What action is disallowed with regards to the grip when performing a bench press?

Using a reverse grip or spider grip is disallowed in the bench press due to safety and standardization reasons. Powerlifting seeks to maintain uniformity in how lifts are performed and judged. The reverse grip, which involves the palms facing towards the lifter, can create instability and increase the risk of injury, especially when lifting heavy weights. Additionally, the spider grip, where the lifter's thumb does not wrap around the bar, further compromises grip security. Both grips can lead to improper lifting technique and potential accidents, making them non-compliant with the established rules of competition. This ensures that all lifters use a standard overhand grip, which is widely recognized and promotes fairness in competition.

The other options address various requirements for grip that align with the official regulations, such as the need for fingers to be appropriately placed or the stipulation regarding hand usage, which upholds safety and standard practices.