本研究將探討在環境控制下對?同品牌聚氨酯(polyurethane, PU)?球進?性能比較之分析。其研究方法以實驗方式對一種品牌之PU?球球芯進??同環境條件控制，並進?圓周尺寸、重?、恢?係?(coefficient of restitution, COR)與壓縮值等??值之測試，?解PU?球球芯特性之趨勢後；再以?種品牌PU?球球體為?，進??同環境條件及球速控制下，測試其恢?係?特性。經由實驗結果顯示，?同環境氣候確實會造成PU?球球芯圓周尺寸、重?、壓縮值及恢?係?之變化。此外，在?同溫?、溼?控制條件以ASTM標準檢測球速97km/h等速測試下，?種品牌的COR值差?造成反彈球速差在0.88~1.94km/h間，顯示?球選手面對?同的比賽單位時，需要?佳的反應?適應?同品牌所造成之影響。最後，在?同球速測試下，?種品牌的COR值隨著球速愈快而呈現愈低之趨勢，但?同品牌之影響程?並?相同。所以如何於?同氣候比賽下，選擇合適之比賽用PU?球將是一個重要課題。

This study analyzed the core of a PU softball to better understand the characteristics of circumference, weight, coefficient of resuming (COR) and compressing values. Next, on two brands of PU softballs were experimented to understand the characteristics of COR of the softballs under different environmental conditions and speed testing conditions. The experiment results showed that different environmental conditions changed the parameters of the circumference, weight, COR and compression of the PU softball core. When the same ball speed (97km/h) was set under different temperatures and humidity conditions, the difference in rebound speeds of the two brands was more than 0.88 Km/h. The maximum difference was up to 1.94Km/h. Also, by testing the ball with different speeds, we found that the higher the ball speed, the lower COR. As a result, the differences of characteristics found in each brand of PU softball during different environmental conditions lead to the question of fair play, so the subject arises as to choosing a suitable PU softball in relation to different climates.