ISSNIP

Event Name Seminar by Prof. Toshio Moritani: Electrophysiology for Health and Disease
Start Date 3rd Apr 2008 7:00pm
End Date 3rd Apr 2008 8:00pm
Duration 1 hour
Description

Location: Engineers Australia, Engineering House, Ground Level, 21 Bedford Street, North Melbourne 

ARC ISSNIP and RMIT Foundation with IEEE Vic Chapter invite you to a talk by Prof Toshio Moritani who will give a guest lecture on his research as detailed below Abstract: Delayed onset of muscle soreness (DOMS). We investigated the physiological effects of static muscle stretching upon delayed onset of muscle soreness (DOMS) in conjunction with the spinal alpha motoneuron pool excitability and peripheral muscle blood flow. The result of reduction in alpha motoneuron excitability was entirely consistent with earlier studies, suggesting that the inverse myotatic reflex (Ib inhibition) may be the basis for the relief of muscle soreness by static stretching. Fusiomotor sensitivity after prolonged stretch shortening cycle exercise. We have recently performed comparative analyses of T-reflex, elicited by Achilles tendon tap and H-reflex, elicited by electrical stimulation of tibial nerve before and immediately after, 2-h and 24-h after 2-hour running (n =10). The difference between H- and T-reflex amplitudes 2-hour after the running might suggest that the sensitivity of fusiomotor activity was reduced by 2-hour running. Furthermore the reduced impact force might signify deteriorated stiffness regulation of muscle-tendon complex. Mechanomyogram changes during muscle fatigue. Previous studies have indicated that mechanomyogram (MMG) amplitude and frequency components might represent the underlying motor unit (MU) recruitment and firing rate (rate coding). Interestingly, MMG amplitude actually decreases at higher force levels at which MUs might be firing at tetanic rates, causing a fusion-like contraction leading to a diminished MMG amplitude, while its frequency increases (Moritani and Yoshitake, 1998; Yoshitake and Moritani, 1999). These data suggest that MMG analyses might offer not only MU recruitment and rate coding characteristics, but also their mechanical properties, the fusion properties of activated MUs that could not be obtained by conventional EMG analyses. Etiology of Obesity (Diabetes Mellitus) and the Autonomic Nervous System. The causes of most cases of human obesity are still unknown. Recent identification of obese genes (leptin, uncoupling protein (UCP) families and Trp^64 Arg polymorphism of the *?_3 *-adrenergic receptor) has increased our understanding of the patho-physiology of obesity. Our data strongly suggest that obese individuals may possess normal sympatho-vagal activities at resting conditions, but may show much lower autonomic responsiveness against thermogenic perturbations such as acute cold exposure and diet-induced thermogenesis. Our recent studies (Amano et al., 2001, Nagai et al., 2004; Ueno and Moritani, 2003) has demonstrated a strong possibility that ANS activity can be enhanced by exercise training among previously obese individuals with reduced ANS activity. Functional Electrical Stimulation for Health and Disease. Exercise increases glucose uptake by the translocation of GLUT-4 glucose transporters, similar to the action of insulin, but through independent mechanisms. There are however only few studies available that have investigated the effects of electrical stimulation (ES) upon muscle energy metabolism and in particular muscle glucose uptake. Our results indicated that oxygen uptake was significantly increased by approximately 2-fold in response to muscle stimulations. Similarly, muscle glucose uptake determined by glucose infusion rate (GIR) in hyperinsulinemic-euglycemic clamp was acutely increased in response to electrically-induced contractions (p < 0.01) (Hamada et al., 2003). Furthermore, GIR remained elevated during the post-stimulation period for at least 90 min (p < 0.01). The subsequent study examining the acute metabolic effects of ES to lower extremities in comparison with voluntary cycle exercise (VE) at identical intensity demonstrated that this post ES effect on whole-body glucose uptake was significantly greater than that of the post VE period (p < 0.01) (Hamada et al., 2004). It was concluded that ES may become a useful modality that could enhance glucose uptake in skeletal muscle through insulin-independent mechanisms of those patients with peripheral insulin resistance, such as non-insulin-dependent diabetes mellitus and/or chronic patients with progressive muscle atrophy. Toshio Moritani was born in Japan in 1950. He received his Ph.D. degree in Sports Medicine from the University of Southern California in 1980. Following faculty appointments at the University of Texas at Arlington and Texas A&M University, he returned to Japan. In 2000, he was appointed Professor of Applied Physiology at the Graduate School of Human and Environmental Studies at Kyoto University. Dr. Moritani is the Editor of the Journal of Electromyography and Kinesiology. He is also serving as a member of the Editorial Board for the European Journal of Applied Physiology. He has also served as one of the Council Members and currently being the President of the International Society of Electrophysiology and Kinesiology. . 

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