屈伸

1. Origins, structure, and basic meaning

• Structure: 屈伸 (くっしん) combines bending 屈 and extending 伸 as a paired movement.
• Basic usage: It describes flexing and straightening a joint such as a knee or ankle during warm-up or movement checks.

2. Common pitfalls and similar expressions

• Both flexion and extension
  • 屈伸 names the complete bend-and-straighten movement, not motion in only one direction.