TSUKI - basic yet powerful: Biomechanical Analysis of Vertical Punch Techniques in Karate

This research paper highlights the fundamental differences between vertical punch and horizontal punch in martial arts. It examines the biomechanical principles behind the vertical punch (tate ken) in Karate, commonly referred to as "Tsuki" in traditional Japanese martial arts. Modern scientific research in anatomy and biomechanics validates these centuries-old practices, whose importance has been long emphasized by traditional karate masters. This study analyzes the vertical punch's advantages over the horizontal punch through the examination of bone alignment, muscle engagement, and force distribution. The forearm bones (ulna and radius) align directly with the wrist and knuckles when the arm is extended in vertical alignment, creating an optimal path for transfer of approximately 80% of axial force through the strongest parts of the wrist joint while minimizing injury risk. Additionally, the analysis of muscle engagement reveals that the flexor carpi radialis muscle in vertical punches provides superior stability compared to the flexor carpi ulnaris in horizontal punches. The vertical punch also directs impact forces through the stronger index and middle metacarpals, reducing the risk of boxer's fractures which are common with horizontal punches. This research shows that the adoption of vertical punches across multiple martial arts systems and historical periods is not simply a stylistic preference but rather reflects sound biomechanical principles.