Pumping --- p.83 / Abstract --- p.84 / Chapter 5.1 --- Introduction --- p.86 / Chapter 5.2 --- Literature Review --- p.89 / Chapter Part 1. --- Frequency Spectrum Analysis During Repeated Isokinetic Knee Extension and Elbow Flexion --- p.106 / Chapter 5.3 --- Method --- p.106 / Chapter 5.4 --- Result --- p.112 / Chapter 5.5 --- Discussion --- p.129 / Chapter 5.6 --- Conclusion --- p.133 / Chapter Part 2. --- Application of Surface EMG in Assessing Muscle Fatigue Pattern in Repetitive Dynamic Windsurfing Pumping Action --- p.134 / Chapter 5.7 --- Method --- p.134 / Chapter 5.8 --- Result --- p.135 / Chapter 5.9 --- Discussion --- p.145 / Chapter 5.10 --- Conclusion --- p.149 / Chapter Chapter 6 --- Conclusion --- p.151 / Chapter Chapter 7 --- References --- p.155 / Chapter Chapter 8 --- Reference Photos --- p.168 / Chapter Chapter 9 --- Appendix --- p.183

"May 2002." Bibliography: leaves 123-144. Aspects of the control of ventilation and an upper airway dilator muscle (genioglossus) are compared between healthy men and women, in an attempt to identify a gender difference that may contribute to the high male prevalence of sleep apnea.

Exercise induces morphological and metabolic adaptations that are highly specific to the mode of exercise training. These specific phenotypical changes are due to an equally specific molecular response that may depend on the activation and coordination intramuscular signaling pathways. Just as metabolic and morphological changes are influenced by the mode of exercise training, the signaling pathways that mediate exercise adaptation may also be directly related to the training status of skeletal muscle. For example, pre-conditioned skeletal muscle may exhibit a specific intracellular signaling response to an acute bout of exercise that is dependent on past training history. Both Akt (protein kinase B) and extra-cellular signal-related kinase (ERK 1 /2) have been shown to be phosphorylated in response to an acute bout of resistance exercise in human skeletal muscle and have been suggested to mediate the adaptive response to exercise. The purpose of this investigation was to examine the response of Akt and ERKI/2 to an acute bout of resistance exercise in three groups with distinctly different exercise training backgrounds. Twenty one subjects performed 3 sets of 10 repetitions of knee extension exercise at 70% 1-RM. The subjects consisted of a resistance-trained group (RE) (n=7), endurance trained group (END) (n=7) and a sedentary group (SED) (n=7). Muscle biopsies were taken from the vastus lateralis muscle before, immediately after, and 10 min post-exercise and were analyzed for phosphorylation of Akt and ERK1/2. ERK1/2 phosphorylation increased 47%, and 54% from pre-exercise to immediately post-exercise in the SED and RE groups respectively (p < 0.05). ERK1/2 phosphorylation increased 95%, 196%, and 47% from pre-exercise to 10 min post-exercise in the SED, RE, and END groups, respectively. (p < 0.05). The magnitude of ERK1/2 phosphorylation 10 min post-exercise was different between each group and may be linked to the group's training status. (p < 0.05) Akt phosphorylation decreased 42% and 37% from pre-exercise to immediately post-exercise in the SED and END group, respectively (p < 0.05). There was a 40 % increase in Akt phosphorylation from immediate post-exercise to 10 min post-exercise in the END group. In conclusion, training status appears to influence the magnitude and time course of activation of both Akt and ERK1/2 in response to an acute bout of resistance exercise. The immediate response of both ERK1/2 and Akt may play a key role in the adaptive response of skeletal muscle ultimately resulting in metabolic and morphological changes that are dependent on the past training history of the individual. / School of Physical Education, Sport, and Exercise Science

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Little is known about protein profiles in slow-twitch (MHC I) and fast-twitch (MHC IIa and MHC IIx) human skeletal muscle fibers. Therefore we developed a method of assessing fiber type specific protein content across the continuum of human skeletal muscle fiber types. The method presented here combines the advantages of SDS-PAGE for fiber typing with the common Western Blot (WB) technique. Individual vastus lateralis muscle fibers (n = 264) were isolated and clipped into two portions, one for fiber-typing and one for protein identification. Following fiber type determination, WB destined fiber segments were combined into fiber type specific pools (20 fibers/pool) and assessed for GAPDH, actin, Citrate Synthase, and total p38 content. GAPDH expression was 69%, 92%, 159%, and 200% more abundant in MHC I/IIa, MHC IIa, MHC IIa/IIx, and MHC IIx pools when compared to MHC I, respectively. Inversely, Citrate synthase content was 526%, 497%, 316%, and 47% more abundant in MHC I, MHC I/IIa, MHC IIa, and MHC IIa/IIx when compared to MHC IIx, respectively. Similar to GAPDH, total p38 expression was 67% greater in MHC IIa versus MHC I fibers. These data establish a novel application of WB combined with SDS-PAGE for fiber type specific protein analysis in human skeletal muscle. These initial results show content of particular proteins exist in a hierarchal fashion throughout the continuum of human skeletal muscle fiber types. Application of these methods will enhance our understanding of skeletal muscle health profiles among physically active and clinically based populations. / Access to thesis permanently restricted to Ball State community only / School of Physical Education, Sport, and Exercise Science

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