虛擬實境與無實球影像投影環境下的棒球揮棒運動學比較：打者對不同投球位置的適應性分析

A kinematic comparison of baseball swing in virtual reality and non-ball video projection environments: Batters’adaptations to different pitch locations

緒論：虛擬訓練環境已日益應用於運動訓練，以提升技能學習與運動表現。此類訓練方法的有效性取決於其能否忠實再現真實世界的空間知覺與運動機制。在棒球打擊中，打者能否根據不同的投球位置調整揮棒姿勢，對於比賽表現至關重要。然而，目前針對虛擬實境（Virtual Reality，VR）與無實球影像投影（Video Projection，VP）訓練環境如何影響這些姿勢調整的研究仍然有限。因此，本研究旨在探討VR與VP環境如何影響打者針對好球帶內不同投球位置的揮棒姿勢調整。方法：九名右打之大學棒球選手參與本研究。每位參與者在VR與VP的條件下觀看投球影片並進行空揮動作（無實際擊球）。投球影片中，投手以時速100公里投出直球至三個不同的好球帶區域：內角、中間、外角。本研究分析球棒速度峰值瞬間時的揮棒姿勢，關鍵生物力學變數包括：肘部屈曲角度、手臂外展角度、上軀幹旋轉與伸展角度、骨盆旋轉角度、髖部內旋角度及膝部屈曲角度。使用二因子重複量數變異數分析，比較不同投球位置與揮棒條件下的關節角度變異。結果：研究結果顯示，在後手肘屈曲、上軀幹旋轉及骨盆旋轉方面存在顯著的交互作用（p < .05）。在VR條件下，打者面對內角與中間球時，後手肘屈曲角度、上軀幹旋轉角度及骨盆旋轉角度顯著大於外角球（p < .05），但中間球的骨盆旋轉角度未達統計顯著（p = .067）。相較之下，在VP條件下，不同投球位置間的這些關節角度並無顯著差異。此外，條件間比較顯示，在VR條件下，打者面對內角球時的骨盆旋轉角度顯著大於VP條件（p = .017）。結論：本研究結果表明，VR相較於VP，更能誘發打者針對不同投球位置的揮棒姿勢調整。VR的高度沉浸性增強了空間知覺，使打者能夠更有效地辨識投球位置，並適時調整揮棒動作。相較之下，VP可能因深度知覺不足，而無法引發適當的生物力學反應。因此，基於本研究發現，建議採用VR來訓練打者適應不同投球位置的揮棒機制。

Introduction: Virtual training environments have been increasingly utilized in sports training to enhance skill acquisition and improve performance. The effectiveness of these training methods depends on their ability to replicate real-world spatial perceptions and movement mechanics. In baseball batting, the ability to adjust swing posture based on different pitch locations is crucial for performance. However, little research has examined the effect of virtual reality (VR) and non-ball video projection (VP) environments influence these adjustments. This study examined how VR and VP batting environments affect swing posture adjustments in response to different pitch locations within the strike zone. Method: Nine collegiate baseball players, all right-handed batters, participated in this study. Each participant performed dry swings while watching a pitching video displayed under VR and VP conditions without a real ball being projected. The video featured a pitcher throwing a straight ball at 100 km/h towards three locations in the strike zone: medial (inside), center, and lateral (outside). Swing posture at peak bat velocity was analyzed, with key biomechanical variables including elbow flexion, arm abduction, upper trunk rotation and flexion, pelvic rotation, hip internal rotation, and knee flexion. Two-way repeated measures ANOVA was employed to evaluate differences in joint angles among pitch locations and between swing conditions. Results: A significant interaction effect was observed in back elbow flexion, upper trunk rotation, and pelvic rotation (p < .05). Under VR conditions, players demonstrated greater back elbow flexion, upper trunk rotation, and pelvic rotation when swinging at medial and center balls compared to lateral balls (p < .05), except for pelvic rotation in center balls (p = .067). Conversely, under VP conditions, there were no significant differences in these joint angles across different pitch locations. A between-condition analysis also revealed that pelvic rotation was significantly greater for medial balls in VR than in VP (p = .017). Conclusion: These findings suggest that VR condition elicits more pronounced swing posture adaptations in response to varying pitch locations compared to VP condition. The immersive nature of VR enhances spatial awareness, enabling batters to distinguish pitch locations more effectively and adjust their swings. VP may lack the depth perception necessary to elicit appropriate biomechanical responses. Given these findings, VR is recommended for training batters to adjust swing mechanics to different pitch locations.