Development of training methods for selective activation of the fast fiber type using skin cold stimulation

• Project/Area Number: 11680055
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 体育学
• Research Institution: Tokyo University of Pharmacy and Life Science
• Principal Investigator: YONA Masae Tokyo University, Pharmacy and Life Science, School of Pharmacy, Assistant Professor, 薬学部, 講師 (30120158)
• Co-Investigator(Kenkyū-buntansha): MURO Masuo Toho University, School of Medicine, Associate Professor, 医学部, 教授 (80112887)
• Project Period (FY): 1999 – 2000
• Project Status: Completed (Fiscal Year 2000)
• Budget Amount: ¥3,100,000 (Direct Cost: ¥3,100,000); Fiscal Year 2000: ¥1,000,000 (Direct Cost: ¥1,000,000); Fiscal Year 1999: ¥2,100,000 (Direct Cost: ¥2,100,000)
• Keywords: cooling / motor unit / threshold force / fast type / training / skin temperature / eccentric contraction / ramp contraction / 冷刺激 / 速筋線維

Research Abstract

The aim of this study was to collect data on the development of training methods for selective activation of the fast fiber type using in skin cold stimulation, using 5 experiments. In the fast experiment the effects of low temperature on the threshold force of MUs from lower to MVC force output using the cold skin stimulation method were investigated and we found that the recruited MUs from 20%MVC to approximately 6O%MVC were affected by low temperature, but the recruited MUs above 60%MVC were not affected by low temperature. We speculated that the changes of threshold force of motor units might be selectively produced by some effect of cutaneous afferent impulses in the spinal cord. In the second experiment the effects of cutaneous afferent impulses from the contralateral side were investigated and we found that the cold stimulation in the ipsilateral side was selectively facilitated by the threshold force of the HT-MUs : however, cold stimulation in the contralateral side was inhibi ted. We speculated suggested that training using cold stimulation was effective to be cooling only the part of purpose. In the third experiment the effects of low temperature on the recruitment threshold force of MUs during different rates of slow ramp contractions using the cold skin stimulation method were investigated and the results suggested that when the subjects performed the rates of the fast ramp contractions, the threshold force of MUs were affected with decreased skin temperature. However, when the subjects performed the rates of the medium and slow ramp contractions, the threshold force of MUs were not affected with decreased skin temperature, because the firing rate of MUs and the input of cutaneous afferent affected the motomeuron. In the fourth experiment the effects of low temperature on the threshold force of MUs during the eccentric ramp contraction (EC) were investigated and we found the threshold force of the HT-MUs during the EC was not significantly affected with decreased skin temperature. We supeculated that the most effective contraction using cold stimulation was the concentric contraction. In the fifth experiment subject's data who have a high rank of 100m were used to analyze the relationship between record of 100m, birthplace, training place and training wear. We found that record of 100m and the temperature of the subject's birthplace were significantly related.
We considered that the training method using skin cold stimulation was effective to selectively activate the fast fiber type.