Catgut suture treatment produces roughly twice the stitch-holding time of plain catgut, but greater tissue inflammation occurs. Full tensile strength is extended to 18–21 days. It is brown rather than straw-colored, and has improved smoothness due to the dry presentation of the thread (plain catgut is wet). It is otherwise similar to plain catgut. Fast catgut suture is heat-treated to give even more rapid absorption in the body. The first known absorbable sutures were made of the intestines of sheep. The manufacturing process was similar to that of natural musical strings for violins and guitar, and also of natural strings for tennis
Strings (tennis) or more of stringbed stiffness. However, many players who hit the ball hard enough to break the strings simply restring rackets whenever the strings break. The United States Racquet Stringers Association (USRSA) offers two levels of certification for stringers: the Certified Stringer and the Master Racquet Technician, of which around 350 exist worldwide. The Master Racquet Technician certification process includes testing of the stringer's ability to string a racquet, perform grip work, identify mistakes in an improperly strung racquet, and pass a written test that covers not only strings, but racquet technology as well. Since 2004, "RSi," the USRSA's monthly