In vivo studies of peritendinous tissue in exercise

Soft tissue injury of tendons represents a major problem within sports medi cine. Although several animal and cell culture studies have addressed this, human experiments hare been limited in their ability to follow changes in specific tissue directly in response to interventions. Recently, methods ha ve allowed for in vivo determination of tissue concentrations and release r ates of substances involved in metabolism, inflammation and collagen synthe sis, together with the measurement of tissue blood flow and oxygenation in the peritendinous region around the Achilles tendon in humans during exerci se. It can be demonstrated that this region experiences an increase in bloo d flow during both static and dynamic exercise, and that exercise causes in creased metabolic activity, accumulation of inflammatory mediators (prostag landins) and increased formation of collagen type I in response to acute ex ercise. This coincides with a surprisingly marked drop in tissue pressure d uring contraction, with regards to both circulation, metabolism and collage n formation, peritendinous tissue represents a dynamic, responsive region t hat adapts markedly to acute muscular activity.