What type of filing technique should be avoided to prevent nail splitting?

The filing technique that should be avoided to prevent nail splitting is the back-and-forth motion. This technique creates friction and stress on the nail, which can lead to weakening the nail structure and causing it to split or break. When the file is moved in both directions, it can create uneven pressure that damages the nail edges.

In contrast, using gentle straight strokes or filing in one direction is beneficial for maintaining nail integrity. These methods minimize the risk of causing splits or breaks in the nail while allowing for more controlled shaping. Sanding upward can also be harmful, but it primarily serves to create volume rather than promoting nail health. Therefore, avoiding the back-and-forth technique is crucial for nail care during manicures.