Which part of the lifter's body should the t-shirt's sleeve monitor?

The correct answer is that the t-shirt's sleeve should monitor the deltoid area of the lifter's body. In powerlifting, particularly during the bench press, the deltoid muscles play a crucial role in stabilizing the shoulder joint and controlling the movement of the arms. A t-shirt designed for this purpose typically features sleeves that are adapted to ensure that they do not affect the range of motion or the execution of the lift while still providing adequate support and observation.

Monitoring the deltoid area is significant for referees to ensure that the lifter's technique adheres to the rules and standards set by the International Powerlifting Federation (IPF). This area is where any potential illegal lifting techniques or adjustments can often be observed, such as improper shoulder positioning or excessive reliance on the shirt's material for support, which would invalidate the lift. Therefore, the focus on the deltoid area indicates a key part of the upper body involved in executing the bench press.