From the first softball game in 1887 to the late 1960s, batters came to the plate with a wooden bat. In 1969, sporting goods manufacturer Easton introduced the first aluminum bat made for everyday play. This revolutionized the sport and opened the doors for new materials. Advancements in softball bat construction have led to higher performance equipment and stricter technical regulations to level the playing field and protect athletes on the field.
Materials
The Amateur Softball Association of America governs the sport in the United States and certifies equipment for use in its sanctioned games. The ASA puts its seal of approval on four types of bats: wooden, single-wall aluminum, multi-wall aluminum and carbon composite. Wooden bats are permitted for use by the ASA, but not by the National Collegiate Athletic Association. Aluminum and composite are the only bats approved for use in college softball.
Aluminum bats gained popularity, according to Kettering State University physicist Daniel Russell, for three reasons: Their lighter frames translate to faster swings; their hollow construction leads to greater energy transfer known as the "trampoline effect"; and aluminum bats have a larger sweet spot, or space where the greatest transfer of energy from bat to ball is made.
Composite bats, specifically those made of carbon or graphite, perform even better than aluminum. Russell writes that this is due to the composite materials' ability to better control the trampoline effect. The swing weight, too, can be better controlled.
2000 Performance Standards
ASA-approved bats must meet the performance standards jointly developed with the American Society of Testing and Materials. The primary focus of the standard is batted ball speed, or how fast the ball projects when contact is made. The fastest batted ball speed allowed under ASA's Bat and Ball Certification Program, also known as the ASA 2000 bat standard, is 125 feet per second or 85 mph.
2004 Performance Standards
A 2004 revision of the ASA bat program accommodated the growing use of carbon composite bats, which are capable of being swung faster and create higher batted ball speeds. The ASA 2004 program caps the batted ball speed at 98 mph and uses a new testing model for certification. According to the ASA, "Even though this limit is numerically higher than the ASA 2000 bat performance standard, in science and in practice the 2004 bat standard is actually a reduction compared to the 2000 bat standard." In order to be used in tournament play, ASA 2000 bat makers must recertify their older models under the new program.
Barrel Stiffness
Russell, the Kettering University physics professor, writes that bat barrels in softball differ from those used in baseball. Baseballs have a higher coefficient of restitution than softballs, which means the ball springs off the bat more quickly. Softball bats are therefore less stiff as they make contact with slower pitched balls with a lesser COR.
References
- Funding Universe: Easton Sports
- Amateur Softball Association of America: 2004 Certified Bats
- National Collegiate Athletic Association; "NCAA Softball 2010 and 2011 Rules and Interpretations;" Teresa Smith, editor; 2009.
- Amateur Softball Association; "2005 Official Rules of Softball, Umpire Edition"; 2005.
- Kettering University; "Are Composite Bats better than Aluminum Bats?"; Daniel Russell; 2005.
- Kettering University; "Why Aluminum Bats Can Perform Better than Wood Bats"; Daniel Russell; 2005.
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