Infragravity waves in the surf and swash zone play a big role in shaping coastal areas. This study looked at how these waves are generated and how they move in the water. They found that there are two main ways these waves are created: by long waves released from groups of waves, and by oscillations at the surf zone. By analyzing data from labs and beaches, they discovered clear patterns in how these waves interact with the shoreline. The width of the surf zone and the type of wave breaking determine which mechanism is more dominant. This research helps us understand how waves affect coastal environments and how they can be studied in the field.