Big data technology has transformed sports training and coaching by enabling data-driven decision-making and performance optimization. This study examines its impact on training decisions and coaching leadership using university basketball as a case study. The findings show that big data enhances training efficiency through individualized plans, real-time monitoring, and tactical adjustments, leading to measurable improvements in player and team performance. Big data also strengthens coaching leadership by providing objective insights, improving communication through visual tools, and enabling self-assessment of strategies. Tactical optimizations, such as improved defensive coverage and balanced shooting distribution, highlight the value of data-driven approaches in addressing weaknesses and enhancing game strategies. While challenges like data standardization and privacy concerns remain, big data's integration into sports continues to unlock new opportunities for optimizing performance and advancing team success.