Cook Korrine, Atcherson Samuel R
Department of Audiology and Speech Pathology, University of Arkansas for Medical Sciences, University of Arkansas at Little Rock, 2801 South University Avenue, Little Rock, AR 72204, USA.
ScientificWorldJournal. 2014 Mar 20;2014:702723. doi: 10.1155/2014/702723. eCollection 2014.
The purpose of this study is to identify whether or not different materials of softball bats (wooden, aluminum, and composite) are a potential risk harm to hearing when batting players strike a 12'' core .40 softball during slow, underhand pitch typical of recreational games. Peak sound pressure level measurements and spectral analyses were conducted for three controlled softball pitches to a batting participant using each of the different bat materials in an unused outdoor playing field with regulation distances between the pitcher's mound and batter's box. The results revealed that highest recorded peak sound pressure level was recorded from the aluminum (124.6 dBC) bat followed by the composite (121.2 dBC) and wooden (120.0 dBC) bats. Spectral analysis revealed composite and wooden bats with similar broadly distributed amplitude-frequency response. The aluminum bat also produced a broadly distributed amplitude-frequency response, but there were also two very distinct peaks at around 1700 Hz and 2260 Hz above the noise floor that produced its ringing (or ping) sound after being struck. Impulse (transient) sounds less than 140 dBC may permit multiple exposures, and softball bats used in a recreational slow pitch may pose little to no risk to hearing.
本研究的目的是确定在休闲比赛中常见的慢速低手投球时，击球手使用不同材质（木质、铝质和复合材料）的垒球棒击打12英寸、.40核心的垒球时，是否会对听力造成潜在危害。在一个未使用过的室外运动场，按照投手丘与击球区之间的规定距离，对一名击球参与者进行了三次受控的垒球投球测试，分别使用每种不同材质的球棒，同时进行了峰值声压级测量和频谱分析。结果显示，记录到的最高峰值声压级来自铝质球棒（124.6 dBC），其次是复合材料球棒（121.2 dBC）和木质球棒（120.0 dBC）。频谱分析显示，复合材料球棒和木质球棒具有相似的广泛分布的幅频响应。铝质球棒也产生了广泛分布的幅频响应，但在本底噪声之上约1700 Hz和2260 Hz处还有两个非常明显的峰值，这使得球棒在被击打后会发出清脆的（或砰砰的）声音。低于140 dBC的脉冲（瞬态）声音可能允许多次暴露，而在休闲慢速投球中使用的垒球棒可能对听力几乎没有风险。
