Joints Cracking

Q:  What is actually happening when I hear my bones crack during a strength training workout?

A: The cracking you are hearing during the workout is originating from your joints and not your bones.

Joints crack for three main reasons:

• Synovial Fluid:  Joints crack due to gases escaping from the synovial fluid.  Synovial fluid exists in all joints and acts as a joint lubricant. The fluid contains the gases oxygen, nitrogen, and carbon dioxide.  When a joint is moved through its range of motion, a gas bubble can escape or “burst” causing a cracking sound.  The escaped gas will dissolve back into the synovial fluid in about 30 minutes.
• Tendons and Ligaments:  Cracking may occur as the ligaments and tendons that pass over the joint slide past bumps or imperfections on the bones.
• Arthritis:  Arthritis typically results in a loss of cartilage in the joint.  The lack of smooth cartilage causes a rough joint surface.  As the joint moves, the rough surface will result in grinding or cracking.