Behind-the-back barbell wrist curl:
Standing tall, place a barbell behind your back, your hands shoulder-width apart and your palms facing behind you. Your arms should be fully extended so the bar rests just below your glutes. Flexing your wrists, curl the barbell toward your body. Pause, then lower the bar to the starting position. Only the wrists should move during the exercise.
Mistakes and Recommendations:
Keep a straight angle in the elbow joint.
Control your movements. You can perform the exercise in any variant (sitting, kneeling, etc.).
Do not move too fast. It significantly reduces the movement efficiency.
Breath. Exhale while the bar goes up, and exhale when it goes down.
Keep the right back position. Work only with the target muscles!
Do not forget to warm up. It reduces the risk of traumas and makes the exercise more efficient.
Keep your body stable and do not make long pauses.

Behind-the-back barbell wrist curl.