So what is the Interstitium and why does this "new" discovery matter? Well, as a manual therapist I cannot touch your sore muscles or adjust your stuck spine or heal inflammation in any ligaments or tendons without first going through the interstitium. This part of our body has actually been studied by physical medicine specialists in the UK and Germany for years. They call it the extracellular matrix (ECM). There are some profound connections between loading (ie. exercise, any movement) and the interstitium. When you perform any movement, the loads that enter your body are transmitted to your cells through this ECM and genes turn on as well as increases in blood supply and your body's self repair mechanism's.