The knucklebones of sheep, goats, and other animals were sometimes used on the strands of Roman scourges. A weight was also added to the end to create a more forceful impact. Scourging wasn’t just about tearing the flesh but was also about impacting the muscles and internal organs with a concussive force. This 3-strand design has weights at each end and features five pieces of real sheep/goat knucklebone. (NOTE: It is a myth that all Roman flagrums had nine ends. There is historical evidence for three-strand scourges, after which this replica has been patterned.)
Of course, there are many details we don’t about the scourges the Romans used specifically on Jesus and many scholars believe that the soldiers often used more than one type of whip as well as reeds when they beat a victim. Findings seem to show that they sometimes used different tools on different parts of the body. This also explains why some teach that the Romans beat directly on the back but others say that they would sometimes whip from the back over the individual’s shoulder or around the side to hit the front (and vise versa). A swing like this (from the back to front or from the front to the back) would increase the impact of the blow.