What must lifters ensure when performing a deadlift?

In the context of performing a deadlift according to the standards set by the International Powerlifting Federation (IPF), maintaining a straight back throughout the lift is crucial for several reasons. Proper posture minimizes the risk of injury, particularly to the spine, and ensures that the lift is executed correctly and safely. A straight back allows the lifter to effectively engage the appropriate muscle groups, maximizing strength and stability during the lift. This adherence to technique is essential not only for performance but also for safety, as it helps prevent strains or injuries that could result from improper lifting posture.

In addition to this vital aspect of the lift, other factors mentioned in the question do not align with the requirements for a successful deadlift. For instance, lifting the bar without any weights attached does not reflect the actual competition scenario or the challenge of the lift; having weights is essential to the task. Similarly, both feet being off the ground would contradict the requirement for the lifter to maintain contact with the platform, as it is essential for balance and stability. Lastly, while time limits may exist in certain competition settings, the primary focus for the lifter is to ensure the lift is executed properly before considering any time constraints.