Which of the following is a common hand technique in Taekwondo?

The backfist is a common hand technique in Taekwondo that emphasizes speed and precision. It involves striking with the back of the fist, which can be particularly effective in close-range combat. This technique is generally used in quick combinations during sparring or as part of self-defense tactics. The backfist can be delivered swiftly to catch an opponent off-guard, making it a valuable skill in both sport and practical applications.

In contrast, other options like the sidekick, spinning kick, and roundhouse kick are primarily kicking techniques central to Taekwondo. While these kicks are essential components of the martial art, the focus of the question is specifically on hand techniques, which makes the backfist the correct answer in this context. Understanding the specific types of techniques—whether they are hand or foot-based—helps to categorize and refine skills appropriate for different scenarios in Taekwondo practice.