Planks can be performed using which of the following positions?

Planks are a core-strengthening exercise that primarily engage the abdominal muscles, lower back, and shoulders. The fundamental aspect of the plank is maintaining a stable position while holding the body in a straight line, which is best achieved in a horizontal posture.

Performing a plank on your hands or forearms is the standard technique. In this position, you support your body weight either on your palms, as in a high plank, or on your elbows, as in a low plank. Both variations emphasize core stability and strength. Maintaining this position requires significant engagement from the core and also activates other supportive muscle groups, such as the shoulders and glutes.

The other positions mentioned do not effectively engage the core in the same way. For instance, performing a plank on your back does not create the tension needed to work the core effectively, as the body is not in a position to resist gravity properly for this specific type of exercise. Likewise, while knee or standing positions may engage the core to some degree, they do not provide the same level of difficulty or focus on the muscles targeted in a traditional plank. Thus, only the position on hands or forearms meets the criteria for an effective plank exercise.