Effects of the mechanical property of equipment on the motion in sports

2005 Fiscal Year Final Research Report Summary

• Project/Area Number: 16500393
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Sports science
• Research Institution: Japan Institute of Sports Sciences, National Agency for the Advancement of Sports and Health (2005); The University of Tokyo (2004)
• Principal Investigator: HIRANO Yuichi Japan Institute of Sports Sciences, National Agency for the Advancement of Sports and Health, Department of Sports Sciences, Department Director, スポーツ科学研究部, 主任研究員 (30165196)
• Project Period (FY): 2004 – 2005
• Keywords: baseball / baseball bat / mechanical property of equipment / youth ethlete / hitting motion / practive swing / 練習効果

Research Abstract

For baseball hitting by university baseball players,
1. when the lighter or shorter bat is used, both angular velocities of lower and upper trunk of the hitter in the horizontal plane may not be decreased from the latter half of the swing to the ball impact.
2. the range of motion of the front upper arm in relation to the upper trunk may be increased when using the lighter bat, but may not be so much when using shorter one.
3. angular velocity of the longer bat may be decreased during the early stage of the swing, but may not be so much in case of the heavier one.
When the lighter bat is used by youth baseball players,
1. the angular movement phase of the bat is similar to that of the upper trunk.
2. the bat rotates more relative to the upper trunk at the ball impact.
3. each of the upper, and lower trunk, and bat rotates more at the ball impact on the global frame of reference.
Similar effects might be acquired for the daily hitting motion after 6 weeks' practice swing of lighter bat.